daily precipitation data from aphrodite's resources with a spatial resolution of 0.25*0.25 degree for 57 years have been used to detect the trend of precipitation in afghanistan. first of all, monthly, seasonally, and yearly maps and regional mean time series calculated. according to the annual map, mean annual precipitation of the country is about 256 mm. there are two precipitation maxim...

Phrynocephalus przewalskii is one kind of lizards inhabiting inclusively in the desert that has controversial viewpoints on its phylogeny. Based on mitochondrial ND2 gene of 119 samples from 12 geographic populations, we analyzed the effects of environmental factors on the variation of genetic diversity, as well as its relationship to P. versicolor. The results showed that these populations clu...

Precipitation is the main water source for vegetation survival in arid and semi-arid areas. However, previous studies always focus on the effects of precipitation in different time scales, but ignore the effects of precipitation in different spatial scales. To further study the effects of precipitation fluctuation in different spatial scales, we used the wavelet analysis method to analyze its t...

in this paper, the temperature and annual precipitation data has been applied in 44 years for the synoptical stations northwest zone of iran. among the stations, eight of them, which have the perfect data and coverage, has been considered to analysis applied. in this study transfer function models have been used to analysis time series. in this method, firstly, the stations have been modeled th...

Parameters such as future precipitation, temperature, snowfall, and runoff were modeled using PRECIS regionalclimate modeling system in Iran with the horizontal resolutions of 0.44×0.44°C in latitude and longitude under SRESA2 and B2 scenarios. The dataset was based on HadAM3p during the periods of 1961-1990 and 2071-2100. Theoverall precipitation error of the model in the period of 1961-1990 w...

Water is an important resource for plant life. Since climate scenarios for Switzerland predict an average reduction of 20% in summer precipitation until 2070, understanding ecosystem responses to water shortage, e.g. in terms of plant productivity, is of major concern. Thus, we tested the effects of simulated summer drought on three managed grasslands along an altitudinal gradient in Switzerlan...

abstract spi is based on fitting a gamma distribution to precipitation amounts in selected periods. based on current research, the gamma distribution may not be fitted to annual precipitation of some regions. in order to evaluate this subject, annual precipitation have been used during 1958- 2007 at 11 synoptic stations in iran. in first step, values of spi and frequency of different classes of...

prediction of annual average precipitation over a regin is one of important issues in watersherd management and natural resources planning. geostatistics is one of the useful methods for precipitation prediction which varies based on type of the variable. this study was conducted in karoon and dez basins located in southwertern of iran. the data set including 20 years of annual precipitation of...

[1] Controls on interannual variations in water and energy balances of large river basins (10,000 km and greater) are evaluated in the framework of the semiempirical relation E=P 1⁄4 1⁄21þ ðR=PÞ n 1/n in which and E, P, and R are basin mean values of annual evaporation, precipitation, and surface net radiation, respectively, expressed as equivalent evaporative water flux, overbars denote long-t...

The interannual variation of the Bowen ratio, through its effect on the warming extent of available energy to the ecosystem land surface air, heavily influences the ecosystem microclimate and affects the hydrological cycle at both regional and global scales. Although the precipitation amount in southeast China is not expected to change greatly as a result of climate change, the precipitation fr...