Amin Hassani; Masoud Tajrishy; Ahmad Abrishamchi
Abstract
Knowing the rate of evaporation from surface water resources such as channels, reservoirs and lakes is essential for precise management of water balance. In this study, monthly evaporation was determined by Bowen Ratio Energy Budget (BREB) method for Alghadir Lake (Saveh, Iran) from 1995-2007. Some variations ...
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Knowing the rate of evaporation from surface water resources such as channels, reservoirs and lakes is essential for precise management of water balance. In this study, monthly evaporation was determined by Bowen Ratio Energy Budget (BREB) method for Alghadir Lake (Saveh, Iran) from 1995-2007. Some variations have been observed on the estimated evaporation of the energy budget at different years, ranging from 151 cm for 1997 to 174 cm for 2005. Also, there is no specific monthly evaporation pattern for all the years, but evaporation rates were low in Jan and Feb and highest during the Jul and Aug. Surveying of lake thermal structure showed that inflow and outflow energy fluxes to this water volume have large variations and incoming solar shortwave radiation, incoming atmospheric longwave radiation and longwave atmospheric radiation emitted from the water surface are largest energy fluxes for this small and deep lake.
Peyman Daneshkar Arasteh; Masoud Tajrishy; Bahram Saghafian
Abstract
Earth skin temperature including soil, water, snow, and vegetation surface temperatureis one of the main variables in geo-science studies. Generally, spatial distribution ofsurface temperature is needed in such studies. Spatial monitoring of surface temperatureis possible using remote sensing data, and ...
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Earth skin temperature including soil, water, snow, and vegetation surface temperatureis one of the main variables in geo-science studies. Generally, spatial distribution ofsurface temperature is needed in such studies. Spatial monitoring of surface temperatureis possible using remote sensing data, and the time series of images provide acontinuous spatio-temporal framework required in modeling energy balance of regionalevaporation, optimization of energy demands or dispersion of atmospheric pollutions. Inthis paper, some common methods of surface temperature estimation using satelliteimagery were introduced and calibrations of several forms of split window equationwere addressed for Sistan area, Iran. Split window method is based on the fact that theatmospheric transmittance varies with wave length and uses a combination of thermalinfra-red brightness temperature and emissivity. To calibrate the split window equation,ground observations and 22 NOAA/AVHRR images during 1992 to 2002 were used todevelop regression models. Statistical tests were performed to evaluate the equationsand coefficients. Ten AVHRR images were used to verify the developed equations. Theresults indicated that three different forms of split window equations successfullypassed the χ2 statistical test. Both, F and Kruskal-Wallis tests showed that they are notstatistically different at 95 percent significant level. Therefore, the simplest form ofequation was used to derive surface temperature maps in the Sistan region, and isrecommended as the most applicable one.
