Intercomparison of integrated water vapor production retrievals from HY-2 and AMSR2

As the one of primary parameters retrieved from HY-2 RM, the there years long from Jan 2013 to Dec 2015 global integrated water vapor (WV) obtained from HY-2 scanning microwave radiometer were preliminarily validated using other operational space-borne radiometer observations. The gridded water vapor productions of AMSR2 were seen as “true data” in this inter-comparison. For the global scale, the bias and RMS difference of the dataset of these space-borne collocated WV observations was respectively 0.12 mm and 1.89 mm during this three years. With analysis of global map of mean difference of the collocation between HY-2 RM and AMSR2, the map of bias distribution appeared that there were a positive deviation about 0.2∼0.3mm in the tropic ocean where the precipitation and humidity were in relative high level, a negative deviation in the coastal and near-shore regions. The results suggested that accuracy of retrieval algorithm for HY-2 WV productions obviously depends on latitude. There were potential and room for improvement of retrieval accuracy of WV, for correcting overestimation of WV in the tropic sea and underestimation in the inshore regions relative to AMSR2 observations.