Spatial downscaling of IMERG precipitation estimates using statistical techniques

The aim of this study was to spatially downscale the Precipitation Estimates (PEs) from the Global Precipitation Measurement (GPM) mission, using the Integrated Multi-satellite Retrievals for GPM (IMERG), over a complex region in Greece. For this purpose, the Multivariate Linear Regression (MLR) and the Residual Correction (RC) techniques were utilized, in conjunction with remote sensing cloud properties from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument, onboard Aqua satellite, namely Cloud Optical Thickness (COT), Cloud Effective Radius (CER) and Cloud Water Path (CWP). The downscaled PEs were then validated using regional rain gauges’ measurements. According to our analysis, the 0.01^o downscaled IMERG PEs were found to be more accurate than the original 0.1^o IMERG data, over the region. In addition, the implementation of the RC technique to the 0.01^o downscaled PEs was observed to improve the performance of the MLR downscaling method. This research was funded by the EU project titled: WATERLINE project id CHIST-ERA-19-CES-006.