Satellite and Ground Based Rainfall Measurement Relationship in Kurdistan Region, Iraq

Remote sensing [RS] of hydrologic processes is becoming increasingly popular tool for frequent, consistent, reliable and cost-effective hydrologic data collection and monitoring. Remote Sensing and space borne measurement systems are in use to observe, detect, and monitor hydrologic parameters such as precipitation, evapotranspiration, soil moisture, and vegetation, etc. However, the satellite-based measurements are prone to errors due to a number of factors related to the atmosphere, environment, sensor sensitivity, and the instrument itself. Remote Sensing data need proper analysis, calibration, and validation before its implementation to real life problems. Amongst other hydrologic measurements, rainfall is also measured by satellites. The Tropical Rainfall Measuring Mission [TRMM] was one of the main satellites deployed for precipitation measurements. Like other Remote Sensing measurements, rainfall measurements are also affected by a variety of factors, which necessitate verifying its validity with some reference measurements. In this study, the TRMM measurements are compared with the ground-based measurements, for six gauging stations in Iraqi Kurdistan Region for years between 2000 and 2016, by using various methods. These include arithmetic differences, Pearson's correlation coefficient R, relative bias and root mean square error [RMSE]. It is found that a strong to medium correlation exist between the point measurements and the corresponding satellite pixel measurements.