This survey was carried out by R/V Guilan ship with a conical plankton net of 100 micron mesh by vertical hauls at different stations and depths of 5, 10, 20, 50 and 100m in 2010. In this study, 16 species formed the zooplankton community including 4 species of Copepoda, 4 species of Rotatoria, 2 species of Protozoa and 4 species of Cladocera from Holoplanktons and 2 species of Balanus sp and Lamellibranchiata larvae from Meroplanktons. The annual results revealed that the mean abundance of zooplankton were 5477±5815 ind/m3 in spring but the maximum biomass (64.58±124.61mg/m3) was in winter that was affected by Rotatoria. The maximum mean abundance and biomass of Copepoda were in summer that were 2830±2342 ind/m3 and 22.52±21.78 mg/m3, respectively and the abundance decreased gradually since autumn and reached the least in winter but increased since spring. The mean maximum abundance of Cladocera (115±142 ind/m3) was in spring but it gradually decreased, The Protozoa constituted the least community and biomass of zooplankton in SOUTHERN area of CASPIAN SEA. The zooplankton community also was affected by Meroplanktons including Cirripedia and Lamellibranchiata Larvae in spring and the Rotatoria contributed highly in zooplankton community in winter with the mean abundance and biomass of 2604±5876 ind/m3 and 50.71±115.33 mg/m3 respectively. It was observed the reduction trend in abundance from surface depths to deeper depths in whole of the year. There were 75% of zooplankton community in stations with 5 to 20m depth and 25% of community in stations with 50 to 100m depth in spring, and also 74% in stations with 5 to 20m depth and 26% in stations with 50 to 100m depth in summer, 73% in stations with 5 to 20m depth and 27% in stations with 50 to 100m depth in autumn and 85% in stations with 5 to 20m depth and 15% in stations with 50 to 100m depth in winter. In analysis of different area of SOUTHERN basin of CASPIAN SEA the maximum abundance was observed in west in spring, summer and winter which were 7514±8115 ind/m3, 3909±2609 ind/m3 and 8129±11587 ind/m3, respectively. There was 2283±2134 ind/m3 in center area in autumn. The annual statistical analysis revealed that, there was significant difference in total zooplankton community between sampling stations, depths and layers in whole of the year.

The presence of water resources, particularly rivers, significantly influences site selection. Throughout history, settling near rivers has brought numerous advantages, but it has also posed certain risks. This study focuses on the sub-basins southeast of the CASPIAN SEA. Initially, we explore the connection between the layout of ancient settlements and the drainage networks. Additionally, we analyze the relationship between flood risk and the settlement patterns of these ancient sites by estimating the flooding risk based on linear, areal, and relief aspects. This reSEArch marks the first time such an analysis has been conducted. The findings underscore the importance of proximity to rivers in site selection, with areas close to rivers with lower stream orders being the most favorable for settlements. The study reveals a decrease in the frequency of sites near higher stream orders in relation to flooding risk. Conversely, there is an increase in the frequency and density of ancient sites near the first stream orders and at greater distances from the rivers, coinciding with an elevated flooding risk in the sub-basins. These results indicate that the inhabitants of the southeastern areas of the CASPIAN SEA sub-basins were cognizant of the flooding danger and factored it into their decision-making when selecting settlement sites

To identify temporal and spatial precipitation models in the SOUTHERN COASTS of CASPIAN SEA, principle component analysis (PCA) and clustering analysis (CA) were used. In this study, using daily precipitation data, measure of central tendency, statistical dispersion and percentages of three variables of duration, amount and intensity of precipitation events in 46 synoptic, climatic and rain gauge stations from 1957 to 2004 were calculated. SOUTHERN COASTS of CASPIAN SEA were regionalized on the basis of standardized data of the 3 variables and its regimes were calculated. Precipitation events of each station was divided into four groups including light, moderate, heavy and super heavy and its regimes were explained. The results showed that there are six monotonous precipitation regions in this area as the spatial variations are more in central parts than east and west parts. The mean of rain duration, variance of precipitation duration and precipitation amount as well as skewness and kurtosis of precipitation amount and intensity are more in central and western parts than eastern and mountainous areas. Despite the fact that precipitation mean is maximum from September to December in different regions but its frequency is different. Frequency regimes analysis showed that coastal areas (regions of 1, 2 and 3), mountainous area in west of Guilan Province (part of region of 3) has maximum frequency from September to December. The mountainous areas in center of Mazandaran province (region of 4) as well as the other regions in mountainous areas (region of 5) have the highest frequency of precipitation events from April to August and in winter respectively. Also, the results show that July and summer have minimum frequency of events in all precipitation groups. The light, moderate and heavy precipitation events have maximum frequency events in March and winter as well as the super heavy precipitation events has the highest frequency in October and autumn.

The aim of this paper was to study the time detection for the arrival and initiation of Siberian high pressure activities in SOUTHERN coast of the CASPIAN SEA. Therefore, the temperature and pressure data were collected from Anzali, Babolsar and Gorgan stations for the September, October, November and December months during the statistical periods of 1971 to 1980. The criteria for Siberian high pressure current were the presence of the ridge system with the isobar line of minimum 1020hp. in SOUTHERN COASTS of CASPIAN SEA, along with the establishment of a Siberian high pressure core cell in the eastern longitude of 60° to 120° and northern latitude of 40° to 60° in the region. Whenever the changes in temperature and pressure of stations occurred simultaneously by a penetration of Siberian high pressure ridge on the region, the time had been registered as the arrival time of Siberian high pressure to the SOUTHERN COASTS of CASPIAN SEA. Accordingly, the second decade of October (third decade of Mehr) was recognized as the initiative stage of Siberian high pressure activities in the region with the highest frequency of 50% during the statistical period.      

With due attention to importance of climate change and natural ecosystem sensibility of the study area, in this reSEArch have been studied the probable climatic departure from normal and the existence of trend in climatic time series is detected by statistical tests. The first on the basis of rank- method Mann Kendal, it is tried to identify of changes and then recognize their type and time. The results which are provided of data analysis by this method show that the most changes started as abrupt and it is known that these changes belonged to both type of trend and oscillation. The minimum temperature shows a positive trend and the maximum temperature shows a negative trend in the most of selected stations. Therefore, it seems the range of temperature has reduced during the study period. Also, the percentage of changes on winter and summer has been more than spring and autumn situation. Eventually, there aren't any coincident between the selected stations for purposes of changes beginning.

Many people know the important effects of CASPIAN SEA winds and storms on the economy of three provinces of Iran including Gilan, Mazandaran, and Golestan that they form one exclusive and extent area which have moderate and humid climate. This paper used a synoptic climatologically approach, which combine a number of atmospheric factors. Using daily and monthly winds data including their speed and direction for determining of 61 wind waves (1983 to 1985), and then 20 representative ones and analyzing daily air maps, 13 synoptic patterns of troughs, and polar front jet stream (PFJ) at 500 hPa level, and Siberian High is produced during the peak days of wind waves and middle days of calm periods. Results indicate that much of troughs grouped in the west of CASPIAN SEA during the peak days of wind waves but they were completely scattered during the middle days of calm periods. Also, the northwest-southeast direction of trough axes and FPJ location between 40 to 50°E confirmed that troughs have dominant effect for the appearing of sever winds. Finally, the schematic and tridimentional pattern of SOUTHERN CASPIAN SEA winds as another result showed during autumn, dominant wind speed is lower than winter. This can be the principal factor of maximum rainfall during autumn in study area.

The present study was performed with the aim of investigation in phenotypic variations of Cyprinus carpio as an economically worth species in south basin of the CASPIAN SEA. In winter of 2015, totally 74 specimens were collected from Anzali, Miankaleh and Gomishan and the morphometric information were extracted. The obtained results of ANOVA were indicated a high rate of phenotypic variations (23 out of 25). PCA detected HH1 (head height character) as the most important feature in making variations among populations. Cluster Analysis classified all samples in three major clades. So it can be concluded that there is at least three separate stocks of common carp in the SOUTHERN basin of the CASPIAN SEA which it is high recommended that should be considered in stocks management in order to prevent subsequent problems including inbreeding and reduction in genetic fitness.

Climate change has direct and indirect consequences on crop production and food security. Agriculture and crop production is one of the factors which depend on the weather conditions and it provides the human requirements in many aspects. The objective of this study is to assess the impacts of future climatic change on irrigated rice yield using the CERES-Rice model in the SOUTHERN Coast of CASPIAN SEA under three climate change scenarios of Sra1b, Sra2 and Srb1. Required data for this reSEArch includes the meteorological, soil and crop management data. The meteorological data include the daily data of minimum temperature, maximum temperature, solar radiation and precipitation during 1981-2010 and Global Climate Models (HADCM3, ECHAM5, IPCM4, GFCM2, NCCCSM and INCM3) during 1971-2000. Soil and product management data provided fromfield experiment was conducted from 2008 to 2009at the Rice ReSEArch Institute in Rasht. Validating of Global Climate Models show that ECHAM5 climate model has the highest correlation with the lowest error to simulate the future temperature and precipitation.We used ECHAM5 climate model coupled with a crop growth model for simulating of the effects of climate change on rice protection. The results of prediction of climate change scenarios show that minimum and maximum temperature will be ascending and precipitation will be decreasing in the Rasht station. Results of simulated yield and biomass of the rice crop base on scenarios of Sra1b, Sra2 and Srb1 show that rice crop yield and biomass decrease with increasing of mean temperature and decreasing of precipitation.

The main feature of the Earth system is climate changes altering climatic elements such as precipitation and temperature, in short and long-term periods. Drought is one of the climate changes affecting on several arid, semi-arid and even wet regions of the world with different intensities. The main goal of this study is investigation on the synoptic effective mechanisms in order to identify the monthly dry periods in the SOUTHERN COASTS of CASPIAN SEA as well as presenting its patterns. First of all, in order to recognize the patterns affecting on the drought of this area, 30-year statistical data (1977-2006) extracted and then, the wet and dry months were identified using the standard score index (Z). Afterwards, the synoptic maps were provided using the Grads software based on geopotential data and the pressures of the SEA levels, 850, 700, 500 hpa. Moreover, these maps were used to extract the relative pattern. Statistical processing of precipitation and temperature data illustrates that in most of the wet months, standard precipitation index (z) and temperature Z are positive and negative, respectively. Due to high rainfall, temperature is lower than normal and its reverse is observed in dry months. It means that the low rainfall coincides with the negative precipitation and positive temperature indexes. Synoptic maps show that Siberian high pressure and blocking system over Eastern Europe (located on the Ural Mountains) have the most influence on the SOUTHERN COASTS of CASPIAN SEA, Therefore, by means of creation of the blocking systems and their spatial displacement are originated the wet and dry periods in the area.