Transition and Assessment of GPM Rain Rate Products to Operations

Acquiring useful precipitation observations can be challenging for forecasters given that precipitation is highly spatially variable and conditions change very rapidly.  For locations with limited radar coverage, forecasters depend on gauge networks, satellite observations, and model forecasts.  In 2014, NASA launched the Global Precipitation Mission (GPM) ‘core’ satellite with a passive microwave imager (GMI) aboard, providing a new set of rain rate data from a sun-synchronous orbiter.  In addition to the GMI’s rain rates, several other legacy passive microwave instruments are now intercalibrated to the GMI to produce a robust dataset of observations that can feasibly be used in near-real time.  Since 2015 NASA-SPoRT has been transitioning these research datasets to operations experimentally with specific National Weather Service Forecast Offices in data-void regions to assess the operational utility of GPM.

Working with selected NWS forecast offices, several demonstrations of this experimental/operational capability have been conducted by NASA-SPoRT.  We evaluated its utility and identified strengths and limitations of this algorithm in operations, notably in data-void regions like Alaska.  Training modules were developed by SPoRT with support from the GPM science team to address the interpretation of GPM rain rate products compared to gauge data, models, and other precipitation data sources.  Furthermore, we sought to understand how the assessment and qualitative validation information can improve the GPM dataset and underlying algorithms to assist operations for flood forecasting.  Herein we will discuss the transition, training, and operational value of this research dataset in NWS forecast operations with specific emphasis on the Alaska Region.