The Evaluation of Satellite-Based Rainfall Estimates Comparison with Ground Rain Gauge Data for Selected Areas Over the Lower Indus Basin of Pakistan.

Abstract

Pakistan’s rainfall patterns are altered due to climate change, rainfall showers are for fewer periods with high intensity which results in successive floods and drought. Rainfall estimation is vital in non-farm water utilization and water resources management. Conventional methods for rainfall measurement are used in Pakistan i.e. ground rain gauge station, this method has several limitations as they are difficult to install and operate at high evaluation, the method requires continuation record-keeping, has chances of error due to human intervention, covers less area and floods affected them badly, etc. Satellite-based rainfall estimates are a better alternative to estimating rainfall depths with high accuracy. In this study, satellite rainfall estimates are geared from NASA satellite product Global Precipitation Mission (GPM) and rain gauge data for the study area for the period of twelve years from 2005 to 2017 collected from Pakistan Water and Power Development Authority (WAPDA) for eight numbers ground rain gauge stations. The collected rainfall data were evaluated using statistical tools. The scattered diagram was developed for each station using linear regression analysis. A regression line is a tool for checking the effect of the independent variable on the dependent variable. The coefficient of determination (R2) lies between 0.7513 to 0.8625, indicating a significant result of 75.13% to 86.25%. GPM is an alternative for timely rainfall estimation, especially for remote areas with high elevations. It has the potential to overcome scarcely rain-gauged catchments for hydrological modeling, used for irrigation scheduling. Its role can also be vital in calculating the climate change impact on rainfall patterns.