EVALUATION OF STATISTICAL MODEL FOR FUTURE PRECIPITATION AND TEMPERATURE IN DRAINAGE AREA OF JHELUM RIVER, PAKISTAN

This study aims to the evaluation of an extensively used decision support tool "Statistical Down Scaling Model" (SDSM) for assessment of future variation in Precipitation (PPT), Temperature maximum (Tmax) and Temperature minimum (Tmin) of Jhelum River's Drainage Area (JRDA), Pakistan. The current framework considered the partial correlation percentage (PRP) within 46.50%, 46.06%, 35.96%, and 21.97% to evaluate the effective predictors or the predictands. The R-2 values for both SDSM-M and SDSM-A models were calculated in scenarios 2.6, 4.5, and 8.5 RCPs under CIMP5 (CanESM-2). The R-2 precipitation values under all scenarios ranged between 82%-88% in SDSM-M. Whereas, R-2 for Tmin and Tmax was between 69%-71% and 68%-74%, respectively. For the SDSM-A model, precipitation ranged between 76.5%-80% for all scenarios, while Tmin and Tmax were found to be lying between 85%-92% and 89%-96%, respectively. Both models reflected seasonal and annual projected precipitation under RCPs 2.6, 4.5, and 8.5 from 13%-68%, 25%-69%, and 13%-71% in the 2020s-2080s, respectively. Tmin in annual models under RCP 2.6 decreased from -0.91 degrees C to -1.89 degrees C, -0.20 degrees C to -1.46 degrees C and -0.87 degrees C to -1.90 degrees C.The temperature under RCPs 2.6, 4.5, and 8.5 expressed a rise during the period 2020s-2080s from 0.04 degrees C to 3.75 degrees C, 1.02 degrees C to 2.62 degrees C, and 1.03 degrees C to 2.60 degrees C for the monthly model. Furthermore, an increasing trend was observed for Tmax from 0.01 degrees C to 4.18 degrees C, 0.01 degrees C to 4.49 degrees C and 0.12 degrees C to 3.90 degrees C in the period 2020s-2080s under RCPs 2.6, 4.5, and 8.5. The results revealed that the region will be generally warmer and wetter compared to the historical record. SDSM-A exhibited normal variation for the observed data compared to SDSM-M. It was concluded that the SDSM-A provided good results for average seasonal and annual temperatures (Tmax and Tmin). The results predicted the occurrence of more extreme events in JRDA during the 21st century. This study will be useful for water resources under different climatic conditions.