Earth-Sun System Division National Aeronautics and Space Administration SPoRT SAC Nov 21-22, 2005 Regional Modeling using MODIS SST composites Prepared.
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Earth-Sun System DivisionNational Aeronautics and Space Administration
SPoRT SAC Nov 21-22, 2005
Regional Modeling usingMODIS SST composites
Prepared for the Science Advisory CommitteeNovember 21, 2005
Kate LaCasseB. Lapenta, S. Dembek, S. Lazarus, M. Splitt
Earth-Sun System DivisionNational Aeronautics and Space Administration
SPoRT SAC Nov 21-22, 2005
Motivation:Mesoscale features are often observed along SST gradientsCurrent operational models use the coarse resolution (~50 km) RTG SST productBetter 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 USSimulations in the vicinity of Florida from May 2004Hurricane forecasts
All modeling is performed using the Weather Research and Forecasting (WRF) prediction system
Earth-Sun System DivisionNational Aeronautics and Space Administration
SPoRT SAC Nov 21-22, 2005
WRF Operational Forecasts12 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 DivisionNational 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 DivisionNational 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 0021
ADAS ADAS
MODIS SST- RTG SST (K)14 May 2004
Earth-Sun System DivisionNational Aeronautics and Space Administration
SPoRT SAC Nov 21-22, 2005
Computing Capacity: Project Columbia
Earth-Sun System DivisionNational 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: ~50,000Buoys: ~10,000
METARs BuoysMETARs Buoys
Overall there is little difference between 2m temperature forecasts, as expected
Expect to see greater impact of MODIS SSTs locally
Earth-Sun System DivisionNational Aeronautics and Space Administration
SPoRT SAC Nov 21-22, 2005
MODIS - RTG SST (K)14 May 2004
MODISRTG
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 DivisionNational 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
850850
1000
900
950
850
800
SST differences of ~1.5 K have a significant impact on the boundary layer
Earth-Sun System DivisionNational Aeronautics and Space Administration
SPoRT SAC Nov 21-22, 2005
Validation of MODIS forecast01 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 DivisionNational 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 DivisionNational Aeronautics and Space Administration
SPoRT SAC Nov 21-22, 2005
WRF Hurricane ForecastsIn 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, LARadar Reflectivity
42h forecast of3h accumulated precip (in)
Hurricane Katrina06 UTC August 29, 2005
Earth-Sun System DivisionNational Aeronautics and Space Administration
SPoRT SAC Nov 21-22, 2005
Hurricane Katrina Maximum 10m Wind Speed
60
80
100
120
140
160
180
200
12
Z 2
7th
15
Z
18
Z
21
Z
00
Z 2
8th
03
Z
06
Z
09
Z
12
Z
15
Z
18
Z
21
Z
00
Z 2
9th
03
Z
06
Z
09
Z
12
Z
Forecast Date
Sp
eed
(m
ph
)
RTG
MODIS
Observed
Initial cases indicate that WRF hurricane forecasts are sensitive to SSTs.
Earth-Sun System DivisionNational 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
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