Hydrologic regime is highly dependent on climate change, as hydrologic cycle components are directly influenced by climatic conditions. This paper analyzes the impacts of climate change on the hydrologic regime of the Atrak River basin in the northeast of Iran. It drains to the Caspian Sea. The data collected at 11 hydrometeorological stations were examined to detect trends in hydroclimatologic...

hydrologic regime is highly dependent on climate change, as hydrologic cycle components are directly influenced by climatic conditions. this paper analyzes the impacts of climate change on the hydrologic regime of the atrak river basin in the northeast of iran. it drains to the caspian sea. the data collected at 11 hydrometeorological stations were examined to detect trends in hydroclimatologic...

About 50 to 80 percent of precipitation in the southeastern United States returns to the atmosphere by evapotranspiration. As evapotranspiration is a major component in the forest water balances, accurately quantifying it is critical to predicting the effects of forest management and global change on water, sediment, and nutrient yield from forested watersheds. However, direct measurement of fo...

Fresh water supply and its security encounter a high level of fluctuating variability under global climate changes. To address these concerns in catchment water management, a good understanding of land use/cover impacts on the hydrological cycle affecting water supply is crucial. The objective of this study is to define a model to investigate the impact of existing land use/cover on water yield...

The hypothesis of a complementary relationship in regional evapotranspiration allows for estimation of actual evapotranspiration on a regional scale by simple, physically based models that take into account feedbacks in land surface-atmosphere dynamics. A regional, seasonal Advection-Aridity model is used to create a monthly time-series of actual evapotranspiration for a period of 27 years at a...

The original and modified versions of the advection-aridity AA model of regional evapotranspiration are tested with data from the Solar and Meteorological Surface Observation Network SAMSON . The resulting long-term mean annual evapotranspiration estimates are validated against water balances of 25 watersheds that are minimally affected by human activity and contain at least one SAMSON station,...

today, climate change is one of the most important scientific and even the political – social issues. the causes of climate change can be divided into natural and human - made. natural factors have the long-term performance and long history, such as the cycle of solar activity, dusts and gases of volcanic eruptions, geodetic and static agents and etc. human-made factors was mainly formed and ac...

evapotranspiration is one of the most important components of the hydrological cycle which is directly influenced by atmospheric conditions. this study investigated annual and seasonal trends in reference evapotranspiration (et0) and its key influencing climatic variables during 1966-2005 at 10 stations in southern iran (with centrality of fars province). first, multivariate regression analysis...

The components of the surface energy balance were measured for 3 years over a broadleaved deciduous forest using the eddy covariance technique. Within years, the magnitude and distribution of fluxes was controlled by seasonal changes in solar radiation, drought, as well as leaf emergence and senescence. Evapotranspiration increased by a factor greater than five (from about 0.5 to 3 mm day−1) af...

in this study, yield-water and profit function was used to obtain water demand function in agriculture sector. the results showed that the ratio of actual to potential evapotranspiration had positive, significant effecton the ratio of actual to potential yield for wheat and barley. also, square ratio of actual to potential evapotranspiration had negative, significant relationship. after estimat...