In this study is simulation of role of topography in thickness and Inland penetration of sea-breeze in southern coast of the Caspian Sea. The RegCM4 as a regional scale climate model coupled with a lake model and also the reanalysis data of NCEP / NCAR used to determine of the initial conditions of the model. The model was run during the peak of sea breeze on the southern coast of the Caspian Sea (July 2002) in both conditions (with mountains) and (without mountains). the outputs indicated that in without topography condition depth of the sea breeze will increase to the current position the southern slopes of the Alborz Mountains ( latitude ᵒ35 ) but the land breeze in the area is gone. The maximum speed and changes in wind direction observed on the coast southeast and central Alborz respectively. In addition with non-topography conditions, the thickness of sea breeze in different areas significantly has increased with the highest rate on the eastern coast (longitude ᵒ53).

In this research, the relationship between NCPI and CACO indices with autumn precipitation of Southern Coast of Caspian Sea (SCCS) was investigated. In this regard, two sets of data were used (Aphrodite and Station). And the days with more rainfall than long-term average rainfall station and on condition that the rainfall is more than 70% of the region rainfall, were chosen as a day of widespread rainfall. The sea level pressure data was extracted and by cluster analysis and coalition method was clustered. Then, a representative of the widespread precipitation days from station dataset was selected, investigated and analyzed accordingly. The results state that within all patterns there exists a high pressure on the upper side of the Caspian Sea, or a margin of high pressure is extended on to the sea itself. These high pressure regions have relatively cold nature that can cause currents in the northern direction while intersecting with the relatively warm water during the summer. These currents can absorb moisture during their motion towards south which can lead to their instability. In addition, one should not forget the fact that in each three investigated patterns, dynamic factors at high levels have intensified the abovementioned phenomenon and enhanced the instability, which as a result brought about widespread precipitation. Continuously, the abovementioned Remote bond indices were extracted on a daily basis and their relation to north coast widespread rainfalls was studied, which came to a meaningful relationship between these index sets and fall index sets. The relationship is direct with NCPI or surveyed stations, and it’s an inverse relationship with CACO. On the other hand, the study of indexes anomalies on the days without rainfall and with rainfall was done by One Way ANOVA and Tukey test. The result was a meaningful index anomaly on the days with and without rainfall.

In recent years, the severe fluctuations in precipitation have affected various parts of the country. On the southern coasts of the Caspian Sea, precipitation as one of the important climatic parameters has undergone changes due to global climate change. In the present study, we tried to evaluate the effect of climate change on rainfall in this region by applying a suitable model. In this study, observational period rainfall (1961-2001) was analyzed. the output of the HadCM3 model was used. At first, seven synoptic stations were selected and their data were analyzed in terms of accuracy, and length of statistical period, and lost data was restored. The AOGCM data were simulated using the SDSM model and the rainfall values were simulated for the observation period. After confirming the matching of the simulated data with observational data, the values of the Future (2039-2011) is estimated. The estimation errors of the SDSM model were calculated monthly by MBE and MAE criteria, and then compared. The output of the SDSM model was used to study the total annual precipitation in days with rainfall of more than 1 mm in the observation period and the upcoming period (2011-2039) by the R-Climdex model and the values of the PRCPTOT index Became zoning in the Future. The results showed that the model error in season with high rainfall is more than seasons with low rainfall. On a monthly scale, the maximum error occurred in the months of September, October, November and December. The maximum error in the fall and the minimum error was calculated in the spring and April and May months. According to the results, the total annual rainfall in the period of 2039-2011 will decrease in Anzali, Babolsar, Gorgan and Noshahr stations and rainfall will increase in stations of Astara, Ramsar and Rasht. Geographical distribution of selected were 5 sites in the Khuzestan, 20 sites in Bushehr, 24 sites in Hormozghan and 12 sites in Sistan and Baluchistan provinces. In total, 9000 sites were selected with a 2 km2 were suitable for large scale microalgae cultivation. The total area of these sites were estimated to be 18000 km2. The highest number of proper sites were found in Hormozghan province and lowest numbers of sites were found in Khuzestan province. The availability of technical service, carbon dioxide point resources from oil and gas units are an advantages for microalgae related activities in the Bushehr and Khuzestan provinces. The higher quality of water in the Sistan and Baluchistan province is an advantages for development of microalgae biomass production in the area.