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The Use of Hyperspectral Sounding Radiances for Climate Analyses – Experience with AIRS
William L. Smith1,2,3, Elisabeth Weisz1, et. al., 1 University of Wisconsin-Madison 2 NASA/LaRC (SSAI) 3 Hampton University
AIRS Science Team Meeting (13-16 October 2009 Greenbelt MD)
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Objective • Develop and test a “Single Field-of-View” climate variable retrieval method which can be applied to low horizontal resolution (e.g., 100-km) hyperspectral satellite data (e.g., IRIS and CLARREO) as well as high spatial resolution (e.g., 13-km) operational hyperspectral sounder (e.g., AIRS, IASI, CrIS) radiance observations, in order to obtain algorithm independent assessments of climate change.
• Test this algorithm using 6-years (2003-2008) AIRS radiance data
• Validate this algorithm using ECMWF (ERA-Interim) re-analyses of global observing system (satellite plus conventional) data and intercomparing the 100-km FOV product with that obtained from full resolution (13-km) AIRS data.
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“Climate” Single FOV Technique “Clear-trained” and “Cloud-trained” EOF regression IR hyperspectral sounder retrievals of: surface skin temperature, CO2 concentration, cloud top altitude, effective cloud optical depth, and atmospheric temperature, moisture, and ozone profiles above the cloud and below thin or scattered cloud (i.e., cloud effective optical depth < 1.5 and a cloud induced temperature attenuation < 15 K.
1. Cloud height: Level where “cloud-trained” temperature profile retrieval becomes systematically greater than the “clear-trained” temperature profile retrieval. (The Cloud-trained EOF regression solution coefficients are selected from a set of ten classes of cloud-height stratified 200-hPa overlapping layers. The proper class is determined using a non-linear (i.e., iterative) cloud pressure regression estimator. The initial value is determined using an unclassified by cloud height linear regression operator.)
2. Cloud optical depth: Estimated using classified EOF regression 3. Atmospheric profile:
a) above the cloud: “clear-trained” retrieval b) below the cloud: “cloud-trained” retrieval
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1500 Channels Used
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AIRS Cloud Height & T/RH Profile Examples (1) T-cloud: Highest level where Tcld(p) >Tclr(p) to the ground where Tcld(p) & Tclr(p) obtained by EOF regression (2) RH-cloud: Highest RHclr peak > 75% (3) Profile cloud height taken as (1) above (4) T = Tclr & RH = RHclr above cloud (5) If [“Optical Depth” <= 1.5 & Max [(Tcld (p) – Tclr (p)] < 15K then the below cloud profiles are.: T(p) = Tcld(p) and RH(p) = RHcld(p) Otherwise: T(p) & RH(p) = “missing”
Cloud and Profile Determination:
AIRS-T = 661-hPa AIRS-RH = 684-hPa CALIPSO = 680-hPa CloudSat= 718-hPa
RH-profile senses optically thin cirrus T-profile senses lower cloud
34 S, 87 W
AIRS-T = 778-hPa AIRS-RH = 103-hPa CALIPSO = 101-hPa CloudSat = 717-hPa
10 S, 124E
AIRS-T = 118-hPa AIRS-RH = 103-hPa CALIPSO = 94-hPa CloudSat = 115-hPa
11 N, 193 E
August 7, 2007 “Cloud-Trained”
“Clear Trained”
“Combined”
August 7, 2007
“Cloud-Trained”
“Clear Trained”
“Combined”
50 100% Relative Humidity
50 100% Relative Humidity
50 100% Relative Humidity
“Cloud-Trained”
“Clear Trained”
“Combined”
Temperature
Temperature Temperature
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AIRS-T, AIRS-RH, CALIPSO, & CloudSat Highest Co-located AIRS FOV Cloud Altitudes (2.5 deg. grid average)
AIRS-T Cld Ht (Aug. 7, 2007) CloudSat Cld Ht (Aug. 7, 2007)
CALIPSO Cld Ht (Aug 7, 2007) AIRS-RH Cld Ht (Aug. 7, 2007)
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Inter-comparison Criteria (AIRS, CALIPSO, and CloudSat co-located* fields of view)
• MODIS Clear Probability = 0%
• IIR FOV average radiance difference ≤ 1 %
• CALIPSO Number of Cloud Layers ≤ 2
* Co-locations provided by Nagle and Holz (UW-CIMSS)
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IR-Profile Vs CALIPSO Cloud Height
IR-Profile Vs CloudSat Cloud Height
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AIRS-T
CALIPSO
CALIPSO Vs CloudSat Cloud Height
AIRS-T Vs CloudSat Cloud Height
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2003‐2008 Monthly Mean Temperature
and Rela7ve Humidity
for February and August
(Nadir AIRS/”CLARREO” Vs ECMWF)
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Simula2ng “CLARREO” Data from AIRS
• Use Nadir‐only samples
• “CLARREO” = 6 x 6 average (≈100‐km resolu7on and spacing) AIRS Measurements
• “AIRS” = Clearest of six (≈ 13‐km resolu7on and 100‐km spacing)
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850 hPa Temperature (2003‐2008) February
ECMWF 850 hPa Temperature
ECMWF 850 hPa Temperature
AIRS 850 hPa Temperature
AIRS 850 hPa Temperature
February
August August
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February
ECMWF 850 hPa Temperature
ECMWF 850 hPa Temperature
August
February
CLARREO 850 hPa Temperature
850 hPa Temperature (2003‐2008)
August
CLARREO 850 hPa Temperature
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850 hPa Humidity (2003‐2008)
ECMWF 850 hPa Rela7ve Humidity
ECMWF 850 hPa Rela7ve Humidity AIRS 850 hPa Rela7ve Humidity
AIRS 850 hPa Rela7ve Humidity
February February
August August
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850 hPa Humidity (2003‐2008)
ECMWF 850 hPa Rela7ve Humidity
ECMWF 850 hPa Rela7ve Humidity
February
August
February
CLARREO 850 hPa Rela7ve Humidity
August
CLARREO 850 hPa Rela7ve Humidity
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500 hPa Temperature (2003‐2008)
ECMWF 500 hPa Temperature
ECMWF 500 hPa Temperature
AIRS 500 hPa Temperature
February February
August August
AIRS 500 hPa Temperature
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500 hPa Temperature (2003‐2008)
ECMWF 500 hPa Temperature
ECMWF 500 hPa Temperature
February
August
February
CLARREO 500 hPa Temperature
August
CLARREO 500 hPa Temperature
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500 hPa Humidity (2003‐2008)
ECMWF 500 hPa Rela7ve Humidity
ECMWF 500 hPa Rela7ve Humidity AIRS 500 hPa Rela7ve Humidity
AIRS 500 hPa Rela7ve Humidity
February February
August August
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500 hPa Humidity (2003‐2008)
ECMWF 500 hPa Rela7ve Humidity
ECMWF 500 hPa Rela7ve Humidity
February
August
February
CLARREO 500 hPa Rela7ve Humidity
August
CLARREO 500 hPa Rela7ve Humidity
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300 hPa Temperature (2003‐2008)
ECMWF 300 hPa Temperature
ECMWF 300 hPa Temperature
AIRS 300 hPa Temperature
AIRS 300 hPa Temperature
February February
August August
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300 hPa Temperature (2003‐2008)
ECMWF 300 hPa Temperature
ECMWF 300 hPa Temperature
February
August
February
CLARREO 300 hPa Temperature
August
CLARREO 300 hPa Temperature
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300 hPa Humidity (2003‐2008)
ECMWF 300 hPa Rela7ve Humidity
ECMWF 300 hPa Rela7ve Humidity AIRS 300 hPa Rela7ve Humidity
AIRS 300 hPa Rela7ve Humidity
February February
August August
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300 hPa Humidity (2003‐2008)
ECMWF 300 hPa Rela7ve Humidity
ECMWF 300 hPa Rela7ve Humidity
February
August
February
CLARREO 300 hPa Rela7ve Humidity
August
CLARREO 300 hPa Rela7ve Humidity
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50 hPa Temperature (2003‐2008)
ECMWF 50 hPa Temperature
ECMWF 50 hPa Temperature
AIRS 50 hPa Temperature
AIRS 50 hPa Temperature
February February
August August
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50 hPa Temperature (2003‐2008)
ECMWF 50 hPa Temperature
ECMWF 50 hPa Temperature
February
August August
CLARREO 50 hPa Temperature
February
CLARREO 50 hPa Temperature
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2003‐2008 “Annual” (February + August)
Mean Temperature
and Rela7ve Humidity
6‐yr Trend (Nadir AIRS/CLARREO Vs ECMWF)
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850 hPa 6‐Year Trend (2003‐2008)
6‐year Trend
AIRS 850 hPa Rela7ve Humidity
6‐Year Trend
ECMWF 850 hPa Rela7ve Humidity
6‐year Trend
ECMWF 850 hPa Temperature
6‐year Trend
AIRS 850 hPa Temperature
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850 hPa 6‐Year Trend (2003‐2008)
6‐Year Trend
ECMWF 850 hPa Rela7ve Humidity
6‐year Trend
ECMWF 850 hPa Temperature
6‐year Trend
CLARREO 850 hPa Temperature
6‐year Trend
CLARREO 850 hPa Rela7ve Humidity
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500 hPa 6‐Year Trend (2003‐2008) 6‐year Trend
AIRS 500 hPa Temperature
6‐year Trend
AIRS 500 hPa Rela7ve Humidity
6‐year Trend
ECMWF 500 hPa Rela7ve Humidity
6‐year Trend
ECMWF 500 hPa Temperature
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500 hPa 6‐Year Trend (2003‐2008)
6‐year Trend
ECMWF 500 hPa Rela7ve Humidity
6‐year Trend
ECMWF 500 hPa Temperature
6‐year Trend
CLARREO 500 hPa Temperature
6‐year Trend
CLARREO 500 hPa Rela7ve Humidity
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300 hPa 6‐Year Trend (2003‐2008) 6‐year Trend
AIRS 300 hPa Temperature
6‐year Trend
AIRS 300 hPa Rela7ve Humidity
6‐year Trend
ECMWF 300 hPa Rela7ve Humidity
6‐year Trend
ECMWF 300 hPa Temperature
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300 hPa 6‐Year Trend (2003‐2008)
6‐year Trend
ECMWF 300 hPa Rela7ve Humidity
6‐year Trend
ECMWF 300 hPa Temperature
6‐year Trend
CLARREO 300 hPa Temperature
6‐year Trend
CLARREO 300 hPa Rela7ve Humidity
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50 hPa 6‐Year Trend (2003‐2008) 6‐year Trend
AIRS 50 hPa Temperature
6‐year Trend
AIRS 50 hPa Rela7ve Humidity
6‐year Trend
ECMWF 50 hPa Rela7ve Humidity
6‐year Trend
ECMWF 50 hPa Temperature
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50 hPa 6‐Year Trend (2003‐2008)
6‐year Trend
ECMWF 50 hPa Rela7ve Humidity
6‐year Trend
ECMWF 50 hPa Temperature
6‐year Trend
CLARREO 50 hPa Temperature
CLARREO 50 hPa Rela7ve Humidity
6‐year Trend
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Global Mean Trends (ECMWF Vs AIRS Vs CLARREO)
Parameter ECMWF AIRS CLARREO Difference
850 T (K/yr) ‐0.029 ‐0.120 ‐0.198 ‐0.078
850 RH (%/ yr) +0.154 ‐0.366 ‐0.361 +0.005
500 T ‐0.021 ‐0.123 ‐0.125 ‐0.002
500 RH +0.073 ‐0.078 ‐0.106 ‐0.028
300 T ‐0.006 ‐0.070 ‐0.066 +0.006
300 RH ‐0.093 +0.071 +0.052 ‐0.019
50 T +0.013 ‐0.027 ‐0.026 ‐0.001
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Summary & Conclusion • ECMWF ERA must be very good. Compares well with
independent satellite product (i.e., Dual EOF Regn AIRS)
• Dual EOF Regression Single FOV Retrieval works well - 100-km FOV compares well to 13-km FOV
• Amazing correspondence between monthly mean values of twice per day Nadir AIRS and CLARREO proxy retrievals with ECMWF analyses of all GOS data
– Regional Monthly Means – Regional 6-year trends in “Annual” Mean
• Next step: Produce 5-Decade regional trend results from 1970 IRIS hyperspectral FTS data and AIRS/IASI data degraded to IRIS spectral (1.4 cm-1, unapodized) and spatial (100-km) resolution.
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2003‐2006 Comparisons of Results with AIRS Science Team
Temperature and
Rela7ve Humidity
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Dual Regn AIRS/CLARREO, ScTm AIRS+AMSU, ECMWF (2003‐2008)
6‐yr “Annual” (Feb + Aug) Mean
ECMWF 850 hPa Temperature S‐team AIRS 850 hPa Temperature
6‐yr “Annual” (Feb + Aug) Mean
DReg CLARREO 850 hPa Temperature
6‐yr “Annual” (Feb + Aug) Mean
DReg AIRS 850 hPa Temperature
6‐yr “Annual” (Feb + Aug) Mean
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Dual Regn AIRS/CLARREO, ScTm AIRS+AMSU, ECMWF (2003‐2008)
S‐team AIRS 500 hPa Temperature
6‐yr “Annual” (Feb + Aug) Mean 6‐yr “Annual” (Feb + Aug) Mean
ECMWF 500 hPa Temperature
DReg CLARREO 500 hPa Temperature
6‐yr “Annual” (Feb + Aug) Mean
DReg AIRS 500 hPa Temperature
6‐yr “Annual” (Feb + Aug) Mean
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Dual Regn AIRS/CLARREO, ScTm AIRS+AMSU, ECMWF (2003‐2008)
S‐team AIRS 300 hPa Temperature
6‐yr “Annual” (Feb + Aug) Mean 6‐yr “Annual” (Feb + Aug) Mean
ECMWF 300 hPa Temperature
DReg CLARREO 300 hPa Temperature
6‐yr “Annual” (Feb + Aug) Mean
DReg AIRS 300 hPa Temperature
6‐yr “Annual” (Feb + Aug) Mean
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Dual Regn AIRS/CLARREO, ScTm AIRS+AMSU, ECMWF (2003‐2008)
S‐team AIRS 50 hPa Temperature
6‐yr “Annual” (Feb + Aug) Mean 6‐yr “Annual” (Feb + Aug) Mean
ECMWF 50 hPa Temperature
DReg CLARREO 50 hPa Temperature
6‐yr “Annual” (Feb + Aug) Mean
DReg AIRS 50 hPa Temperature
6‐yr “Annual” (Feb + Aug) Mean
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Dual Regn AIRS/CLARREO, ScTm AIRS+AMSU, ECMWF (2003‐2008)
S‐team AIRS 850 hPa Humidity
6‐yr “Annual” (Feb + Aug) Mean 6‐yr “Annual” (Feb + Aug) Mean
ECMWF 850 hPa Humidity
DReg CLARREO 850 hPa Humidity
6‐yr “Annual” (Feb + Aug) Mean
DReg AIRS 850 hPa Humidity
6‐yr “Annual” (Feb + Aug) Mean
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Dual Regn AIRS/CLARREO, ScTm AIRS+AMSU, ECMWF (2003‐2008)
S‐team AIRS 500 hPa Humidity
6‐yr “Annual” (Feb + Aug) Mean 6‐yr “Annual” (Feb + Aug) Mean
ECMWF 500 hPa Humidity
DReg CLARREO 500 hPa Humidity
6‐yr “Annual” (Feb + Aug) Mean
DReg AIRS 500 hPa Humidity
6‐yr “Annual” (Feb + Aug) Mean
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Dual Regn AIRS/CLARREO, ScTm AIRS+AMSU, ECMWF (2003‐2008)
S‐team AIRS 300 hPa Humidity
6‐yr “Annual” (Feb + Aug) Mean 6‐yr “Annual” (Feb + Aug) Mean
ECMWF 300 hPa Humidity
DReg CLARREO 300 hPa Humidity
6‐yr “Annual” (Feb + Aug) Mean
DReg AIRS 300 hPa Humidity
6‐yr “Annual” (Feb + Aug) Mean
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Trend Comparisons
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6‐Year “Annual” Trend (2003‐2008)
DReg AIRS 850 hPa Temperature
6‐yr “Annual” (Feb + Aug) Trend
6‐yr “Annual” (Feb + Aug) Trend
ECMWF 850 hPa Temperature
DReg CLARREO 850 hPa Temperature
6‐yr “Annual” (Feb + Aug) Trend
S‐team AIRS 850 hPa Temperature
6‐yr “Annual” (Feb + Aug) Trend
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6‐Year “Annual” Trend (2003‐2008)
6‐yr “Annual” (Feb + Aug) Trend
ECMWF 850 hPa Humidity
DReg AIRS 850 hPa Humidity
6‐yr “Annual” (Feb + Aug) Trend
DReg CLARREO 850 hPa Humidity
6‐yr “Annual” (Feb + Aug) Trend
S‐team AIRS 850 hPa Humidity
6‐yr “Annual” (Feb + Aug) Trend
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6‐Year “Annual” Trend (2003‐2008)
6‐yr “Annual” (Feb + Aug) Trend
ECMWF 500 hPa Temperature
DReg CLARREO 500 hPa Temperature
6‐yr “Annual” (Feb + Aug) Trend
DReg AIRS 500 hPa Temperature
6‐yr “Annual” (Feb + Aug) Trend
S‐team AIRS 500 hPa Temperature
6‐yr “Annual” (Feb + Aug) Trend
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6‐Year “Annual” Trend (2003‐2008)
6‐yr “Annual” (Feb + Aug) Trend
ECMWF 500 hPa Humidity
DReg CLARREO 500 hPa Humidity DReg AIRS 500 hPa Humidity
6‐yr “Annual” (Feb + Aug) Trend 6‐yr “Annual” (Feb + Aug) Trend
S‐team AIRS 500 hPa Humidity
6‐yr “Annual” (Feb + Aug) Trend
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6‐Year “Annual” Trend (2003‐2008)
6‐yr “Annual” (Feb + Aug) Trend
ECMWF 300 hPa Temperature
DReg AIRS 300 hPa Temperature
6‐yr “Annual” (Feb + Aug) Trend
DReg CLARREO 300 hPa Temperature
6‐yr “Annual” (Feb + Aug) Trend
S‐team AIRS 300 hPa Temperature
6‐yr “Annual” (Feb + Aug) Trend
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6‐Year “Annual” Trend (2003‐2008)
6‐yr “Annual” (Feb + Aug) Trend
ECMWF 300 hPa Humidity
DReg AIRS 300 hPa Humidity
6‐yr “Annual” (Feb + Aug) Trend
DReg CLARREO 300 hPa Humidity
S‐team AIRS 300 hPa Humidity
6‐yr “Annual” (Feb + Aug) Trend
6‐yr “Annual” (Feb + Aug) Trend
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6‐Year “Annual” Trend (2003‐2008)
6‐yr “Annual” (Feb + Aug) Trend
ECMWF 50 hPa Temperature
DReg AIRS 50 hPa Temperature
6‐yr “Annual” (Feb + Aug) Trend
DReg CLARREO 50 hPa Temperature
6‐yr “Annual” (Feb + Aug) Trend
S‐team AIRS 50 hPa Temperature
6‐yr “Annual” (Feb + Aug) Trend