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Advanced Sounder Capabilities- Airborne Demonstration with NAST-I

Advanced Sounder Capabilities- Airborne Demonstration with NAST-I W.L. Smith, D.K. Zhou, and A.M. Larar NASA Langley Research Center, Hampton, Virginia 23681 Twelfth International TOVS Study Conference (Lorne Australia, 27 Feb-5 Mar, 2002). NAST on Proteus. ER-2.

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Advanced Sounder Capabilities- Airborne Demonstration with NAST-I

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  1. Advanced Sounder Capabilities- Airborne Demonstration with NAST-I W.L. Smith, D.K. Zhou, and A.M. Larar NASA Langley Research Center, Hampton, Virginia 23681 Twelfth International TOVS Study Conference (Lorne Australia, 27 Feb-5 Mar, 2002) NAST on Proteus ER-2 Performance:Ceiling 65-75 kft Airspeed 300 ktas Endurance 12-22 hrs Operating Altitude: 100 to 60,000 ft

  2. NPOESS Airborne Sounder Testbed (NAST) IR interferometer ( NAST-I ) Spectral Range:3.5 – 16microns Spectral Resolution:>2000 (0.25cm-1)

  3. Spectral Coverage Comparison NAST-I /IASI CrIS AIRS/CrIS GIFTS-LW GIFTS-SW GIFTS CO CO CO2 N2O N2OCH4 H2O N2O CH4 H2O H2O N2O CO2 H2O CO2 O3 O3 CO2 H2O NAST-I Spectral Coverage Encompasses all future satellite sounders

  4. NAST-I Observes 3-Dimensional Structure With High Spatial Resolution and Radiometric Accuracy p

  5. Optimal Regression Retrieval Approach for NAST-I Application • R = radiance • = surface emissivity Bs = surface Planck radiance • = transmittance • s = surface transmittance • * = (s)2 /  Ps = surface pressure Pac = aircraft pressure S = number of sample profiles  = radiance deviation from the mean M = covariance matrix of  E = eigenvectors of M – EOFs C = radiance EOF amplitudes A = {Ts, , T, q, ...} parameters K and k = regression coefficients  = emissivity EOF amplitudes

  6. NAST-I Spectrum and Retrieval Channels NAST-I Spm RTVL Chnls

  7. Retrieval Accuracy Vs EOF Number 10 Full Noise 26 58 1/2 Noise

  8. Observed Vs Calculated from Retrieval

  9. Retrievals for Two Different EOF #s 48 EOFs Radiosonde 23 EOFs

  10. Radiosonde Validation Andros Is. Bahamas, Sept 12, 1998 Raob NAST Altitude (km) Relative Humidity (%) 3km Distance (75 km)

  11. Spectral H2O Sensitivity H2O Sensitivity [dTB(,p)/dlnq(p)]

  12. Water Vapor Retrieval Sensitivity LW-side of H2O Band 75 km SW-side of H2O Band

  13. Spatial (~22km) & Temporal (~2-3hr) Temperature Variation Over Purcell ARM CART-Site Sounding Validation C P D Sfc Temp (21Z) A P B Space & Time Variability Sfc Temp (19Z)

  14. PROTEUS NAST-I Flight Over CART SiteLoop 1 [18:06 – 19:50 UT, March 19, 2000]

  15. PROTEUS/NAST-I Flight Over CART SiteLoop 2 [19:50 – 21:24 UT, March 19, 2000]

  16. VERTICAL PROFILE COMPARISONS NOV 30 NOV 30 NOV 30 DEC 05 DEC 05 DEC 05

  17. COMPARISON WITH GSFC-SRL (DEC. 5, 2000) Loss of Sensitivity NAST-I cross section is produced by profiles from 7 high altitude passes over Lamont OK. GSFC-SRL Ground-based Scanning Raman LIDAR produced from 10 min averages at Lamont OK Time Average

  18. Wallops Island Va. to Dryden Ca. (8/27/99)

  19. Proteus NAST-I Vertical Cross-section (CLAMS 7/12/01) 16.0 UTC 13.8 14.9 This flight demonstrates the ability to observe the spatial moisture structure below a scattered and semi-transparent Cirrus cloud cover

  20. Effective Surface Temperature (July 26, 2001) GOES image High dense convective clouds over North Carolina and low cumulus clouds over the Delmarva peninsula

  21. Effective Cloud Properties (July 26, 2001)

  22. Vertical Cross-section (July 26, 2001) Clouds Clouds CLOUDS CLOUDS CLOUDS Clouds IR Window Image Along Track

  23. Surface Skin Temperature (July 14, 2001) 296.52º K ( = 0.54º K)NAST-I retrieved (within 0.1 Lat. and Lon.) 297.45º K NOAA buoy site CHLV2 measured (i.e., the bulk SST). The cool “skin”, observed by NAST-I, relative to the sub-surface water, observed by the buoy, is expected as a result of evaporative cooling.

  24. Surface Emissivity (July 14, 2001) Seawater Emissivity Lab. measured (solid) NAST-I retrieved (dashed) NAST-I validation (dots)

  25. Surface Skin Temperature Along Track IR Image along track NPOESS Aircraft Sounding Testbed (NAST) soundings over Alaska from the ~15km flight altitude of the Proteus (March 20-21, 2001). Upper panels show flight track and cross-section. (Note the updrafts and downdrafts seen in the water vapor at 7-9 km.) Bottom panels show comparisons with North Slope CART-site radiosondes. March 20, 2001 March 21, 2001

  26. Can CAT Be Measured ? Temp NAST Near Fairbanks AK (3/21/01; 1-2 GMT) 200 km Moisture Weak Turbulence Signatures at 150 mb Downdrafts:Warm&Dry Updrafts:Cold & Moist Temp Moisture Strong Turbulence Signatures at 300 mb Temp Moisture Moisture No Turbulence Signatures at 500 mb

  27. Summary • The NAST provides high spatial resolution radiance measurements which can be used to validate the radiometric accuracy and retrieval products of advanced IR sounding systems • High spatial resolution features of atmospheric temperature, moisture, and clouds can be retrieved from NAST radiances • Lower tropospheric water vapor profiles depend on measurements along the shortwave side of the 6.3 m H2O band • High spectral/spatial resolution sounders can profile above an opaque overcast cloud cover and above and below thin and/or broken clouds • Surface skin temperature and emissivity can be retrieved simultaneously from the spectral radiance measurements and this is important for the retrieval of accurate lower tropospheric moisture profiles • Atmospheric turbulence might be observed with very high spatial resolution advanced sounders

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