1. Earth-Sun System Division National Aeronautics and Space Administration SPoRT SAC Nov 21-22, 2005 Regional Modeling using MODIS SST composites Prepared for the Science Advisory Committee November 21, 2005 Kate LaCasse B. Lapenta, S. Dembek, S. Lazarus, M. Splitt

2. Earth-Sun System Division National Aeronautics and Space Administration SPoRT SAC Nov 21-22, 2005 Motivation:  Mesoscale features are often observed along SST gradients  Current operational models use the coarse resolution (~50 km) RTG SST product  Better specification of the SSTs, especially SST gradients, through the use of a high resolution (1 km) MODIS SST composite, should better resolve the forcing mechanisms which lead to some of the observed features Current Activities:  Operational forecasts over the southeastern US  Simulations in the vicinity of Florida from May 2004  Hurricane forecasts All modeling is performed using the Weather Research and Forecasting (WRF) prediction system

3. Earth-Sun System Division National Aeronautics and Space Administration SPoRT SAC Nov 21-22, 2005 WRF Operational Forecasts  12 km resolution with 37 vertical levels  48h forecasts daily at 00 and 12 UTC  Dynamics and Physics Eulerian mass core Dudhia shortwave radiation RRTM longwave radiation YSU planetary boundary layer Noah land surface model Lin microphysics Kain-Fritsch cumulus  Initialized with 40km NAM analyses  NAM 3h forecasts used for LBCs  SSTs are replaced with MODIS SSTs  Used by both the NWS Huntsville and Mobile offices within AWIPS

4. Earth-Sun System Division National Aeronautics and Space Administration SPoRT SAC Nov 21-22, 2005 NAM WRF Improved Coastal and Marine Forecasts Radar Reflectivity 3h accumulated precipitation (in) 24h forecast ending 00 UTC August 4, 2005

5. Earth-Sun System Division National Aeronautics and Space Administration SPoRT SAC Nov 21-22, 2005 Impact of MODIS SSTs on Mesoscale Weather Methodology:  2 km resolution with 51 levels  Physics differences from operational WRF: No cumulus parameterization WSM 6-class microphysics scheme  24h simulations run daily for May 2004  Parallel runs for both the RTG SSTs and the MODIS SST composites 3h WRF simulation 24h WRF simulation 00 21 ADAS MODIS SST- RTG SST (K) 14 May 2004

6. Earth-Sun System Division National Aeronautics and Space Administration SPoRT SAC Nov 21-22, 2005 Computing Capacity: Project Columbia

7. Earth-Sun System Division National Aeronautics and Space Administration SPoRT SAC Nov 21-22, 2005 Bulk Verification of 2m Temperature Average of 15 days from May 2004 # of observations used METARs: ~50,000 Buoys: ~10,000 METARs Buoys METARsBuoys  Overall there is little difference between 2m temperature forecasts, as expected  Expect to see greater impact of MODIS SSTs locally

8. Earth-Sun System Division National Aeronautics and Space Administration SPoRT SAC Nov 21-22, 2005 MODIS - RTG SST (K) 14 May 2004 MODIS RTG 10m Wind Divergence (s -1 *10 -4 ) 1h forecast valid 01 UTC 14 May 2004 Impact over ocean RTG MODIS Net Sensible Heat Flux (Wm -2 *10) 1h forecast valid 01 UTC 14 May 2004

9. Earth-Sun System Division National Aeronautics and Space Administration SPoRT SAC Nov 21-22, 2005 Horizontal convective rolls Upward Vertical Motion (ms -1 *10 -2 ) RTG MODIS ~100 km 1000 900 950 850 1000 900 950 850 800 Wind Divergence (s -1 *10 -4 ) 1h forecast valid 01 UTC 14 May 2004 RTG MODIS ~100 km 1000 900 950 850 1000 900 950 850 800  SST differences of ~1.5 K have a significant impact on the boundary layer

10. Earth-Sun System Division National Aeronautics and Space Administration SPoRT SAC Nov 21-22, 2005 Validation of MODIS forecast 01 UTC 14 May 2004  Low level convergence from horizontal convective rolls provides forcing for clouds Visible Satellite Image MODIS 10m Wind Divergence (s -1 *10 -4 )  Do the MODIS SSTs also impact precipitation?

11. Earth-Sun System Division National Aeronautics and Space Administration SPoRT SAC Nov 21-22, 2005 Reflectivity (dBZ) 18h forecast valid at 18 UTC 01 May 2004 RTG MODIS Radar composite SST Gradient Convection Along SST Gradient

12. Earth-Sun System Division National Aeronautics and Space Administration SPoRT SAC Nov 21-22, 2005 WRF Hurricane Forecasts  In collaboration with Goddard Space Flight Center, run test cases to determine if WRF forecasts are sensitive to SSTs  Domain configured like May 2004 runs  24 – 48 h forecasts  Initialized with 40 km NAM analyses  NAM 3h forecasts used for LBCs  Parallel forecasts with either RTG SSTs or MODIS SST composite New Orleans, LA Radar Reflectivity 42h forecast of 3h accumulated precip (in) Hurricane Katrina 06 UTC August 29, 2005

13. Earth-Sun System Division National Aeronautics and Space Administration SPoRT SAC Nov 21-22, 2005  Initial cases indicate that WRF hurricane forecasts are sensitive to SSTs.

14. Earth-Sun System Division National Aeronautics and Space Administration SPoRT SAC Nov 21-22, 2005 Summary:  Use of MODIS SST composites is currently ongoing in operational WRF forecasts  May 2004 simulations and hurricane forecasts provide the opportunity to determine the impact of MODIS SSTs on regional forecasts  Preliminary work suggests that the WRF model appears to respond appropriately to high-resolution SST data  Greatest impact of MODIS SSTs is seen in the marine boundary layer