Remote Sensing of CO from AIRS AIRS typically sees 82% of the globe each day

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1 Remote Sensing of CO from AIRS 14 AIRS typically sees 82% of the globe each day From McMillan, et. al., AIRS Science Team Meeting, Spring, 2004

2 Addressing Aerosol / CO Interactions Sub-Saharan biomass burning Savanna, open forest fires Inefficient burning, high CO emissions High soot, ash emissions Asian biomass burning mixed with pollution Fires in boreal forests of Russia Inefficient burning, high CO emissions High soot, ash & particulate emissions Asian dust mixed with pollution High coarse aerosol loading Mineral dust advected from large desert regions in Asia and Mongolia Low CO unless mixed with pollution Aerosols (fine mode) and CO are both components of combustion A focus of current scientific interest is understanding intercontinental transport of aerosol and trace gases 15

3 Co-Located CO/Aerosol Analysis Sub-Saharan Biomass Burning Fine Mode Aerosol Optical Depth High CO concentration High aerosol optical depth Find strong correlation between AOD fine /CO Biomass burning less efficient than fossil fuel burning smoldering phase high CO emissions, low CO 2 emissions Total Aerosol Optical Depth R 2 =0.47 Total Column CO Fine Mode Aerosol Optical Depth R 2 =

4 Asian Biomass Burning and Pollution Event MODIS Image from 5/8/03 MODIS image shows smoke from Russian fires transported over China and Japan on May 8, 2003 Considered three regions in image 1) Boreal forest biomass burning 2) Pollution 3) Dust mixed with pollution Total Column CO Fine Mode Aerosol Optical Depth 17

5 Good Correlation between CO and Biomass Burning Smoke 1 Fine Mode Aerosol Optical Depth R 2 =0.42 High CO and large AOD fine Good correlation between AOD fine /CO Meets expectation of high CO with heavy aerosol loading for biomass burning Biomass Burning Mode 18

6 Air Pollution Fits Other Mode High AOD fine and moderate CO Beijing is within this region Fine Mode Aerosol Optical Depth 2 Pollution Mode R 2 =0.25 Biomass Burning Mode For low AOD fine levels, we see linear increase in CO For large AOD fine, we see fairly constant CO levels of about 2.8x10 18 mol cm -2 Contend this is back-ground pollution level 19

7 Future Developments in Remote Sensing of Aerosols and Trace Gases 20

8 Future Developments in Remote Sensing of Aerosols and CO SIRAS-G: Spaceborne Infrared Atmospheric Sounder for Geosynchronous Orbit SIRAS-G is an instrument concept for infrared sounding at a moderate spectral resolution (λ/ λ) of , operating from µm Grating spectrometers provide fine spectral separation The flight instrument divides this spectral range into 4 spectrometer channels Being developed at Ball under NASA s Instrument Incubator Program Size Mass Power Rate SIRAS-L 0.13 m 3 50 kg 100W 1.42 Mbps SIRAS-G 0.19 m 3 50 kg 100W 2.5 Mbps Table 1. SIRAS-G Grating Spectrometers Spect Band (µm) Comments Design in 2003 IIP Design in 2003 IIP Build in 2003 IIP Built in 1999 IIP Pulse Tube Cooler* (IMAS) Cold Link Radiators for Cooler & Optics Focal Planes and Dewars (4) * Mini Spectrometers* (4) Telescope Scanner Structure (+thermal barriers) Solar Baffle * Common Spectrometer, FPA, Dewar, and Cooler Design for LEO or GEO 21

9 Potential Follow-On To AIRS SIRAS was originally conceived as a smaller, lower mass, less costly follow-on instrument for AIRS SIRAS replaces the single large AIRS with 4 spectrometer modules 22 Low Dispersion Grating used In high orders AIRS Spectrometer µm µm µm µm SIRAS Spectrometers High Dispersion Grating used In low orders Diffraction Limited Aperture* Wide Field Diffractive Optics 4 Spectrometer Modules used to cover the 3.4 to 15.4 microns spectral range This leads to reduced total mass, volume and power

10 SIRAS-1999 IIP - What Was Achieved? The LLWIR ( µm) spectrometer designed, built and cryogenically tested Selected the LLWIR spectrometer since it represented the greatest challenge (material choices, detector cut-off, etc.) Developed test facilities for testing the spectrometer at cryogenic temperatures Integrated an AIRS M1 detector array (on-loan from the AIRS program) and used a detector test set loaned from LMIRS Developed data collection and control software This effort completed in 12- months Camera Lens Assembly Cooled Detector Assembly Grating Collimator Lens Assembly Measured data compared to theoretical 3-m path atmospheric transmission spectra with varying spectral response widths Response widths were varied until the resulting convolved modeled spectra matched the measured spectra Measured CO 2 spectra show spectral resolution (>900) achieved 23

11 SIRAS-G Program Goals The purpose of the SIRAS-G IIP program is to further develop the SIRAS concept and build a laboratory hardware demonstration Demonstrate an workable end-to-end system incorporating new technologies including: Refractive grating spectrometers Optically-Enhanced FPA Dewar Active Cooling Demonstrate high spectral purity of grating-based instrument (low spectral smile and keystone distortion) Increase Technology Readiness from TRL-3 to TRL-5 or 6 Demonstrate that spectral range and resolution can be optimized for specific science goals (atmospheric sounding, climate studies) Telescope SB235 Stirling Cryocooler compressor Optical Bench Vacuum pump Vacuum housing SB235 Cryocooler Stirling displacer Layout of the SIRAS-G Laboratory Demo Instrument EOS Terra, Aqua MODIS - 1 km IR IFOV µm IR - 16 IR Chann els - λ/ λ = NEdT = K - Refractive Optics -± 55 FOV The Spaceborne Infrared Atmospheric Sounder for LEO (SIRAS-L) Future Concept SIRAS-L km IR IFOV µm IR IR Channels - λ/ λ = Refractive Optics - Gr ati ng Spectrom eter - NEdT = K - 15 FOV EOS, Aqua AIRS km IR IFOV µm IR IR Channels - λ/ λ = Grating Spectrometer - NEdT = K -± 50 FOV 24

12 Supplementary Instrument: IMOFPS Simulated Mid-Latitude Spectrum for CO Imaging Multi-Order Fabry-Perot Spectrometer Imaging Optics Cold Stop Anamorphic Telescope Relay Correlation Filter Cross-track (imaging) 25 Arbitrary Units Arbitrary Units FSR FSR CO spectrum CO spectrum Etalon transmission Etalon transmission Wavenumber (cm -1 ) Wavenumber (cm -1 ) Etalon Free Spectral Range Mis-Match with Etalon Spectral Free Spectral Lines (CO Range Example) Mis-Match with Spectral Lines (CO Example) Correlation Filter Matches Several Spectral Lines to within ±0.02cm -1 Along-track imaging provides spectral sampling along lines On-axis response Conventional F-P (Note Etalon Trans Function mismatched after a couple of lines Lines contaminated by other species avoided IMOFPS is a high spectral resolution (0.1 cm -1 ) spectrometer tuned to sample the absorption spectra of key trace gases IMOFPS increases the useable FOV over that of a conventional Fabry-Perot In addition, the unique correlation filter design provides excellent matching of the instrument transmission function to the non-periodic gas absorption features Off-axis response Patent Applications have been filed by Ball Patent Applications have been filed by Ball Aerospace for the IMOFPS Correlation Aerospace for the IMOFPS Correlation Filter and Anamorphic Optical System Filter and Anamorphic Optical System

13 Conclusions and Summary Combined measurements from current and nextgeneration high spectral-resolution IR sensors will play an increasingly more important role in our understanding of tropospheric chemistry and transport processes A better understanding of the sources and transport of aerosols and CO will provide information continental transport and the impact of biomass burning on air quality, chemistry, and pollution Accurate satellite measurements are complimentary to ground-based measurements. Integrating these both with chemistry transport models (data assimilation) will provide an even more complete picture of tropospheric processes Aerosols have a significant impact on TOA radiances in the Mid-IR and must be accounted for to obtain accurate trace gas retrievals 26