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

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

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

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

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 ADAS MODIS SST- RTG SST (K) 14 May 2004

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

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

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

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 Wind Divergence (s -1 *10 -4 ) 1h forecast valid 01 UTC 14 May 2004 RTG MODIS ~100 km  SST differences of ~1.5 K have a significant impact on the boundary layer

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?

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

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

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.

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