Plans for NearRealTime AIRS L2 Profile Assimilation

1
Plans for Near-Real-Time AIRS L2 Profile
Assimilation

• Shih-Hung Chou and Brad Zavodsky

2
AIRS Specifications

• Aboard Aqua polar orbiter
• Early afternoon equator crossing
• 2378 spectral channels
• 3.7 15.4 µm (650 2675 cm-1)
• 3 x 3 footprints (50 km spatial resolution)
• AMSU allows for retrievals in both clear and
  cloudy scenes
• Version 4.0 Error Estimates (Tobin et al. 2006)
• 0.6-1.0K over ocean ( 50o latitude)
• 0.9-1.3K global ocean and land (in 1 km layers)
• lt 15 RH (in 2 km layers)

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AIRS Data Quality Indicators

• Quality indicators (QIs) in V5
• pressure for each sounding indicating level of
  valid data
• level-by-level error estimates for each T and q
  profile
• Improved retrieval algorithm
• More data are assimilated
• QIs allow for the maximum amount of quality
  data to be assimilated
• assimilating a larger volume of higher quality
  data should produce an analysis that provides
  better initial conditions for the WRF

AIRS V5 PBest from JPL Focus Day
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Near-Real-Time WRF/AIRS SimulationsInitialized
at 00Z 12 km (Using15 nodes)
wrf_real init/brdy
wrf_run to AIRS time 7-h fcst
wrf_prep 40-km NAM (00Z)
Assimilate AIRS data (ARPS)
8 min
30 min
15 min
1.5 h
AIRS data
Products to web
wrf_run (autopost) 41-h fcst
30 min
2 h 10 m/case

• Summary
• Total run time with 1 AIRS case 4 h 40 m
• Each additional case 2 h 10 m
• QPF and RAOB verifications will run when obs
  are available

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Timeline for Near-Real-Time WRF/AIRS
SimulationsInitialized at 00Z 12 km (Using15
nodes)
520Z
620Z
900Z
1240Z
1030Z
1450Z
1520Z
WRF
WRF
Start WRF
CNTL run
AIRS run-2
AIRS run-1
Web products
7-h fcst
7-h fcst
ADAS
700Z
AIRS obs
AIRS on line
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Products to Web

• Daily Posting
• Surface and Pressure-Level Maps T, q, h, and V
• Difference Fields T, q, h, and V
• Delayed Posting
• Verification Statistics RAOB and NAM analysis
• bias and RMSE
• Qualitative Precipitation Forecast Stage IV
  precipitation
• bias score and equitable threat score
• Website NASA GHCC AIRS Assimilation Case Study