Transcript Application of MODIS SSTs within WRF Science Advisory Committee Meeting 13 June 2007

Application of MODIS SSTs
within WRF
Science Advisory Committee Meeting
13 June 2007
LaCasse, Splitt, Lazarus & Lapenta
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Motivation for using High-Resolution MODIS
SST Fields in NWP Models
 SST known to influence
coastal mesoscale
processes
 Can impact warm-season
SST
precipitation distribution
 Sea breeze circulations
important to heavily
populated areas (HOU, NYC)
 Strong influence on height
of marine boundary layer
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Differences Between RTG and MODIS SSTs
Along the Florida East Coast
RTG_SST
MODIS Composite
MODIS - RTG
Better definition of mesoscale SST gradients
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Experiment Design to Isolate Impacts
Associated with Altering SST
 ARPS Data Analysis System
(ADAS) provides ICs for WRF
• ADAS uses the Bratseth
assimilation scheme
• 20 km RUC used as
background field for ADAS
• Measurements ingested
include surface and upperair
observations and radar radial
winds
• Direct insertion of SST fields
ADAS
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Eulerian mass core
Dudhia shortwave radiation
RRTM longwave radiation
Noah land surface model
YSU planetary boundary layer scheme
Explicit convection
WSM 6-class microphysics scheme
ADAS
3h WRF
simulation
21 UTC
 Weather Research and Forecasting
(WRF) model used for simulations
 3h Eta forecasts used for LBCs
 Dynamics and Physics:
00 UTC
24h WRF simulation
00 UTC
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May 2004 Study Period
Methodology
• 24 h WRF-ARW simulations run
daily for May 2004
SST Difference (MODIS – RTG; K)
14 May 2004
• 2 km resolution; 51 vertical levels
• Parallel runs using either the
½° RTG SST analyses or the 1
km MODIS SST composites
Determine overall impact
• Average similar flow regimes:
o Easterlies (9 - 19 May)
o Westerlies (27 - 31 May)
• Focus on the nighttime hours (5 - 11 UTC)
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Surface Energy Budget
A positive net
sensible heat flux
associated with the
warmer SSTs
Sensible heat flux difference
(MODIS – RTG; Wm-2)
05 to 11 UTC, westerly cases
Increased mixing over
the warmer MODIS
SSTs also led to an
increase in PBL
height over the
Florida Current
PBL height difference
(MODIS – RTG; m)
05 to 11 UTC, westerly cases
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Mesoscale Convergence
Enhanced regions of
convergence were seen when
using the MODIS SSTs
observed
cumulus
While the locations were not
exactly correct, simulations
with the RTG SSTs did not
have these features
convergence zones
Visible GOES image from 1130 UTC 06 May 2004
MODIS WRF 10 m convergence (contours, every 0.5 s-1 * 106)
valid at 1200 UTC (12 h simulation)
MODIS WRF simulations
produced 6% more daily
accumulated precipitation
(27% more along the Florida
Current) when averaged over
May 2004
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Progress since last SAC Meeting
Concluded the May 2004 study period
• Presented preliminary results at the 2006 AMS Annual
Meeting and the June 2006 WRF Users’ Workshop
• Prepared a manuscript for Monthly Weather Review
(revised version submitted May 2007)
Began project with the Miami Weather Forecast Office
(WFO)
• SPoRT has run a parallel version of Miami’s operational
Weather Research and Forecasting (WRF) prediction
system forecasts since mid-February 2007
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transitioning unique NASA data and research technologies to the NWS