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Showing 25 results for alijani
Tofigh Saadi, Bohloul Alijani, Ali Reza Massah Bavani, Mehry Akbary,
Volume 3, Issue 3 (10-2016)
Volume 3, Issue 3 (10-2016)
Abstract
Understanding the changes in extreme precipitation over a region is very important for adaptation strategies to climate change. One of the most important topics in this field is detection and attribution of climate change. Over the past two decades, there has been an increasing interest for scientists, engineers and policy makers to study about the effects of external forcing to the climatic variables and associated natural resources and human systems and whether such effects have surpassed the influence of the climate’s natural internal variability. The definitions used in the 5th assessment report were taken from the IPCC guidance paper on detection and attribution, and were stated as follows: “Detection of change is defined as the process of demonstrating that climate or a system affected by climate has changed in some defined statistical sense without providing a reason for that change. An identified change is detected in observations if its likelihood of occurrence by chance due to internal variability alone is determined to be small. Attribution is defined as the process of evaluating the relative contributions of multiple causal factors to a change or event with an assignment of statistical confidence”. Detection and attribution of human-induced climate change provide a formal tool to decipher the complex causes of climate change. In this study the optimal fingerprinting detection and attribution have been attempted to investigate the changes in the annual maximum of daily precipitation and the annual maximum of 5-day consecutive precipitation amount over the southwest of Iran.
This is achieved through the use of the Asian Precipitation—Highly Resolved Observational Data Integration Towards Evaluation of Water Resources Project(APHRODITE) dataset as observation, a climate model runs and the standard optimal fingerprint method. To evaluate the response of climate to external forcing and to estimate the internal variability of the climate system from pre-industrial runs, the Norwegian Climate Center’s Earth System Model- NorESM1-M was used. We used up scaling to remap both grid data of observations and simulations to a large pixel. This remapped pixel coverages the area of the southwest of Iran. The optimal finger printing method needs standardized values like probability index(PI) or anomalies as input data, since the magnitude of precipitation varied highly from one region to another. The General Extreme Value distribution (GEV) is used to convert time series of the Rx1day and Rx5day into corresponding time series of PI. Then we calculated non-overlapping 5-year mean PI time series over the area study. In this research, we applied optimal fingerprinting method by using empirical orthogonal functions. The implementation of optimal fingerprinting often involves projecting onto k leading EOFs in order to decrease the dimension of the data and improve the estimate of internal climate variability. A residual consistency test used to check if the estimated residuals in regression algorithm are consistent with the assumed internal climate variability. Indeed, as the covariance matrix of internal variability is assumed to be known in these statistical models, it is important to check whether the inferred residuals are consistent with it; such that they are a typical realization of such variability. If this test is passed, the overall statistical model can be considered suitable.
Results obtained for response to anthropogenic and natural forcing combined forcing (ALL) for Rx1day and Rx5day show that scaling factors are significantly greater than zero and consistent with unit. These results indicate that the simulated ALL response is consistent with Rx1day observed changes. Also, it is found that the changes in observed extreme precipitation during 1951-2005 lie outside the range that is expected from natural internal variability of climate alone and greenhouse gasses alone, based on NorESM1-M climate model. Such changes are consistent with those expected from anthropogenic forcing alone. The detection results are sensitive to EOFs. We estimate the anthropogenic and natural forcing combined attributable change in PI over 1951–2005 to be 1.64% [0.18%, 3.1%, >90% confidence interval] for RX1day and 2.5% [1%,4%] for RX5day.
Morteza Esmailnejad, Bohlol Alijani,
Volume 4, Issue 1 (4-2017)
Volume 4, Issue 1 (4-2017)
Abstract
Climate change is one of the crucial factors, which threaten many sector such as agriculture, water resource for decades, and the sector is more sensitive to climatic conditions. Communities are the most vulnerable to the adverse impacts of climate change and variability because of their low adaptive capacity. One of the challenges of climate change and human spatial dimensions of climate change in international borders where climate change, and creates special challenges. Populated places in the East where rapid urbanization, industrialization and agricultural intensification result in vulnerability to climate change, water shortages as the main concern arises.
Adaptation to climate change is the adjustment of a natural or human system to moderate the impacts of climate change, to take advantage of new opportunities or to cope with the consequences. Trying to identify the attitudes of people and their mental models of climate change can provide application to manage the post-change. Culture and engineering modeling approaches minds of scientists for climate risk management and climate change consequences have adopted. The review focused on farmers’ perceptions on changes in temperature, precipitation (rainfall), adaptation measures taken by farmers, barriers inhibiting these adaptation measures and the socioeconomic determinants of adaptations to climate change in Sistan plain.
The aim of this study is to provide mental system model, and understanding of climate change is to adapt these areas. To carry out this study to develop a theoretical framework for the model to adapt to climate change was discussed in Helmand. The field study was to assess the views of people on climate change action. The review found out that most farmers in this region are aware that the continent is getting warmer, and precipitation or rainfall patterns have changed. People with new changes and features adaptive approach to the challenges ahead were investigated. This data is based on knowledge (awareness) of water and climate change adaptation and mitigation strategies and be ready. So how compliance action is preventive in nature and to reduce the repercussions of climate change and the potential benefits of a region in the face of these side effects are formed. Most respondents aged over twenty years are at least a decade to climate change are felt to be most frequent subjects 30 to 40 years old. The data collected were processed using statistical techniques and modeling for ranking and evaluation of adaptation strategies were created and ASI index. The results for the insights, policy makers and service providers for local development is important, and can be targeted measures used and the promotion and adoption of coping mechanisms with the potential to build resilience and adapt to climate change and the resulting effects environmental prepare.
The results showed that most people in the region following the election of climate change is adaptive behavior. In total, there are 15 strategies in the region. The ASI index rating of strategies to change the pattern of cultivation, selection of resistant strains, reducing the amount of land-cultivated variety is the pattern of adaptation to environmental changes. Ensuring awareness of and adaptation to climate variability call was conducted with the cooperation of the people. Therefore, variability of climate and natural features of the area was measured by various options. The results show that already sampled respondents in the community are aware of climate change. 60% of respondents strongly observed signs of climate change and the dry season and low rainfall and warmer temperatures to believe. The main adjustment options adopted by farmers to temperature in the region include change of product types and number of ships that 61.6 percent of the farmers that their efforts. Another priority is that 39 percent of them tend to change sowing dates and planting varieties resistant to drought. The main recommendations for adapting to new circumstances in this region to stimulate the economy and livelihood of local people can be to diversify crop production (food for example, and cash crops, annual and permanent crops greenhouse) and the use of foreign income from farm sources (ecotourism, rural tourism) can be cited.
Bohlole Alijani, Meysam Toulabi Nejad, Fariba Sayadi,
Volume 4, Issue 3 (9-2017)
Volume 4, Issue 3 (9-2017)
Abstract
Urban climate is strongly influenced by the processes of urban work and life. Expansion of cities and consequently increased human constructions causes to changes in urban climate. The rising temperature of cities rather than the surroundings is one of the effects linked to direct human intervention.
Building heating, air pollution and the use of inappropriate materials in the flooring streets (like asphalt streets due to dark colors in energy-absorption) are effective in phenomenon of urban heat islands that makes unfavorable environment for citizens. Paying attention to the urban surfaces like sidewalk, streets and rooftops has a great role in decreasing effect of this phenomenon. Due to growing urbanization and subsequently cities development, urban heat islands have taken a growing trend in big cities.
In general, the urban heat-island is a result of urbanity features, air pollution, human warmth, presence of impervious surfaces in the city, thermal properties of materials and geometry of urban areas. Heat island phenomenon is a result of many factors that are summarized below: (1) urban Geometry (morphometry) (2) thermal properties of materials which increase the sensible heat storage in the urban texture (3) released human heat as a result of fuel combustion and animal metabolism (4) urban greenhouse gases, leading to an increase in long wave radiation, atmospheric contamination and therefore warmer atmosphere (5) reduction of evaporation levels in cities, which means that energy will be released more as tangible rather than latent heat (6) reduction of turbulence and heat transfer through the streets.
This study aimed to simulate and calculate the maximum amount of heat island (UHI max) according to the conditions of urban geometry in the region of Kucheh bagh in Tabriz that is a pioneer study in Iran.
The study area is located in Kuche bagh region at the intersection of the streets of Ghods and Farvardin in the city of Tabriz.
The Oke’s numerical-theoretical equation was used for this study. First, the geometry of the target area using the radius of 15 meters from the axis of the road was divided into separate blocks. The ratio of street width (W) and height of buildings (H) was calculated in GIS software and at the end, the intensity of UHImax was calculated and simulated using Oke equation.
The urban geometry including building height and street width is calculated using Equation 1.
The theoretical- numerical basis of this equation shows that simulation of H/W ratio is an appropriate ways to describe urban geometry. Increasing the value of this ratio could lead to an increase in urban heat-island through modeling. This model has many advantages compared to other methods used to estimate the urban heat island. So, the selected parameter to calculate urban geometry and the model used to estimate the maximum intensity of heat island is the ratio of H / W and OKE model, respectively. In addition, the average height of buildings located within a radius of 15 meters and an average width of passages were calculated from the equation 2 and 3, respectively.
After calculating the geometry of the study area, the results showed that the blocks E, G and D in terms of height of the buildings have a heterogeneous distribution, but the distribution of blocks C, I and J is illustrative of their standard configuration. Although the blocks E, F and J in terms of street width are less diverse compared to other blocks, but in terms of height of buildings (8.6, 7 and 5 meters) have a different pattern that maximum values of their UHI are 8.3, 7.5 and 6.3 degrees, respectively. Three blocks B, H and I, in addition to their similarity according to street width and height of the buildings, in terms of the ratio of H / W and heat island intensity with the values of 9.6, 9.8 and 10.2 degrees are homogeneous.
It was also found that the greatest difference between the H / W ratio is related to block A (0.54) and block H (1.98); this difference has caused that greatest difference between the maximum intensity of UHI would calculated between the two blocks equal to 5.2 degree.
Misconfiguration causes that energy leaving from city surface deal with the problem due to narrow passages and high buildings. Therefore, consideration appropriate width of passages and streets and height of buildings are necessary to ease heat leaving and reduce intensity of UHI.
These simulations showed that high buildings and narrow streets intensify the heat islands. While in the presence of short buildings and wide streets, the UHI max is lowered. When the ratio H / W in the studied urban area is between 0.54 to 0.81, UHI max remains between 5 to 6.6 C˚, when this ratio increases to 1.01 to 1.98, UHI max will be between 7.5 and 10.2 C˚. The result also revealed that block A and H with 5 and 10.2 C˚ have the minimum and maximum value of UHI intensity, respectively. So can be concluded that block A and H have the most standard and non-standard urban configuration in the region. The estimates from regression model showed that the street width (91.6%) is more effective than the height of the buildings (6.6%) in changing UHI max.
Building heating, air pollution and the use of inappropriate materials in the flooring streets (like asphalt streets due to dark colors in energy-absorption) are effective in phenomenon of urban heat islands that makes unfavorable environment for citizens. Paying attention to the urban surfaces like sidewalk, streets and rooftops has a great role in decreasing effect of this phenomenon. Due to growing urbanization and subsequently cities development, urban heat islands have taken a growing trend in big cities.
In general, the urban heat-island is a result of urbanity features, air pollution, human warmth, presence of impervious surfaces in the city, thermal properties of materials and geometry of urban areas. Heat island phenomenon is a result of many factors that are summarized below: (1) urban Geometry (morphometry) (2) thermal properties of materials which increase the sensible heat storage in the urban texture (3) released human heat as a result of fuel combustion and animal metabolism (4) urban greenhouse gases, leading to an increase in long wave radiation, atmospheric contamination and therefore warmer atmosphere (5) reduction of evaporation levels in cities, which means that energy will be released more as tangible rather than latent heat (6) reduction of turbulence and heat transfer through the streets.
This study aimed to simulate and calculate the maximum amount of heat island (UHI max) according to the conditions of urban geometry in the region of Kucheh bagh in Tabriz that is a pioneer study in Iran.
The study area is located in Kuche bagh region at the intersection of the streets of Ghods and Farvardin in the city of Tabriz.
The Oke’s numerical-theoretical equation was used for this study. First, the geometry of the target area using the radius of 15 meters from the axis of the road was divided into separate blocks. The ratio of street width (W) and height of buildings (H) was calculated in GIS software and at the end, the intensity of UHImax was calculated and simulated using Oke equation.
The urban geometry including building height and street width is calculated using Equation 1.
The theoretical- numerical basis of this equation shows that simulation of H/W ratio is an appropriate ways to describe urban geometry. Increasing the value of this ratio could lead to an increase in urban heat-island through modeling. This model has many advantages compared to other methods used to estimate the urban heat island. So, the selected parameter to calculate urban geometry and the model used to estimate the maximum intensity of heat island is the ratio of H / W and OKE model, respectively. In addition, the average height of buildings located within a radius of 15 meters and an average width of passages were calculated from the equation 2 and 3, respectively.
After calculating the geometry of the study area, the results showed that the blocks E, G and D in terms of height of the buildings have a heterogeneous distribution, but the distribution of blocks C, I and J is illustrative of their standard configuration. Although the blocks E, F and J in terms of street width are less diverse compared to other blocks, but in terms of height of buildings (8.6, 7 and 5 meters) have a different pattern that maximum values of their UHI are 8.3, 7.5 and 6.3 degrees, respectively. Three blocks B, H and I, in addition to their similarity according to street width and height of the buildings, in terms of the ratio of H / W and heat island intensity with the values of 9.6, 9.8 and 10.2 degrees are homogeneous.
It was also found that the greatest difference between the H / W ratio is related to block A (0.54) and block H (1.98); this difference has caused that greatest difference between the maximum intensity of UHI would calculated between the two blocks equal to 5.2 degree.
Misconfiguration causes that energy leaving from city surface deal with the problem due to narrow passages and high buildings. Therefore, consideration appropriate width of passages and streets and height of buildings are necessary to ease heat leaving and reduce intensity of UHI.
These simulations showed that high buildings and narrow streets intensify the heat islands. While in the presence of short buildings and wide streets, the UHI max is lowered. When the ratio H / W in the studied urban area is between 0.54 to 0.81, UHI max remains between 5 to 6.6 C˚, when this ratio increases to 1.01 to 1.98, UHI max will be between 7.5 and 10.2 C˚. The result also revealed that block A and H with 5 and 10.2 C˚ have the minimum and maximum value of UHI intensity, respectively. So can be concluded that block A and H have the most standard and non-standard urban configuration in the region. The estimates from regression model showed that the street width (91.6%) is more effective than the height of the buildings (6.6%) in changing UHI max.
Fardin Saberi Louyeh, Bohlol Alijani, Shahriar Khaledi,
Volume 6, Issue 1 (5-2019)
Volume 6, Issue 1 (5-2019)
Abstract
. Caspian Sea south coast future climate change estimations through regional climate model
many physical of the procedures related to climate change are not perceived thoroughly. Scientific knowledge used to show those procedures completely, and to analyses forecasts is so complex, since most current studies about climate physical model have been done through semi experimental and random models and most of the current analysis techniques are still going through early stages. One of the important aspects of this study is modeling physical procedures of sea level rise geographical pattern, which is used practically for SLR threat evaluation of special geographical location, meaning Caspian basin. Since Caspian basin is a closed sea, it is heavily influenced by climate change and meanwhile is changing due to physical level and environmental change. It is necessary to define Caspian coast climate change possibility with specific focus on climatology and meteorology fine data, also to define the scale of sea level fluctuations for the sake of exact planning in different fields. This study aims at presenting a new dynamic method, via using an integrated model system named SIMCLIM, which can clarify SLR satellite changes well.
According to scientific examination existing in this study, based on scatter scenario 4.5 RCP and 8.5 RCP for the following years, until 2100, temperature and precipitation change proposal have been presented. On one hand, Caspian coastal climate change analysis and estimation were based on climate patterns and water flows in the form of regional climate statistical model in order to simulate and forecast, on the other hand surveying chronological changes of Caspian sea coast slope with satellite height measurement was done to measure sea surface height fluctuations The present study has used SIMCLIM model for the first time in order to clarify Caspian sea level changes, elements, and effective climate reasons, all simultaneously in one project. The project base is according to coastal systems and procedures. Coast line shore change simulations are based in Bruun law.
In future the frequency and intensity of extreme events temperature and precipitation will increase. Extreme events illustrate changes in extreme temperature and precipitation measures, in comparison with the base period of 1981-2010 which convey precipitation sum or the temperature beyond 95 percentile of base period. Temperature and precipitation coefficient of variation for the whole Caspian basin is positive and it varies from 25 to 88 percent. A disordered pattern is dominating south basin of the sea. Sea level changes, considering vertical earth movements, which is 2 mm in a year, resulted from subsidence of Caspian pit seabed have been obtained for both scenarios. In general, annual sea level average while ignoring seasonal changes, is increasing consistently and it was calculated 1.22 cm each year according to high estimation procedure in scenario 8.5 RCP and it was 0.93 cm based on scenario 4.5 RCP. Predicted results were compared with real results of base20-year period from 1995-2015. Base period results in three levels of sensitivity of low, mid, high shows 8.4, 10.1, and 11.8 cm rise; after comparing them with model forecast results, meaningful coordination at the level of 95 percent was found out. In both scenarios, all over the Caspian shoreline water advance and destruction will exist. In the worst case scenario of 8.5 RCP of 2030, current coast will decrease about 23 meters and in 2060 it will be about 53 and in 2100, there will be 117 meters advance towards land.
Precipitation and temperature percent for 2030, 2060, 2100 will change increasingly. Spatial variability and annul coefficient of variation are various in different regions. North, western north, eastern north and east will include the least temperature fluctuations, and the highest percent of precipitation with the highest coefficient of variation all convey chronological period precipitation distribution with disordered accumulation and more local difference in this region in comparison with other regions. Then Caucasus mountainous region will have the highest increase in precipitation with a suitable scatteredness, during a year. The southern part of Caspian Sea will be with the highest increase in temperature and the least amount of increase in precipitation in percent. High coefficient of variation in this area illustrates abnormal and disordered pattern on the threshold of precipitation for both scenarios.
fluctuations in sea level based on subsidence of Caspian pit seabed was calculated.In general, average annual sea level is increasing which will be 1.22 cm, per year for scenario RCP 8.5 and 0.93 cm for scenario 4.5. Due to incapability of world community in decreasing releasing greenhouse gases, it is expected scenario that 8.5 RCP to come to reality.
Caspian Sea shoreline is influenced by water advance and destruction. The difference between two scenarios in 2060 will be 3 meters and in 2100 will be 12 meters. Instinctually, such advances in coasts with less depth and less slope will be more. This study suggests that coastal changes are inevitable. However, this region inhabitant owns no systems or no systems have not yet developed to aid them be able to adopt with the climate changes.
Keywords: Sea level rise, South Caspian basin, Extreme event, Coefficient of variations, shoreline.
Ahmad Porahmad, Hossein Hataminezhad, Keramatollah Ziyari, Seaideh Alijani,
Volume 6, Issue 2 (9-2019)
Volume 6, Issue 2 (9-2019)
Abstract
A new Approach to Urban livability, Thermal Comfort as the Primitive Condition to enhance the livability: Case study, District 22 of Tehran.
Ahmad Porahmad: Professor of Urban Geography and Planning, University of Tehran
Hossain Hataminezhad: Professor of Urban Geography and Planning, University of Tehran
keramatollah Ziyari: Professor of Urban Geography and Planning, University of Tehran
Saeideh Alijani*: PhD candidate of Urban Geography and Planning, University of Tehran
The concept of urban livability is defined as the quality of life and wellbeing of urban residents. That is the interaction of people, environment and built environment. The residents can achieve happy life and well-being only when the nature surrounding them is happy and healthy. According to the range of welfare concept there is a spectrum of quantitative indicators that directly measure (human body temperature, heart rate, air temperature, wind speed ...) and qualitative indicators such as quality of life, pleasure and joy. The comfort and ease of environment are in the middle of the spectrum, in other words, the intrinsic concept of ambient comfort is environment. The inadequacy of natural environment will affect both indicators in the spectrum and lead to citizens' dissatisfaction and decline in social welfare and threaten the health of humans. Living in a salty marsh or very dry hot climate is never happy and satisfied. Accordingly, many concepts such as living quality, living environment, and quality of place, quality of life and sustainability are often used interchangeably with livability).
This research is trying to weight the natural environment at least equal to the other two components of the sustainable development triangle. Among the components of natural environment, climate is playing the most important and significant role. Urban climate affects all aspects of city including building interiors, city architecture and open spaces. Thermal comfort of open spaces promote the social life and interrelations of residents. Therefore, in order to promote the social relations and economic activities especial consideration should be paid to open spaces. Accordingly, two types of data were measured for calculating the thermal comfort in the district 22. Subjective and objective evaluations which present qualitative and quantitative data. Objective data includes micrometeorological measurements with mobile instruments. Subjective data evaluated actual sensation vote or perception vote of thermal comfort by people using the urban open spaces. To this goal, questionnaires were prepared and scattered through space users simultaneously with micrometeorological measurements. Subjective data evaluated perceptual sensation vote of thermal comfort by people using the urban open spaces in three hot days of August 2018. Nine points are selected for site measuring and field survey which are representative of two types of urban open spaces in this research:1) Urban park and 2) street. Four cardinal points were chosen adjacent to the Shohadaye Khalije Fars Lake inside the park located in sidewalk pathway around the Lake. Other five points were selected in streets with different orientation and aspect ratio through the district. The physiologically equivalent temperature (PET), mean radiant temperature (Tmrt), sky view factor (SVF) and aspect ratio (H/W) are the most important indicators in this research which were calculated for evaluating comfort in the district.
Results showed that urban open spaces in the district are discomfort and expose people to the extreme heat stress; over 40°C. This determines that, the natural environment especially around the Shohadaye Khalije Fars is not comfort. The questionnaire also indicated that people felt warm and dissatisfied.
There is a high linear correlation between thermal comfort and mean radiant temperature and globe temperature. Therefore, it is concluded that thermal comfort in the district, is directly affected by urban areas. Also in the streets with low SVF and high aspect ratio, PET were calculated more comfortable than other streets. Point 5 at Naghibzade street, confirmed the effect of urban geometry on thermal comfort. Otherwise, the lack of tremendous trees for creating shade is visible especially around the lake. The high linear correlation between Tmrt and SVF around the lake confirmed the openness of the area and the high amount of solar radiation. Therefore, planting more trees for creating the shade effect is necessary.
The perceptual analysis of thermal comfort indicated that by increasing of PET, people felt warmer. However, in a city like Tehran, people are more resistance to the heat stress. In addition, the characteristics of human body strongly depends on psychology and individual features and is a hard issue to predict. Otherwise, the people who felt warm were more than those felt slightly warm which indicates dissatisfaction of people. To be noticed that, thermal comfort of above 40 °C in summer is an alarm to urban planner and designers to rethink about climate consideration and global warming as a most important urban challenge in the district seriously. Besides, the consideration of thermal comfort and urban geometry should be imbedded into the comprehensive plan. This research proved that the climatic consideration for improving the quality of life and livability is important and urban designers and planners should rethink and review the comprehensive plan of Tehran to make a livable and sustainable city in the future.
Keywords: urban livability, climate comfort, sustainable development, urban sustainability, urban geometry, physiologically equivalent temperature, district 22 of Tehran.
Nima Sohrabnia, Dr Bohlol Alijani, Dr Mehry Akbari,
Volume 7, Issue 2 (8-2020)
Volume 7, Issue 2 (8-2020)
Abstract
Modeling the discharge of rivers in selected watersheds of Guilan province during climate change
Abstract
In this essay, we investigated the effects of climate change on the rivers of selected basins of Guilan province, one of the northern provinces of Iran for the period 2020 to 2050 under three climate scenarios: RCP2.6, RCP4.5, RCP8.5. For this purpose, rainfall and temperature data from 45 climate data stations and 20 hydrometric stations from 1983 to 2013 were used. The average precipitation and temperature at basin level were calculated by drawing both Isohyet and Isothermal lines by usage Kriging method. Mann-Kendall and Sen’s slope estimator tests were used to determine the significance of the data trends and their slope, respectively. The results showed that temperature has increased in all catchments during the study period and this trend was significant in most of them but no significant trend was observed for precipitation. Discharge has also decreased in most basins and this trend was significant in Shafarood, Navrood and Chafrood basins. However, for future periods, precipitation is not significant in any of the climate scenarios, but the temperature is increasing in all scenarios except for the RCP2.6 scenario. Rivers discharge in the RCP2.6 scenario is not significant in any of the basins, but in the RCP4.5 scenario the Shafarood and Ghasht-Roodkan catchments have a significant reduction in the 95% confidence level. In the RCP8.5 scenario, the Chafrood and Shafarood basins have a 99% confidence reduction trend.
Population and technology growth, increased water consumption and climate change have led many researchers to study and model water resources in the present and future periods. Especially in areas like Iran that are facing a lot of water stresses. The purpose of the present study, which was carried out in the Guilan province, is to provide information on the present and future status of surface water resources, and to prepare them for facing the problems of potential water resources exploitation.
In this study 45 synoptic, evaporative and rain gauge stations and 20 hydrometric stations data with sufficient statistics were used. The period of study is also between 1983 and 2013. In this regard, after calculating the average precipitation and temperature values of each basin using Kriging model, first, the annual average of precipitation and temperature values of each basin were calculated. Then, multivariate regression was used to obtain the regression equations between precipitation, temperature and discharge data, then by using SDSM model and climate scenarios (RCP2.6, RCP4.5, RCP8.5) future temperature and precipitation data were generated. By placing these generated data in the Created regression equations, the discharge of the rivers was calculated for the period 2020 to 2050. The trend of time series and their slope were analyzed respectively by Mann-Kendall and Sense tests.
The study of the annual average precipitation trend of the selected catchments during the study period showed that all the basins had no significant trend at any of the confidence levels (95% and 99%). However, for the temperature there is an increasing trend. In Chafrood, Zilaki, Chalvand, Lavandevil, Tutkabon, Chubar, Lamir, Hawigh, Dissam, Shirabad, Ponel, Samoosh, and Polrood basins there is significant trend at 95% confidence level. For the Hawigh River basin there is significant trend at 99% confidence level. Also in most of the basins there is a downward trend of rivers discharge. In addition, in the three basins of Chafrood, Navrood and Shafarood, there is a significant decreasing trend at 95% confidence level, which is also significant at 99% confidence level for Navrood and Shafarood rivers.
Analysis of future data showed that precipitation is not significant in any of the climate scenarios, but the temperature is increasing in all scenarios except for the RCP2.6 scenario in RCP2.6 scenario. For rivers discharge there was no significant trend in any of the basins, but in RCP4.5 scenario there is a significant decrease in 95% confidence level in Shafarood and Ghasht-Roodkan. Also in the RCP8.5 scenario, a significant decreasing trend of flow discharge at 99% confidence level is observed for Chafrood and Shafarood basins. Finally, the catchments were grouped according to the level of risk involved with decreasing discharge. The results of grouping showed that most of the basins in the three scenarios were in the medium risk group but Shafarood, Chafrood and Ghasht-roodkhan watersheds have higher risk than the other watersheds, respectively.
Investigation of river discharge trends for the period 2020 to 2050 in different scenarios showed that the basins of Ghasht-roodkhan, Chafrood and Shafarood are more sensitive to climate change than other basins. Overall, escalating temperature trends in future and precipitation irregularities can create very difficult conditions in future to use these resources. Especially, this study's concordance with other studies in Iran and the study area confirms that such crises are more likely to occur..
Keywords: Climate Change Scenarios, Rivers Discharge, Man-Kendall, Sen’s Slope estimator, Guilan Province
Abstract
In this essay, we investigated the effects of climate change on the rivers of selected basins of Guilan province, one of the northern provinces of Iran for the period 2020 to 2050 under three climate scenarios: RCP2.6, RCP4.5, RCP8.5. For this purpose, rainfall and temperature data from 45 climate data stations and 20 hydrometric stations from 1983 to 2013 were used. The average precipitation and temperature at basin level were calculated by drawing both Isohyet and Isothermal lines by usage Kriging method. Mann-Kendall and Sen’s slope estimator tests were used to determine the significance of the data trends and their slope, respectively. The results showed that temperature has increased in all catchments during the study period and this trend was significant in most of them but no significant trend was observed for precipitation. Discharge has also decreased in most basins and this trend was significant in Shafarood, Navrood and Chafrood basins. However, for future periods, precipitation is not significant in any of the climate scenarios, but the temperature is increasing in all scenarios except for the RCP2.6 scenario. Rivers discharge in the RCP2.6 scenario is not significant in any of the basins, but in the RCP4.5 scenario the Shafarood and Ghasht-Roodkan catchments have a significant reduction in the 95% confidence level. In the RCP8.5 scenario, the Chafrood and Shafarood basins have a 99% confidence reduction trend.
Population and technology growth, increased water consumption and climate change have led many researchers to study and model water resources in the present and future periods. Especially in areas like Iran that are facing a lot of water stresses. The purpose of the present study, which was carried out in the Guilan province, is to provide information on the present and future status of surface water resources, and to prepare them for facing the problems of potential water resources exploitation.
In this study 45 synoptic, evaporative and rain gauge stations and 20 hydrometric stations data with sufficient statistics were used. The period of study is also between 1983 and 2013. In this regard, after calculating the average precipitation and temperature values of each basin using Kriging model, first, the annual average of precipitation and temperature values of each basin were calculated. Then, multivariate regression was used to obtain the regression equations between precipitation, temperature and discharge data, then by using SDSM model and climate scenarios (RCP2.6, RCP4.5, RCP8.5) future temperature and precipitation data were generated. By placing these generated data in the Created regression equations, the discharge of the rivers was calculated for the period 2020 to 2050. The trend of time series and their slope were analyzed respectively by Mann-Kendall and Sense tests.
The study of the annual average precipitation trend of the selected catchments during the study period showed that all the basins had no significant trend at any of the confidence levels (95% and 99%). However, for the temperature there is an increasing trend. In Chafrood, Zilaki, Chalvand, Lavandevil, Tutkabon, Chubar, Lamir, Hawigh, Dissam, Shirabad, Ponel, Samoosh, and Polrood basins there is significant trend at 95% confidence level. For the Hawigh River basin there is significant trend at 99% confidence level. Also in most of the basins there is a downward trend of rivers discharge. In addition, in the three basins of Chafrood, Navrood and Shafarood, there is a significant decreasing trend at 95% confidence level, which is also significant at 99% confidence level for Navrood and Shafarood rivers.
Analysis of future data showed that precipitation is not significant in any of the climate scenarios, but the temperature is increasing in all scenarios except for the RCP2.6 scenario in RCP2.6 scenario. For rivers discharge there was no significant trend in any of the basins, but in RCP4.5 scenario there is a significant decrease in 95% confidence level in Shafarood and Ghasht-Roodkan. Also in the RCP8.5 scenario, a significant decreasing trend of flow discharge at 99% confidence level is observed for Chafrood and Shafarood basins. Finally, the catchments were grouped according to the level of risk involved with decreasing discharge. The results of grouping showed that most of the basins in the three scenarios were in the medium risk group but Shafarood, Chafrood and Ghasht-roodkhan watersheds have higher risk than the other watersheds, respectively.
Investigation of river discharge trends for the period 2020 to 2050 in different scenarios showed that the basins of Ghasht-roodkhan, Chafrood and Shafarood are more sensitive to climate change than other basins. Overall, escalating temperature trends in future and precipitation irregularities can create very difficult conditions in future to use these resources. Especially, this study's concordance with other studies in Iran and the study area confirms that such crises are more likely to occur..
Keywords: Climate Change Scenarios, Rivers Discharge, Man-Kendall, Sen’s Slope estimator, Guilan Province
Bohloul Alijani,
Volume 7, Issue 4 (2-2021)
Volume 7, Issue 4 (2-2021)
Abstract
Abstract
Corona Virus pandemic outbreak is the counter act and warning of the natural environment for the destructive activities of man in the nature. Many researchers and specialists believe that a risk free and sustainable life is possible if we correct our behavior toward the nature. This research was carried out to substantiate this hypothesis and offer a reasonable and rationale solution. It is believed that the best way to solve this problem is the environmental ethics. Many other ways such as technology have been proposed, but until the mind and thought of man has not changed to good relation with the nature, it is not possible to reach a viable solution. For this end, the integrated system of earth was analyzed to understand mechanism of the relation between nature and human. Two supportive theories of Markov Blanket and Gaia were addressed here to explain the relation between nature and society. According to these theories the system of earth and society is live and any change in one will mirror itself on the other. As a result, the society models itself to the nature in long run. This means that to have a healthy society we should have a healthy nature and environment. Thus, the UNEP has suggested the integrated One Health program to save nature, humans and animals at the same time.
The distortions of the earth during the past 70 years were sampled and described as the footprints of mankind. Some examples of environmental disorders such as climate change, droughts, floods and diseases were analyzed and their impacts on the society were displayd. In order to demonstrate the environmental ethics as the only solution to the current crises, first the ethics in general were discussed and then the environmental ethics were given a thorough explanation. Different underpinning philosophies are presented and accordingly different approaches to the nature such as development, preservation and conservation were discussed. A new philosophy, geocentrism, was suggested as the suitable and efficient thought. According to this philosophy it is the distributions which are in the forefront of human destruction. Therefore, we should try not to disturb the distributions of any kind. These include all ecosystems of any scale; because emphasizing on the ecosystems is not sufficient. The geocentrism philosophy covers all non - anthropocentrism philosophies such as biocentrism and ecocentrism. Of the different approaches, the conservation was selected as it assumes intrinsic value for the nature and sustainability of resources for ever.
To solve the problem and bring the earth system to sustainable state, the environmental ethics should be implemented. In terms of moral values, these include truth, good, duty and justice. The mankind should characterize himself with these genuine characters. He should do his duty as not making problem to the life of any creature; this being human, plant, animal or rock and soil and etc. He should do the good and justice. On the objective side, he should give intrinsic value for every creature on the earth including the environment and its components. In this way, we treat the environment with respect and dignity and not let ourselves to destroy or damage it. However, to achieve these goals we should use resources only as much as we need biologically, consider the long run benefits instead of short term benefits, treat the nature as having intrinsic value, implement the environmental distance from wild life, using vegetarian diet.
One important notice is the nature of human who we are asking to do these mandatories. Are we sure that what we are ordering human will be done by him. If he does not do then none of these comments is valuable. Therefore, we first should understand the humans and educate them to accept our orders. This is why that the ethics become important. We should train moral humans and then ask them to do. He will do only when he gets overarching and believed knowledge about the subjects we are offering. The main reason for the distortion of the nature is that the humans are not aware of the value of nature and the long run results of their actions. This is possible only through the good and responsible training of man. We are now missing this education. In brief, we understand that the main solution for the destruction of nature is empowering the humans with morals, especially environmental ethics. But to implement this objective, at the first point we need a wise and understandable human. Therefore, first we should train people and ask them to act as a moral and generous person and care for the nature and all creatures of the universe.
The distortions of the earth during the past 70 years were sampled and described as the footprints of mankind. Some examples of environmental disorders such as climate change, droughts, floods and diseases were analyzed and their impacts on the society were displayd. In order to demonstrate the environmental ethics as the only solution to the current crises, first the ethics in general were discussed and then the environmental ethics were given a thorough explanation. Different underpinning philosophies are presented and accordingly different approaches to the nature such as development, preservation and conservation were discussed. A new philosophy, geocentrism, was suggested as the suitable and efficient thought. According to this philosophy it is the distributions which are in the forefront of human destruction. Therefore, we should try not to disturb the distributions of any kind. These include all ecosystems of any scale; because emphasizing on the ecosystems is not sufficient. The geocentrism philosophy covers all non - anthropocentrism philosophies such as biocentrism and ecocentrism. Of the different approaches, the conservation was selected as it assumes intrinsic value for the nature and sustainability of resources for ever.
To solve the problem and bring the earth system to sustainable state, the environmental ethics should be implemented. In terms of moral values, these include truth, good, duty and justice. The mankind should characterize himself with these genuine characters. He should do his duty as not making problem to the life of any creature; this being human, plant, animal or rock and soil and etc. He should do the good and justice. On the objective side, he should give intrinsic value for every creature on the earth including the environment and its components. In this way, we treat the environment with respect and dignity and not let ourselves to destroy or damage it. However, to achieve these goals we should use resources only as much as we need biologically, consider the long run benefits instead of short term benefits, treat the nature as having intrinsic value, implement the environmental distance from wild life, using vegetarian diet.
One important notice is the nature of human who we are asking to do these mandatories. Are we sure that what we are ordering human will be done by him. If he does not do then none of these comments is valuable. Therefore, we first should understand the humans and educate them to accept our orders. This is why that the ethics become important. We should train moral humans and then ask them to do. He will do only when he gets overarching and believed knowledge about the subjects we are offering. The main reason for the distortion of the nature is that the humans are not aware of the value of nature and the long run results of their actions. This is possible only through the good and responsible training of man. We are now missing this education. In brief, we understand that the main solution for the destruction of nature is empowering the humans with morals, especially environmental ethics. But to implement this objective, at the first point we need a wise and understandable human. Therefore, first we should train people and ask them to act as a moral and generous person and care for the nature and all creatures of the universe.
Key words: Corona Virus, Covid-19, sustainability, environmental ethics, human-nature relation, Markov Blanket, natural resources, UNEP One Health program, Gaia, Anthroposcene.
Professor Bohloul Alijani,
Volume 8, Issue 3 (12-2021)
Volume 8, Issue 3 (12-2021)
Abstract
Geography and the Paradigm of Sustainable Development
Extended Abstract
Geography and sustainable development
The relation between society and environment has gone through different phases. During the years before the World War II, the environmental determinism controlled this relation. However, after the 1950’s the anthropocentrism replaced the environmental determinism and humans began to overuse the nature in such a way that nature lost its sustainability and many hazards and crises occurred. These destructions were so intense and widespread that some researchers compared with the episodes of geologic time and named the era beginning from 1970’s the Anthropocene epoch. During this period, the planetary boundaries were crossed in some areas such climate change, nitrogen cycle and biodiversity. Climate change has created most of other hazards.
To overcome these problems in 1978 the Brandtland report announced the sustainable development as not to spend resources more than the nature’s production capacity and not to pollute the nature more than it can assimilate. In other words, the nature should remain in its sustainable state so that the future generations can live with no limitations. The principles of the sustainable development were defined in the earth summit of Rio in 1992 such as social equity, economic viability, and environmental sustainability. These principles were broken down in 17 goals. The Rio conference asked all countries to achieve the sustainable development goals by 2030.
Methodologically the sustainable development requires integrated multidisciplinary approach to investigate the complex system of human- environment in different temporal and spatial scales to achieve the social equity, economic viability, and environmental sustainability. For this reason, many disciplines such as natural resources, environmental sciences, ecology and geography have contributed to the field. Different data from natural resources, human needs and drivers and environmental changes are required to process in very complicated models. In addition to different variables, the hazards are very important component of the sustainable development research, which also requires multi-aspect complicated approach and models. Spatial dependency is another aspect of sustainable development as it differs from place to place in many characteristics. In brief, from the spatial perspective the sustainable development is an integrated multi-approach research about the human-environment system to establish the sustainability on the earth. All of the related fields should study the sustainable development in collaboration with each other. However, the geography due to its long history of studying the relation between human and environment and its spatial dependency is the best single scientific field which can afford studying the sustainable development. Since the earliest times geography has developed quantitative methods, spatial techniques such as geostatistics, and environmental ethics to conserve the nature and human prosperity. The multi approach and systematic works are the main characteristics of Geography. On the other hand, Geography’s vision of defining the location for human’s activities while saving the nature’s sustainability covers the sustainable development completely. Therefore, geography is the overarching field for the sustainable development and it is the main intention of geographers to research and implement the sustainable development to reduce the environmental hazards and develop the sustainable environment for all the human beings at present and in the future. Geography studies the sustainable development through three steps including spatial analysis, spatial planning, and spatial management. In addition, geographers should learn different skills such remote sensing, multivariate statistics and above all develop a common language between different branches of geography.
Keywords: geography, sustainable development, environmental ethics, human nature relationship, Anthropocene, planetary boundaries, sustainability.
Mrs Fatemeh Falahati, Dr Bohlol Alijani, Dr Mohammad Saligheh,
Volume 8, Issue 4 (1-2021)
Volume 8, Issue 4 (1-2021)
Abstract
In many areas, snow cover in the mountains is a major source of surface and underground water supply. Due to climate change and its effect on the time of melting ,it is very important for environmental planning to predict the arrival time of water from snow melt to water consumption cycle. The purpose of this study is to investigate the volumetric changes and time distribution of snow flood flows in future by integrating remote sensing , GIS and climatic models.The studied area is the Upper Basin of Amir Kabir Dam, which is located on the southern slopes of Alborz Mountains. In this study, digital elevation maps (DEM) and GIS software were used to estimate parameters such as area, environment, main length, highest and lowest elevation points. In order to complete the snow cover data, MODIS products (MOD10A100) were extracted and the snow cover was extracted in the Upper Basin of Amir Kabir Dam. Next, runoff and snow melting models were simulated using SRM software. Calibration and validation of the model's acceptable performance were estimated. Then, in order to investigate the effects of climate change on the future of snowmelt runoff production in the basin of Amir Kabir Dam, the latest CMIP5 climatic models were used under four scenarios RCP2.6, RCP4.5, RCP6.0 and RCP8.5. A survey on the relationship between snow cover area , temperature and precipitation was used to predict snow cover in the future. The increase in temperature in the autumn and winter season has led to a reduction in the shape of precipitation in the form of snow, and as a result, the amount of snow storm is reduced. The results show that the amount of runoff in the autumn and winter increases due to increased rainfall in the form of rain, and it will be increased late winter and spring due to the increase in the amount of water resulting from snow melting. The results of this study are based on the increase of snow melt as a result of increased runoff volume, reduction of snow reserves and maximum flow transmission to earlier than normal conditions due to early snow melting due to temperature rise. Generally, in the future, the average annual runoff will be decreased about 1.1 cubic meters per second, and the average annual melting share will be about 13.9%
- Mahmoud Roshani, - Mohammad Saligheh, - Bohlol Alijani, - Zahra Begum Hejazizadeh,
Volume 8, Issue 4 (1-2021)
Volume 8, Issue 4 (1-2021)
Abstract
In this study, the synoptic patterns of the warm period of the year that lead to the cessation of rainfall and the creation of short to long dry spells were identified and analyzed. For this purpose, the rainfall data of 8 synoptic stations were used to identify the dry spells of the warm season for 30 years (1986 to 2015). The average daily rainfall of each station was used as the threshold value to distinguish between wet and dry spells. Then, according to the effects of dry spells, they were defined subjectively and objectively with different durations. Thus, 5 numerical periods of 12 to 15, 15 to 30, 30 to 45, 45 to 60 and more than 60 days were identified. By factor analysis of Geopotential height data at 500 hPa, 4 components were identified for each period and a total of 20 components for 5 dry spells. Therefore, 5 common patterns control the stable weather conditions of dry spells. Most dry days are caused by subtropical high-pressure nuclei, which have a wide, even, dual-core, triple-core arrangement. The effect of subtropical high pressure on the dryness of the southern coast of the Caspian Sea is quite evident. Other dry days were caused by southerly currents, weakening of northern currents, and the trough Anticyclones’ area. Also, the anomaly map of the components days at the 500 hPa level showed that the anticyclones and cyclones correspond to the positive and negative phases of the anomalies, respectively.
Ms Mahsa Sepasian, Dr. Bohloul Alijani, Dr. Mohammad Salighe, Dr. Mehry Akbary,
Volume 8, Issue 4 (1-2021)
Volume 8, Issue 4 (1-2021)
Abstract
Tehran metropolitan with its large population, daily migrant workforce and many students, needs to planning and designing watch/warning system to reduce the climatic problems for human health.for this purpose, we need to study the climate accurately and Since the factors affecting the climate of warm and cold periods in Iran are different, in this study , the meteorological variables of Tehran warm period (May to September 2002) turned into 4 components in Temporal Synoptic Index (TSI) using PCA Method and using P-Array and Varimax rotation.By the scores of components for each day, the clustering method (in ward method) were used and, the warm days of the year was divided into two cluster named favorable and oppressive airmasses. The average maximum air temperature that is more effective in mortality, was 36.13 ° C. Days with temperatures above 34 ° C, less pressure, mild winds , dryness and more sunshine resulted in more adverse weather conditions, which resulted in a 34% increasing in mortality compare with favorable weather. The total number of deaths from cardiovascular disease during the study period was 154046 that about 67%of deaths have been simultaneous with oppressive airmass.The epidemiological study of mortality also confirms the results of previous research in this area and shows that the incidence of mortality is higher in older people as well as in men. It is clear that not all mortality can be attributed to the effects of climate, but results show that change in climatic conditions will affect on mortality and also for study the effect of climatic hazards on human health, it is better that we study the effect of all variables together on humans.
Fatemeh Arsalani, Bohloul Alijani, Sabereh Arsalani,
Volume 8, Issue 4 (1-2021)
Volume 8, Issue 4 (1-2021)
Abstract
Dust fall means the dust that in the air fall down on the ground (Hai et al, 2008). it is important to study the extent of heavy metal contamination of dust fall due to their threats that could affect human health. Due to the fact that the metropolis of Tehran has a population of over eight million people and One of the major cities in the world is currently facing a severe air pollution problem. The purpose of the present study was to determine the level of pollution and health risk of heavy metals such as Cd, Cr, Cu, Ni, Pb in the dust falling of Tehran city. the Dust fallout samples were collected using Marble Dust Collector (MDCO) from 28 different locations across Tehran during the statistical period (2018/03/21- 2018/06/21). We used XRF analysis To identify and determine the concentration of heavy metals (Cd,Cr,Cu,Ni,Pb,Fe) in the collected dust. we used to spatial analysis to determine Dispersion of pollution levels and health risk in different Zone of Tehran city. In order to determine the level of pollution and Health Risk Assessment we used the pollution index (PI), integrated pollution index (IPI), Non-Carcinogenic Risk and Carcinogenic Risk. Based on the results of the calculations performed in the statistical period studied, the values of pollution index (PI) and integrated pollution index (IPI) are Pb> Cd> Cu> Cr> Ni, respectively. Accordingly, the regional trend of pollution from west to east is increasing. Therefore, Tehran's pollution index is high level of pollution in the most zone and and extremely high level of pollution in the eastern zone, which is a more worrying situation. Probably one of the reasons is the western winds, which are faster in the west than in the east. Also, Tehran's topographic pattern plays a role in this issue. Health risk assessment (HQ, HI, CR) showed that the contamination of the heavy elements studied was lower than the acceptable threshold for carcinogenic and non-carcinogenic risks. Therefore, it is not dangerous in terms of carcinogenicity. The risk of carcinogenicity and non-carcinogenicity in children and adults is higher in the southern and eastern zone of Tehran. Probably one of the reasons is the establishment of metal industries, cement production, sand mines and combustion processes in the south and west of Tehran metropolis.
Phd Bohloul Alijani, Phd Mohammad Hosein Naserzadeh, Phd Hasan Ghazi, Mohammad Mohammadi,
Volume 8, Issue 4 (1-2021)
Volume 8, Issue 4 (1-2021)
Abstract
Combat readiness in military units indicates the ability of the unit to perform military missions. To conduct research and extract weather threats in the southeastern region, data from 19 synoptic stations with a statistical period of 22 years were used and to prioritize weather threats, combat readiness criteria were used. Dust storms, heat stress, heavy rainfall and sultry conditions were identified as the most important weather threats affecting combat readiness in the region. Based on the hierarchical analysis of dust storms, the most important and effective threat to the combat readiness of military units was identified, the incompatibility rate was calculated and its value was less than 0.1, so pairwise comparison, weighting and prioritization of threats were confirmed. The zoning map of each weather threats was prepared in GIS software and finally, using the weight of each weather threats, it was obtained by combining the zoning maps of the identified threats and using fuzzy hierarchical analysis, a comprehensive map of weather threats was prepared. Zabol and Zahak synoptic stations in spring, the whole region in summer, Saravan station in autumn and Iranshahr, Saravan, Minab and Kahnooj stations in winter are the worst places for military units and also in autumn the lowest frequency of hazards in the region. We witnessed and based on weather maps, this season was recognized as the best season for the deployment and operation of military units in the region.
Sharifeh Zarei, Bohloul Alijani, Zahra Hejazizadeh, Bakhtiar Mohammadi,
Volume 8, Issue 4 (1-2021)
Volume 8, Issue 4 (1-2021)
Abstract
In this research, the most important synoptic patterns of widespread snowfall in the western half of Iran have been investigated. For this purpose, the data of current weather code and snow depth of 36 synoptic stations during the statistical period of 1371-1400, for the months of October to March, were received from the Meteorological Organization of the country. In order to investigate wide snowfalls, the days when more than 70% of the studied area saw snowfall at the same time were extracted as a wide day. In order to perform synoptic-dynamic analysis of wide snowfalls in the western half of Iran, the classification method using cluster analysis was used and maps of representative days were drawn, including atmospheric temperature, moisture flux, geopotential height, tovai, front formation, jet stream, omega index, and orbital and meridian wind data. Trend analysis was also performed using the Mann-Kendall test. The results showed that 4 models justify the widespread snowfall in the studied area in the best way. According to the results in all the models, at sea level, the collision of cold and dry air of northern latitudes with warm and humid air of southern latitudes has caused the formation of frontal fields in the western half of Iran. At the level of 500 hectopascals, the intensification of the meridional currents in the western winds caused the creation of closed centers and as a result the flow changed in the direction of the westerly winds, and the location of the western half of Iran in the east of Naveh Al-Aghti and Sardchal has provided the necessary conditions for air to rise. Also, there was no trend in the number of snow days in the western half of Iran at the significant levels tested. But; The number of snow days has been decreasing over time. In general, it can be concluded that due to the warming of the earth and climate change, the number of snowy days has decreased and these changes have led to a significant shortening of the snow season.
Mrs Masoumeh Alidadi, Professor Bohlol Alijani, Dr Mohammadhossein Nasserzadeh, Professor Zahra Hejazizadeh,
Volume 9, Issue 1 (5-2022)
Volume 9, Issue 1 (5-2022)
Abstract
Comparative analysis of snowfall events in Iran with emphasis on the location of the polar plateau and remote connection patterns
Abstract
Extream snowfall event that may occur at any time during the cold season, has significant social and economic implications. Therefore, the economic and social consequences of these events reveal the importance of identifying the synoptical mechanisms associated with the extream snowfall events. In order to achieve this goal, using daily precipitation and temperature data during the statistical period of 1951-1 2016 and based on multiple criteria, the two three-days extream snowfall events were identified during February 7-9, 1972 and February 2-4, 1988. After selecting samples, a statistical analysis of the teleconnection indices was done and then, using the NCEP-NCAR reanalysis data, the combined patterns of surface and lower, middle and lower troposphere were plotted in the form of three-days mean. Results obtained from analysis of teleconnection indices and their correspondence to the synoptic patterns indicate the weakening of the tropospheric polar vortex and its division into multi-centers in the periods of extream snowfall events. In the event of February 7-9, 1972, though the centers were moved to mid-latitudes, but they are not completely out of the Arctic and to some extent maintain their position in this area. In February 2-4, 1988, the vortex centers have shown a more equatorwards displacement towards the mid-latitudes that the emergence of negative phases of the NAM and AO represent such a situation. However, in both events, the strong and main center of the polar vortex is located in the eastern hemisphere and therefore in a state close to Iran. The weakening of the sub-tropical jetstream in the eastern hemisphere, especially in the Mediterranean, has resulted in the transmission of potential vorticity tabs to mid-latitudes. The equatorwards progress of these tabs has led to the formation of the trough in the western and eastern Mediterranean regions that accompany with a ridge between them, led to the formation of omega bundle patterns and split flow, respectively, in the events of February 1972 and 1988 in this geographical area. The southern boundary of the progress of the troughs has specified by index contour of the edge of the vortex by 552 gpdam, that extends to the southern part of Iran and in the February 1972, event compared with the pattern of the February 1988, had the more-equatorwards progress toward the middle latitudes, and as a result, over Iran.
Keywords: extream snowfall event, teleconnection, polar vortex, the edge of the vortex, blocking patterns.
Rasool Nooriara, Seysd Jamalaldin Daryabari, Bohlol Alijani, Reza Borna,
Volume 9, Issue 3 (12-2022)
Volume 9, Issue 3 (12-2022)
Abstract
Synoptic analysis of the torrential on Day 21, 1398 (Case study: Zahedan and Qeshm) Abstract Rainfall is the most important phenomenon or feature of the environment and so far many studies have been done about its causes. In any place, rainfall occurs when humid air and climbing cause are provided. Both of these conditions are provided by the circulation pattern. The study area is affected by some severe and sudden weather phenomena such as low annual rainfall, short rainfall period and rainfall in the form of heavy showers. Thus, it is possible that the limited and pervasive precipitation of the area is due to a different synoptic pattern. Because the relationship between circulation patterns and precipitation is significant, achieving acceptable results in the field of the relationship between these patterns with the limit and total rainfall of the studying area requires the analysis of synoptic maps. Therefore, the most important purpose of the present study is the synoptic analysis of heavy cloud rainfall of the studying area on Day 1398. Two sets of data were required for this study: A: Daily precipitation data of study stations on the day of heavy cloud rainfall on 21 Day (January 11, 2020) along with daily precipitation data in the days before the flood (96 hours before the flood) which was received from the main Meteorological Organization of the country. B: atmosphere data levels including: sea level (SLP), 850 and 500 hPa levels, vertical atmospheric velocity and wind flow levels of 1000, 850 and 500 hPa, specific humidity of 1000 and 700 hPa levels and 250 hPa surface flow winds for study days from the US National Center for Environmental Forecasting / National Atmospheric Research Center (NCEP/NCAR) were provided in the range of 0 to 60 degrees at north latitude and 0 to 80 degrees at east longitude, and finally, maps were drawn and prepared in Gardes software to provide the ability to interpret. The synoptic analysis of sea level showed that: on the day of the heavy cloud, a low-height closed center with a central core of 1,010 hPa in the northeast-southwest direction covered the entire study area. Then, the high-height with a central core equal to 1030 hPa is located at northwest of Iran, northwest of Europe and on Tibet. According to the location of high-pressure dams around Iran and the location of low-pressure centers on the study area and water resources in the south, a strong pressure has been created. Subsequently, with height increasing, low-height with central core equal to 1440 geopotential meters is located at northeast-southwest direction of entire study area. And the low height of northern Russia extends to the Persian Gulf and provides the conditions for severe ascent and instability in a very large area. The rear dams of Nave transferred the cold air of the high latitudes into the bottom of the Nave located on the study area and have intensified the instability. Also, the geopotential height of 500 hPa level of deep descent is located at the northeast-southwest direction of Iran and core of the Nave covers the Persian Gulf completely, that is the study area in the best condition and in front of the Nave, which is diverged by hot and humid weather. This deepening of the rotation and the penetration of the Nave to the lower latitudes caused the cold air to fall. The analysis of the 250-hectopascal-level flow-wind shows that the flow-wind with a core speed of 65 meters per second has covered the entire study area by crossing above the Persian Gulf, and compared to the previous days, the flow-wind is completely meridional. Synoptic analysis of the vertical velocity at the level of 1000 hPa shows that the maximum negative omega -0.2 to -0.15 Pascal per second in the northwest-southeast direction has covered the study area. The presence of negative omega index values indicates the role of convection in intensifying precipitation in mentioned area and the dynamic ascent of air. The study map shows that compared to other countries in the study map, the maximum of negative omega is located on Iran, which is reduced along to the west of Iran. With increasing altitude, the maximum negative omega has increased to -0.3 Pascal per second and the core of the maximum negative omega is completely located on the study stations (Zahedan and Qeshm). Then, at the level of 500 hPa, the maximum negative omega has reached -0.6 Pascal per second and its value has doubled compared to the level of 850 hPa, which covers the northeast-southwest direction from Zahedan to the Strait of Hormuz. Cold air fall has increased with increasing of omega levels in the middle levels of the atmosphere.In other words, in the middle levels of the atmosphere, with increasing temperature difference between the earth's surface and the level of 500 hPa, the amount of precipitation has increased. Synoptic analysis of specific moisture level of 1000 hPa shows that the most moisture deposition was from south water sources to the study area, and the amount of moisture equal to 14 grams per kilogram has entered the study area from the Oman Sea and then its amount has been reduced crossing to other regions of Iran. Furthermore, at the level of 700 hPa, the maximum advection of hot and humid air is in front of the upper atmosphere of Nave from the Red Sea over the study area. There is a moisture strip from the southeast to the whole area under analysis. These suitable humidity conditions with the depth of the western wave have been able to cause heavy cloud rainfall. The maximum amount of moisture in the study area is equal to 7 grams per kilogram, which is a large amount compared to heavy rainfalls. Keywords: heavy rainfall, flood, synoptic, Zahedan, Qeshm
Prof Bohloul Alijani,
Volume 10, Issue 1 (5-2023)
Volume 10, Issue 1 (5-2023)
Abstract
Abstract
During the recent decades the discipline of geography has lost its priority and position to some degree in Iran. Most of the graduates could not enter into the work in the universities and other organizations. The human-environment system, the main area of geographical specialty - has experienced many crises and hazards among which the global warming and climate change being the most destructive. This means that the ongoing curriculum is not working well and needs to experience a fundamental change. To implement this operation some points should be cleared out: The hazardous condition of the world and especially Iran, the education history and state of geography in Iran, and the relation between geography and sustainable development of the world. The discipline of geography has changed its approach according to the circumstances of each period several times. For example, at the beginning of the twenty-century due to the dominance of the environmental determinism, the dominant approach of geography was the relation between man and environment. But since the 1970’s the earth has encountered with different hazards and crises to the extent that it is named as the period of Anthropocene. Accordingly, the dominant approach of geography during this Anthropocene era is to identify and solve the hazards and crises and lead the man- environment system towards the sustainability as once was requested by the secretary general of the United Nation. In this regard the geography should adopt the sustainable development concepts and goals. For this reason, the geography of Iran should make a switch from its very specialized approach to a relatively wholistic view and pay more attention to the human- environment paradigm. To implement this order, the following assumptions should be considered.
- The applied objective of the discipline should be defined as “locating the suitable place for the living and activities of man without endangering the sustainability of the natural environment. This objective is not clear at the present curriculum. Defining this objective will clearly show students what is their job after finishing the career.
- The main vision of geography education is the creation of the sustainable geographical space or environment.
- The research approach is problem solving. Because most of the laws and concepts are identified and defined. Due to the hazardous nature of the earth system geographers should identify the problems and research to solve them via geographical thought and knowledge.
- The terrestrial unit for working is region. This is very important concept in geography. We cannot prescribe one sustainability procedure for all of the world. But we do one for each region. When regions became sustainable, all the world will be sustained.
- In any region the hazards and crises will be identified and described through the spatial analysis methods and will be conducted towards sustainable human – environment system. This monitoring is composed of the stages of spatial analysis, spatial planning, and spatial managing.
- All of the geography subjects and materials are necessary for sustainable development goals. The only criteria will be added is the environmental ethics in all of the geography activities and applications.
- Instructors and students should be familiar with the techniques of integration and multi-dimension modelling.
- All geography graduates will respect the nature and its resources and should consider the environmental ethics during their academic career. They should be able to identify and solve the environmental problems through the geographical thinking. Geographical thinking means asking geographical question, gathering geographical data, processing the data with geographical (spatial) methods, and presenting the results in the geographical forms, i.e., maps. All the graduates should be creative and critical and should have the power of scientific challenging and discussions.
- Geography is one independent and overarching discipline and we will offer only one total geography in bachelor level. The master career can be specialized according to the applied objectives of the societies. The doctoral program is also one integrated discipline. The specialty of graduates will be defined according to their dissertation.
- The subjects include the fundamental courses such as physical geography and sustainable development, regional courses such as the human geography of Iran, technical courses such as remote sensing, GIS, and statistics, the applied courses such as evaluating the natural resources, and so for. The students with any high school background should pass all the courses with high quality so that after graduation they have the potential to analyze the human- environment problems and recommend the required solutions.
Key words: geography curriculum, sustainable development, geography of Iran, twenty first century, environmental ethics, geographical thinking, Geography and sustainable development.
Zynab Dolatshahi, Mehry Akbari, Bohloul Alijani, Darioush Yarahmadi, Meysam Toulabi Nejad,
Volume 10, Issue 3 (9-2023)
Volume 10, Issue 3 (9-2023)
Abstract
This study was aimed at examining the types of inversion and their severity using the thermodynamic indices of the atmosphere such as SI, LI, KI and TT at Bandar Abbas Station for 2010-2020. In this study, Radioosvand data at the Bandar Abbas Station was obtained and used from the University of Wioming for the last 11 years (3.5 local) during the last 11 years (2010 to 2020). The results of the analysis showed that the average number of inversion phenomenon in Bandar Abbas was 501 cases per year, as in some days several types of inversion were observed at different altitude. Of these inversion, about 31.6 % are related to radiation temperature inversion, 4.3 % front, and another 64.1 % for subsidence inversion. Due to the air session underneath, the share of subsidence inversions is more than other types of inversion. In the meantime, the most severe inversion of subsidence was 1354 and the weakest inversions were with 29 cases and fronts. In general, the long -term average intensity coefficient of inversion of Bandar Abbas station with a coefficient of 0.062 indicates that the intensity of the city's inversion is mostly extremely severe, which can be very destructive effects both environmentally and physical health in the city's residents. Bandar Abbas follow. The correlation between the inversion elements also showed that by reducing the thickness of the inversion layer, the intensity of temperature inversion also increased.
Sahar Afiati, Bohloul Alijani, Sayyed Mohammad Hosseini,
Volume 11, Issue 1 (5-2024)
Volume 11, Issue 1 (5-2024)
Abstract
Cold and frost are one of the climatic hazards that cause damage to various activities every year. Climate change, on the other hand, causes spatial and temporal changes in glaciation. The purpose of this study is to analyze the temporal-spatial changes and predict the future of glaciers in Hamadan province. CanESM2 model was used to predict the minimum daily temperature in the province. Data mining of general circulation models was Downscaling using LARS-WG model. The above parameters were simulated for a period of 30 years (2050-2021) under three scenarios RCP2.6, RCP4.5 and RCP8.5 for selected stations. The results of the monthly minimum temperature survey in the study stations of the province showed that the minimum temperature in the period (2050-2021) in all studied stations according to all three scenarios will increase in all months of the year compared to the base period. The average minimum temperature of the province is equal to 2.5 degrees Celsius, which in the coming decades based on the scenarios of RCP2.6, RCP4.5 and RCP8.5 will reach 6, 6.2 and 6.3 degrees Celsius, respectively, which is the highest The changes are related to Nojeh station and the lowest is related to Hamedan. The spatial distribution of the beginning and end of freezing in the future period indicates that freezing in the northeastern and northern parts of the province starts earlier and ends later than in other parts of the province, while in the southern parts of the province it starts later and ends earlier. The results of examining the changes in the onset of frost in the next decade compared to the base period showed that in all stations studied the onset of frost will decrease between 3 to 11 days.
Ms Vahideh Sayad, Doctor Bohloul Alijani, Doctor Zahra Hejazizadeh,
Volume 11, Issue 2 (8-2024)
Volume 11, Issue 2 (8-2024)
Abstract
Iran is a country with low rainfall and high-intensity rainfall that is affected by various synoptic systems, the most important of these systems is Sudan low pressure, Therefore, recognizing the low pressures of the Sudan region is of particular importance, The purpose of this study is to gather a complete and comprehensive knowledge of the set of studies conducted about this low pressure, structure and formation and its effects on the surrounding climate. The present study was conducted using the library method and a search for authoritative scientific and research sources in connection with research on low pressure in Sudan and no data processing was performed in it. Thus, it has studied and analyzed the temporal and spatial changes of Sudan's low pressure over several years and its effect on the climate of the surrounding areas, especially Iran. In general, the results of this study can be divided into several categories, including studies on the recognition and study of Sudan low pressure, its structure and formation over time, pressure patterns affecting it at different atmospheric levels, and its effects on the climate of surrounding areas, especially Iran. Has been studied, The effect of this low pressure on seasonal and spring rainfall in Iran, snow and hail, floods, thunderstorms and also the effect of remote connection patterns on this low-pressure system have been studied, and finally, the analysis of these findings has been studied. It can be concluded that the Sudanese low-pressure system is a Low-pressure reverse in the region of Northeast Africa and southwest of the Middle East, which is strengthened and displaced in the upper levels of the Mediterranean and Subtropical jet stream and in the lower surface moisture injection from the Arabian Sea and Oman through high pressure. Saudi Arabia is inwardly the cause of severe instability in Iran and a major cause of heavy rainfall in various parts of the country.
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