Mohammad Darand,
Volume 15, Issue 37 (9-2015)
Abstract
The aim of this study is synoptic analysis of heavy precipitations in Kurdistan Province during 1/1/1961 to 31/12/2010(18263days). By using two thresholds of extensively and intensity of precipitation, 107 days have been recognized. In temporal view, the selected days occurrences in wet seasons of year that start from October to June. By applying the principle component analysis on the sea level pressure during the 107 days, the results showed that 12 components explain about 93 percent of sea level pressure variation. The results of the applying cluster analysis on the component score showed that two circulation patterns result in occurrence of extreme and heavy precipitations in Kurdistan province. In order to recognize heavy precipitation in dry season (June to October), the area mean precipitation for the province have been calculated. According to the 99 percentile threshold and extensively of precipitation the heavy phenomena recognized. By two thresholds 32 days selected and same as to the wet season precipitation the sea level pressure data from NOAA extracted. The data analyzed by Principle Component Analysis and 11 components extracted that explain the 93 percent of variation sea level pressure in the frame study. By doing cluster analysis on the 11 components, one pattern recognized for the sea level pressure. The results showed that in lower atmospheric levels (1000, 925 and 850 hpa) occurred highest convergence on the study region during wet season. The source of humidity in the lower levels is Arabian, Red, Oman, Persian Gulf and Mediterranean Seas. In the high level atmosphere, the value of convergence is low. The sources of humidity in high levels atmosphere are Red and Mediterranean Seas. In the mid level atmosphere (500 hpa) the presence of trough results in nutrition of the instability on the study region. Also during dry season, the highest moisture flux convergence occurred in the low levels but the resource of the moisture is Caspian Sea. In the upper levels (from 700 hpa to up) in addation to Caspian Sea, Mediterranean and Red sea are the resource of heavy precipitations.
Asal Falak, Reza Boran, Farideh Asadian,
Volume 21, Issue 62 (9-2021)
Abstract
This study aimed to investigate the temporal-spatial and synoptic features of thunderstorms in southwest of Iran (Khuzestan, Chaharmahal & Bakhtiari and Kohkiluyeh & Boyerahmad Provinces) It was compiled using volatility indices during the period 1985-2015. Results of Frequency Analysis of Thunderstorms at Dezful Station with 479 cases the highest frequency and Ramhormes with 252 days had the lowest frequency. In terms of seasonal distribution, spring was the most abundant with 39%. On a monthly basis, April had the lowest frequency with 21% and August with only 2 cases. In terms of thunderstorms the highest frequency of thunderstorms with no thunder was 21 percent. Synoptic analysis: Most of the time there is a nave (at level 500) or low pressure in the west of the region, east of the Mediterranean Sea with its tabs clockwise. From the Red Sea and the Persian Gulf, they entered the south, southwest, and west of Iran On the other hand, the high-pressure system on the Gulf of Aden in the east of the region is round in the clock It has injected moisture, especially at a level of 850 millibars. Interaction between the two systems over the course of the day, It has injected moisture from three sources of the Mediterranean Sea, the Red Sea and then the Persian Gulf into the rising systems of the region. The low-pressure counterclockwise movement of the eastern Mediterranean, Along with the high-altitude clock movement over the Gulf of Aden, it has injected moisture at levels of 850 to 700 degrees.
D.r Abas Jahan Abadian, D.r Yaser Kahrazeh, D.r Parviz Reza Mirlotfi,
Volume 25, Issue 76 (3-2025)
Abstract
Factors and stimuli that influence convergence and divergence play a crucial role in determining the process and quality of national cohesion. These factors and stimuli are not synonymous; rather, they are interconnected and mutually influential variables. Understanding the impact of convergence and national cohesion on overall security is of utmost importance. This study aims to investigate and analyze the factors and stimuli that affect national convergence and cohesion in the southeastern region of the country. Similarly, this article seeks to address the fundamental question of the primary factors and stimuli that influence convergence and cohesion among the Baloch people in the southeast. The research findings indicate that various factors significantly impact the convergence and divergence of the Baloch people in the Sistan and Baluchestan province. These factors can be classified into two categories: internal and external stimuli. The study underscores the significance of factors such as mutual trust, decentralization, concentration of industries and decision-making centers, strengthening ethnic identity in alignment with national identity, the role of historical documents in promoting national cohesion, the cultural center of the Baloch people in southeastern Iran, common social customs, and the positive influence of ethnic and national elites. Additionally, the study recognizes the influence of regional political tensions, historical economic ties with neighboring countries, and the prevalence of border markets with Afghanistan and Pakistan as significant factors that shape convergence, divergence, and national cohesion among the Baloch people in the Sistan and Baluchestan province in the southeast of the country.
