GPM Products From the Microwave-Integrated Retrieval System

An updated version of the microwave-integrated retrieval system (MiRS) V11.2 was recently released. In addition to the previous capability to process multiple satellites/sensors, the new version has been extended to process global precipitation measurement (GPM) microwave imager (GMI) measurements. The main purpose of this study is to introduce MiRS GPM products and to evaluate rain rate, total precipitable water (TPW), and snow water equivalent (SWE) using various independent datasets. Rain rate evaluations were performed for January, April, July, and October 2015 which represents one full month in each season. TPW was evaluated on four days: 9 January, 1 April, 13 July, and 1 October, which represents one full day in each season. SWE was evaluated for a week in January 2015. Results show that MiRS performance is generally satisfactory in regards to both global/regional geographical distribution and quantified statistical/categorical scores. Histograms show that MiRS GPM rain rate estimates have the capability to reproduce moderate to heavy rain frequency distribution over land, and light rain distribution over ocean when compared with a ground-based reference. Evaluations of TPW show the best performance over ocean with the correlation coefficient, bias, and standard deviation of 0.99, <;1.25 mm, and <;2.4 mm, respectively. Robust statistical results were also obtained for SWE, with a correlation coefficient, bias, and standard deviation of 0.77, 1.72 cm, and 3.61 cm, respectively. The examples shown demonstrate that MiRS, now extended to GPM/GMI, is capable of producing realistic retrieval products that can be used in broad applications including extreme weather events monitoring, depiction of global rainfall distribution, and water vapor patterns, as well as snow cover monitoring.