A Brief Overview of CO Satellite Products Originally Presented at NASA Remote Sensing Training California Air Resources Board December , 2011 ARSET - AQ Applied Remote SEnsing Training – Air Quality A project of NASA Applied Sciences

CO Measurements from Satellite We will give a brief overview of 5 satellite instruments which currently provide useful measurements of CO.

Satellite Observations of CO CO is  major component of air pollution, produced by fossil fuels, biomass burning, CH 4 oxidation  linked chemically to O 3  an ideal 'tracer'  highly variable geographically and temporally Satellite observations of CO increasingly used for  evaluation of chemical transport models  quantifying CO emissions (inverse modeling)  forecasting air quality and 'Chemical Weather' Merritt Deeter AGU Meeting, San Francisco Dec. 13, 2010

Useful CO Sensors AIRS – Atmospheric Infrared Sounder MOPITT – Measurements of Pollution in The Troposphere TES – Tropospheric Emission Spectrometer SCIAMACHY – Scanning Imaging Absorption Spectrometer for Atmospheric Cartography IASI – Infrared Atmospheric Sounding Interferometer

Pixel and Product Sizes AIRS MOPITT TES SCIAMACHY IASI 30 km 60 km 12 x 12 km Flight direction 45 x 45 km 15 x 15 km 22 x 22 km 8.3 km 5.3 km

CO Satellite Measurements AIRS Daily global coverage. Moderate Spatial Resolution. MOPITT Good Spatial Resolution. ONLY CO product with sensitivity near the ground TES Good Spatial Resolution SCIAMACHY Wide Spectral Range. Poor Spatial Resolution IASI Good Spatial Resolution. 2X a day global coverage.

CO Imagery AIRS – Atmospheric Infrared Sounder AIRS – Near Real Time Image - WMS

CO Imagery TES – Tropospheric Emission Spectrometer

CO Imagery MOPITT – Measurements of Pollution in The Troposphere

The MOPITT Mission MOPITT is 'Measurements of Pollution in the Troposphere' Launched on EOS Terra on Dec. 18, 1999 Still operational! Instrument exploits gas correlation radiometry  CO-filled gas cells act as modulated high spectral resolution optical filters  6 CO channels (4 TIR + 2 NIR) to resolve CO profile, up to 3 pieces of information Courtesy of Merritt Deeter AGU Meeting, San Francisco Dec. 13, 2010

TIR vs. NIR Observations of CO Vertical Resolution of CO TIR vs. NIR Observations of CO Thermal IR observations (MOPITT, AIRS, TES, IASI) sense CO in mid- and upper- troposphere; low 'thermal contrast' limits sensitivity to lower troposphere Near IR observations rely on reflected solar radiation and measure CO total column For retrieving surface-level CO, TIR and NIR observations are complementary MOPITT is only satellite instrument able to make TIR and NIR CO observations Main obstacle to exploiting MOPITT's NIR radiances is understanding random errors Weighting Functions Δ(Radiance)/Δ(CO) Altitude TIR (4.7 μm) NIR (2.3 μm) Courtesy of Merritt Deeter AGU Meeting, San Francisco Dec. 13, 2010

MOPITT Products: V4 vs. V5 Current MOPITT V4 products are based on TIR observations  Thoroughly validated  Poor sensitivity to lower troposphere (true for all TIR products)  Retrieval errors well understood V5 products in development  TIR/NIR products as well as TIR-only and NIR-only products  Algorithm modifications needed to fully exploit NIR radiances  New cloud detection method (see poster A13H-0319)  Release date ~ early 2011 Courtesy of Merritt Deeter AGU Meeting, San Francisco Dec. 13, 2010

V4/V5 Comparisons: 2010 Russian Fires Courtesy of Merritt Deeter AGU Meeting, San Francisco Dec. 13, 2010

V4/V5 Comparisons: 2010 Russian Fires Fires in July/Aug, 2010 affected large areas in central Russia, millions of people MODIS RGB image for Terra overpass on 8/8/2010 shows many fires, dense smoke plume Ural Mountains Scandinavia Black Sea August 8, 2010 Courtesy of Merritt Deeter AGU Meeting, San Francisco Dec. 13, 2010

V4/V5 Comparisons: 2010 Russian Fires MODIS fire counts (black dots) and aerosol distribution reveal source of smoke and resulting smoke plume Resulting CO profile should peak at surface near source region, dissipating downwind Do NIR channels expose source regions? August 8, 2010 Fires Plume Moscow Courtesy of Merritt Deeter AGU Meeting, San Francisco Dec. 13, 2010

V4/V5 Averaging Kernel Comparisons 'Averaging Kernels' describe sensitivity of retrieved profile to true profile: x rtv = x a + A(x true – x a ) AK analysis distinguishes a priori features from information in measurements AKs are standard diagnostics in MOPITT products 'Degrees of Freedom for Signal' quantifies information content, derived from AK matrix V5 surface-level AK indicates much better sensitivity than V4 V4 V5 Courtesy of Merritt Deeter AGU Meeting, San Francisco Dec. 13, 2010

V4/V5 Retrieved Profile Comparisons Properties of V4/V5 retrieved profiles in source region consistent with Aks V5 retrievals indicate extreme CO concentrations at surface with strong variability V4 V5 Courtesy of Merritt Deeter AGU Meeting, San Francisco Dec. 13, 2010

V4/V5 Comparisons: 2010 Russian Fires V4 surface-level CO dominated by a priori V5 product indicates extreme CO concentrations downwind of sources V4V5 Courtesy of Merritt Deeter AGU Meeting, San Francisco Dec. 13, 2010

Timeseries of 2010 Russian Fires Analyzed MODIS and V5 MOPITT products for region between 40 and 45 E, 53 and 58 N MOPITT surface-level CO anomaly only slightly lags onset of fires MOPITT 700 hPa anomaly much smaller than at surface, w/ greater lag MODIS AOD and MOPITT 700 hPa anomaly appear well correlated Courtesy of Merritt Deeter AGU Meeting, San Francisco Dec. 13, 2010

Outlook for MOPITT & TIR/NIR Retrievals Current TIR-based MOPITT V4 products:  Thoroughly validated  Poor sensitivity to lower troposphere 'Multispectral' TIR/NIR retrievals:  Improve vertical resolution  Reveal surface-based CO sources  May enable more accurate air quality forecasting  'Proof of Concept' for future missions (e.g., GEO-CAPE) Courtesy of Merritt Deeter AGU Meeting, San Francisco Dec. 13, 2010