IIIT Hyderabad Publications |
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A Comparative Analysis of Regional Drought Characterization over Krishna River Basin in India Using Potential and Actual EvapotranspirationAuthors: SIREESHA NAIDU GALLA Conference: Asia Oceania Geosciences Sciences Date: 2018-06-06 Report no: IIIT/TR/2018/34 AbstractAmong the extreme events, droughts are the most widespread and slowly developing hydro meteorological events remain for a long duration affecting natural resources, environment and the people. Few studies included reference evapotranspiration to account for climatic water availability in drought characterization such as Standardized Precipitation–Evapotranspiration Index (SPEI). However, a drought prediction model should consider the actual evapotranspiration to include the physical water availability and land surface changes of a region. The Budyko curve is used to estimate the actual evapotranspiration as a function of the aridity index. The drought index is based on the probability distribution of the difference between precipitation and Actual Evapotranspiration (AET), which represents the measure of the water surplus or deficit for a particular month. The gridded daily precipitation data from India Meteorological Department (IMD) available for the period of 1901 to 2015 at 0.25o X 0.25o resolution and the gridded daily average temperature at a resolution of 1o X 1o resolution was used in the study as temperature observational data sets. The regional drought prediction model developed in the study is applied on Krishna River basin in India. The monthly PET was estimated with the Thornthwaite equation using mean temperatures over the entire Krishna river basin. The AET is estimated at 12 month scale using Budyko equation, which combines the precipitation, AET and PET estimated from Thornthwaite equation. The performance of drought index is evaluated using historical droughts and projected variability under climate change. The results of the study reveal that inclusion of AET in the drought characterization along with PET and precipitation into account can drive the areas into moderate drought that would experience extreme drought under if only PET is considered. Full paper: pdf Centre for Spatial Informatics |
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