Cal/Val of ATMS Snowfall Rate Product for S-NPP and NOAA-20

The ATMS Snowfall Rate (SFR) algorithms for S-NPP and NOAA-20 have been developed with the support of the NOAA JPSS program including its Proving Ground and Risk Reduction (PGRR) program. The S-NPP SFR has reached provisional maturity and has been transitioned to operation in 2018. NOAA-20 SFR is scheduled to be implemented in operation in 2019. The SFR algorithms are based on a 1DVAR approach and retrieve snowfall rate over global land. The focus of this presentation is the calibration and validation of the SFR algorithms. The NCEP Stage IV precipitation analyses were utilized as the snowfall truth data. This dataset takes the Multi-Radar Multi-Sensor (MRMS) precipitation data as input and further incorporates gauge, model, and satellite data, and also applies human quality controls. The calibration against Stage IV significantly improves the SFR product performance. The validation study includes the comparisons of both SFR instantaneous estimates and seasonal averages with the Stage IV data and the results are satisfactory.