Status Report for WRF’s Variational Data Assimilation System (WRF-Var)Infrared Satellite Data
Assimilation at NCAR
Hans Huang, Syed Rizvi, Hui Shao, Meral Demirtas, Xin Zhang
National Center for Atmospheric Research
Work supported by AFWA, NASA, NSF, KMA
01/30/2009 JCSDA - Infrared Sounding Working Group (ISWG) *
Introduction to satellite data assimilation at NCAR
Practical issues with AIRS data assimilation
Current developments on infrared radiances
Outline
WRF-ARW: Local Area Model (with global version) + TL/ADJ version
DART: Ensemble Data Assimilation (EnKF, ETKF, …) (no radiance yet)
WRF-Var: Variational Data Assimilation (3DVar, FGAT, 4DVar) + Hybrid system
Community support
01/30/2009 JCSDA - Infrared Sounding Working Group (ISWG) *
Satellite DA: WRF-Var capabilities
Retrievals (T / Q profiles)
GPS Radio Occultation
Active sensors: Quikscat
AMSU-A from NOAA15, 16, 18, EOS-Aqua, METOP-2
AMSU-B from NOAA15, 16, 17
MHS from NOAA18, METOP-2
Satellite DA: WRF-Var capabilities
Retrievals (T / Q profiles)
SATEM (from AMSU)
AIRS retrievals (NASA version 5): NASA-EOS Project to assess impact over Antarctica
GPS Radio Occultation
Active sensors: Quikscat
AMSU-A from NOAA15, 16, 18, EOS-Aqua, METOP-2
AMSU-B from NOAA15, 16, 17
MHS from NOAA18, METOP-2
AIRS from EOS-Aqua: AFWA Project to incorporate in operational 3DVar
SSMIS from DMSP16
T
Surface
O3
T
Q
RTTOV
CRTM
(REL-1.1)
NCEP (and most ECMWF) observation errors statistics consistent with innovations
Error factor tuning from objective method (Desrozier and Ivanov, 2001)
NCEP
ECMWF
Channel number`
Pixel-level QC
Cloud/Precipitation detection (NESDIS)
Thinning
Modeling of errors in satellite radiances:
Bias Correction: Static and Variational
“Offline” bias correction
“Variational” bias correction
After BC
Before BC
VarBC: Issues with regional models
VarBC Timeseries
poor knowledge of gas concentrations (CO2, …)
errors in definition of ISRF
errors in mean absorption coefficient
Timeseries of estimations
Gamma sensitivity
From « hole hunting »
(identifying clear pixels)…
/
= Radiance calculated for
RTM
Cloud Top Pressure (hPa)
AIRS Cloud Detection
01/30/2009 JCSDA - Infrared Sounding Working Group (ISWG) *
Current Developments: Cloudy Radiances
Current Developments: Observation Impact
AIRS/AMSU (v.5) Retrievals over Antarctica
Collocate with COSMIC retrievals
AFWA Cloud Analysis
Assess the accuracy/linearity of radiative transfer in cloudy conditions
IASI, CrIS
More plans…
Thanks for your attention…