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 gau...

spatial distribution of thermal regions is dependent on local factors and circulation patterns in long terms. recognition of spatial distribution of temperature in geographical regions could be help on planning and environmental policies. the aim of this paper is recognition and detachment of thermal regions in iran. for this object, maximum daily temperature data have been provided using 620 s...

Eight years of Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) data show how convective systems of different types contribute to precipitation of the South Asian monsoon. The main factor determining the amount of precipitation coming from a specific system is its horizontal size. Convective intensity and/or number of embedded convective cells further enhance its precipitatio...

springs are the important water resources, which thier study is necessary in terms of their management and exploitation. in northern iran, the karst springs locate in the central alborz highlands and alluvial springs on the caspian southern coasts.the karst and alluvial springs discharge is variable because of different conditions in terms of aquifer, topography and precipitation .this study ha...

Coastal vegetation comprises a number of coastal specialists and terrestrial generalists. It remains unclear how they persist on disturbed and undisturbed coastal conditions. We tested the hypothesis that coastal specialists may be superior to terrestrial generalists on supratidal zones of coasts, but their superiority can be influenced by human disturbances. Eight separate sandy coasts of the ...

the purpose of this research is to analyze heat waves characteristics in the warm period of the year as a climatic hazard in iran. in this study, the daily maximum temperature is taken at 44 synoptic stations during the period 1981-2010. these temperature values were used to extract the intensity, frequency and duration of heat waves using percentile thresholds of 90, 95, and 98. the results sh...

â â â  this paper attempts to investigate the relationship between 500hpa circulation patterns and weather types (coldest, warmest and raining) over 16 synoptic stations of mountainous region of iran. the mountainous region of iran covers about 670000 square kilometer (41 percent) of iran. in this paper have been investigated the relationship between circulation patterns in 500hpa level with we...

The purpose of this research is to analyze heat waves characteristics in the warm period of the year as a climatic hazard in Iran. In this study, the daily maximum temperature is taken at 44 synoptic stations during the period 1981-2010. These temperature values were used to extract the intensity, frequency and duration of heat waves using percentile thresholds of 90, 95, and 98. The results sh...

In this study, the relationship between annual sunspot number (ASN) and annual precipitation totals (APT) has been investigated over the northern coasts of the Persian Gulf and Oman Sea by using two statistical methods: contingency tables and cross-correlation function. Only Bushehr and Jask stations (270 mm and 140 mm mean APT) have long term monthly precipitation records started instrumentall...

A scientific definition of the type of mountain area and an exploration of the spatial correlation between different types of mountain areas and regional land use at the county level are important for reasonable land resource utilization and regional sustainable development. Here, a geographic information system was used to analyze digital elevation model data and to define the extent of mounta...