NOAA use of Scatterometry Products Presented to CGMS-43 Working Group 2 session, agenda item 10 Author: Paul Chang

Introduction Satellite scatterometry products provide essential information about ocean surface vector winds and sea ice for monitoring and observing for both short and long time scales. These data are provide critical information supporting the analysis, forecasting and warning in the marine environment. Systematic and global coverage requires coordination among satellite agencies to achieve required temporal and spatial sampling.

NOAA routinely uses ASCAT and has started using RapidScat Introduction Satellite scatterometry provides ocean surface vector wind (OSVW) data that is critical in supporting forecasting, warning and analysis of marine weather. Scatterometery data provides important information to aid in the monitoring and characterization of sea ice. Timely and open access to scatterometry data is essential to support the global weather community EUMETSAT (ASCAT), NASA (RapidScat) and ISRO (soon to be launched ScatSat) have committed to open and timely data access Timely and open scatterometer data access from other countries planning or operating missions such as China and Russia would benefit the scatterometer constellation NOAA routinely uses ASCAT and has started using RapidScat Primary user is NWS to support marine weather warning, forecasting and analysis through direct use by the human forecaster (Ocean Prediction Center, National Hurricane Center, and weather forecast offices with marine responsibilities) and through data assimilation for NWP models. The biggest impact of scatterometer OSVW data at NOAA has been through its direct use by the human forecaster. These data are also assimilated into the NOAA global NWP model but modeling centers such as ECMWF, UKMET, JMA and MeteoFrance have demonstrated superior NWP impacts than NOAA has been able to.

Enhanced Resolution ASCAT Products Transitioned to Operational Status ASCAT 25km Wind Vectors (NESDIS) ASCAT 25km Wind Vectors (NESDIS) Enhanced resolution ASCAT products originally developed by Dr.David Long at Brigham Young University have been transition to NOAA’s operational ASCAT processing system. These products have proven very valuable to tropical cyclone forecasting and analysis and for the generation of lake and sea ice products. The example provided is a succession of ASCAT passes over Tropical cyclone Bavi as it passed through the Marianas on March 15, 2015. The bottom set of images show the enhances resolution normalized radar cross-section (NRCS) from ASCAT, where the lighter shades of grey indicate increased roughness which is correlated with higher wind speeds. The center of TC Bavi can be seen as a darker shade of grey which would correspond to the lower wind speeds found in the TC center (less small scale roughness on the oceans surface). ASCAT Enhanced NRCS ASCAT Enhanced NRCS Graphics provided by Roger Edson, NWS-Guam Enhanced resolution products developed by David Long, BYU

RapidScat Ocean Surface Vector Winds NASA/JPL mission launched on September 20, 2014 to the International Space Station Ku-band conically scanning scatterometer similar to QuikSCAT RapidScat surface wind products are produced at 12.5-km and 25-km resolution Products / Applications Marine analysis and forecasting Numerical Weather Prediction http://manati.star.nesdis.noaa.gov Example one day RapidScat coverage – ascending and descending passes NOAA relies on partners to fly satellites where NOAA cannot afford to do so to help meet satellite observational requirements such as ocean surface vector winds. In this case, the NASA research mission RapidScat on the International Space Station is being leveraged for utilization by NWS forecasters. RapidScat displayed in NWS NAWIPS Display System RapidScat reveals HF winds at the northern part from storm center low on November 28th,2014 at its 10:39Z pass. OPC upgraded its 12Z warning to hurricane force (left panel)

Summary Satellite scatterometer data provides critical information that supports both short term weather analysis, forecasting and warning and longer term monitoring and characterization of the environment Proper temporal and spatial sampling require coordination among satellite agencies and a commitment of open and timely data access