1. The National Hurricane Center and Geostationary Sounders: Needs and Issues NATIONAL HURRICANE CENTER Jack Beven WHERE AMERICA’S CLIMATE AND WEATHER SERVICES BEGIN November 4, 2009

2. NHC Sounder Issues The NHC does not directly use satellite sounding data as part of the operational data stream.The NHC does not directly use satellite sounding data as part of the operational data stream. Microwave sounding data is used for tropical cyclone intensity estimates.Microwave sounding data is used for tropical cyclone intensity estimates. Satellite sounder data primarily contributes to NHC operations through improvement in numerical weather prediction models.Satellite sounder data primarily contributes to NHC operations through improvement in numerical weather prediction models. NHC Area of Responsibility

3. Temporal Resolution Issues Low-earth-orbiting sounders at best provide data over an area of interest once every few hours.Low-earth-orbiting sounders at best provide data over an area of interest once every few hours. Moving meteorological features such as TC can slip through the swath gaps in LEO sounder coverage.Moving meteorological features such as TC can slip through the swath gaps in LEO sounder coverage. GEO sounder would produce higher temporal resolution data and cover the swath gaps.GEO sounder would produce higher temporal resolution data and cover the swath gaps.

4. Tropical Cyclone Intensity Estimates DeMaria (GUC4) showed that IR soundings could be used to enhance AMSU-based TC intensity estimates.DeMaria (GUC4) showed that IR soundings could be used to enhance AMSU-based TC intensity estimates. IR eye soundings could be used for intensity estimates at times when microwave soundings are not available.IR eye soundings could be used for intensity estimates at times when microwave soundings are not available. Cloud issues would likely limit these estimates to TCs with well-developed eyes.Cloud issues would likely limit these estimates to TCs with well-developed eyes. 929hPa AMSU depiction of TC warm core Hurricane Inez (1964)

5. Total Precipitable Water Products GOES-R sounder data could temporally enhance the microwave-based TPW product over the oceans, making it easier for the NHC to detect and track important moist and dry features.

6. Potential Geostationary Sounder Input High quality GEO sounder data could have major impacts on numerical weather prediction models and resulting TC forecasts, resulting in significant socio- economic benefits. Almost $2 B of economic benefits over the lifetime of a satellite series could be realized beyond the current GOES system due to high spectral resolution enhanced sounder data (Bard et al., GUC5).High quality GEO sounder data could have major impacts on numerical weather prediction models and resulting TC forecasts, resulting in significant socio- economic benefits. Almost $2 B of economic benefits over the lifetime of a satellite series could be realized beyond the current GOES system due to high spectral resolution enhanced sounder data (Bard et al., GUC5).

7. Best case scenario: A hyperspectral IR sounder with a partner MW sounder! GEOSTAR – proposed microwave imager/ sounder in geostationary orbit (PATH mission in the Decadal Study)GEOSTAR – proposed microwave imager/ sounder in geostationary orbit (PATH mission in the Decadal Study) Geostationary microwave sounder could allow high- frequency, high spatial area coverage for NHC’s microwave data needsGeostationary microwave sounder could allow high- frequency, high spatial area coverage for NHC’s microwave data needs

8. Summary The NHC could significantly benefit from a sounder on the GOES-R satellite seriesThe NHC could significantly benefit from a sounder on the GOES-R satellite series The greatest benefit of input from an IR sounder data might be from assimilation into NWP models that forecast TC track and intensityThe greatest benefit of input from an IR sounder data might be from assimilation into NWP models that forecast TC track and intensity Sounder data could also be used in TC- specific products such as sounder-based intensity estimates, and in other derived products such as TPWSounder data could also be used in TC- specific products such as sounder-based intensity estimates, and in other derived products such as TPW