Modeling seasonal meteorological droughts in a data scarce arid region under climate change scenarios
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Date
2016
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Universiti Teknologi Malaysia
Abstract
Reliable assessment of the changes in drought characteristics due to climate change is very important for impact assessment and formulation of effective drought preparedness plans. However, availability of reliable climate data is the major obstacle for the characterization of droughts in many parts of the world, particularly in the arid regions located in the developing countries. The major objective of this research is to develop a methodological framework for the modeling of seasonal meteorological droughts in data scarce regions in the context of climate change. Balochistan an arid province of Pakistan, covering an area of 347,190 km2 is considered as the case study for this purpose. Available in situ precipitation records, gauge-based gridded precipitation data and climate change projections of general circulation models (GCMs) are used in the framework. The quality of available in situ monthly precipitation data are assessed and then used for the evaluation of gauge-based gridded precipitation datasets using various robust statistical approaches. The most reliable gridded precipitation dataset is used for downscaling future rainfall projected by seven GCMs of Coupled Model Inter-comparison Project phase 5 (CMIP5) under four Representative Concentration Pathways (RCP) scenarios, namely, RCP2.6, RCP4.5, RCP6.0 and RCP8.5. The historical and future projected rainfall data are finally used to characterize the seasonal droughts using frequency analysis of Standardized Precipitation Index (SPI) estimated for different crop growing periods. The results revealed that the gridded gauge-based precipitation data of Global Precipitation Climatology Centre (GPCC) is more reliable in replicating the observed rainfall of the study area and Support Vector Machine (SVM) is more capable in downscaling historical rainfall. The CMIP5 GCMs projected an increase in precipitation in the range of 13% to 28% in the region by the end of this century. Droughts in a particular season are found to occur more in the region where the amount and the variation of rainfall is more. Therefore, the drought affected area will be changed in the range of -18% to 24% due to the changes in precipitation. The Rabi crop season will be the most effected by droughts in future. The severity-area-frequency curves revealed that for same areal extent the severity of drought will be high for low return periods and low for higher return periods
Description
Thesis (Ph.D (Civil Engineering))
Keywords
Arid regions climate—Research, Droughts—Pakistan—Balochistān, Meteorology—Research