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Paul Palmer, University of Leeds env.leeds.ac.uk/~pip

What can we learn about the Earth system using space-based observations of tropospheric chemical composition?. Paul Palmer, University of Leeds www.env.leeds.ac.uk/~pip. + UK/European missions + CMDL network = sparse data coverage. hv. O 3. NO 2. NO. OH. HO 2. HC+OH  HCHO + products.

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Paul Palmer, University of Leeds env.leeds.ac.uk/~pip

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  1. What can we learn about the Earth system using space-based observations of tropospheric chemical composition? Paul Palmer, University of Leeds www.env.leeds.ac.uk/~pip

  2. + UK/European missions + CMDL network = sparse data coverage

  3. hv O3 NO2 NO OH HO2 HC+OH  HCHO + products Tropospheric O3 is an important climate forcing agent NOx, HC, CO Level of Scientific Understanding Natural VOC emissions (50% isoprene) ~ CH4 emissions. IPCC, 2001

  4. Pierce et al, JGR, 1998 EPA BEIS2 MEGAN 2.6 Tg C [1012 atom C cm-2 s-1] 3.6 Tg C Bottom-up Isoprene emissions, July 1996 E = A∏iγi Emissions (x,y,t); fixed base emissions(x,y); sensitivity parameters(t) Guenther et al, JGR, 1995 GEIA 7.1 Tg C Guenther et al, ACP, 2006

  5. Global Ozone Monitoring Experiment (GOME) &the Ozone Monitoring Instrument (OMI) Launched in 2004 • GOME (European), OMI (Finnish/USA) are nadir SBUV instruments • Ground pixel (nadir): 320 x 40 km2 (GOME), 13 x 24 km2 (OMI) • 10.30 desc (GOME), 13.45 asc (OMI) cross-equator time • GOME: 3 viewing angles  global coverage within 3 days • OMI: 60 across-track pixels  daily global coverage • O3, NO2, BrO, OClO, SO2, HCHO, H2O, cloud properties

  6. 0.5 2 2.5 1 0 1.5 [1016 molec cm-2] GOME HCHO columns Biogenic emissions Biomass burning July 2001 Data: c/o Chance et al * Columns fitted: 337-356nm * Fitting uncertainty < continental signals

  7. May Jun Jul Aug Sep 1996 1997 1998 1999 2000 2001 GOME HCHO column [1016 molec cm-2] 0.5 2 2.5 1 0 1.5 Palmer et al, JGR, 2006.

  8. Tropospheric chemistry: a highly non-linear system, e.g. isoprene chemistry Yield dependent on oxidant concentrations • Models typically use a simplified (lumped) oxidation mechanism • Assimilating HCHO possible but involves integrating many 100s of uncertain chemical reactions • Neglected to mention other (more chemically uncertain) biogenic sources of HCHO! • For now, we can extract lots of information from the HCHO using a simple method…

  9. hours hours HCHO h, OH OH kHCHO ___________ HCHO EVOC = (kVOCYVOCHCHO) WHCHO Isoprene a-pinene propane 100 km Distance downwind VOC source Relating HCHO Columns to VOC Emissions VOC Net Local linear relationship between HCHO and E EVOC: HCHOfromGEOS-CHEM CTM and MEGAN isoprene emission model Palmer et al, JGR, 2003.

  10. Seasonal Variation of Y2001 Isoprene Emissions May Aug Jun Sep 1012 atom C cm-2s-1 Jul 7 0 3.5 MEGAN GOME MEGAN GOME • Good accord for seasonal variation, regional distribution of emissions (differences in hot spot locations – implications for O3 prod/loss). • Other biogenic VOCs play a small role in GOME interpretation Palmer et al, JGR, 2006.

  11. May Jun Jul Aug Sep 1996 1997 1998 1999 2000 Relatively inactive 2001 [1012 molecules cm-2s-1] 10 0 5 GOME Isoprene Emissions: 1996-2001 Palmer et al, JGR, 2006.

  12. MEGAN Obs GOME Isoprene flux [1012 C cm-2 s-1] Julian Day, 2001 Sparse ground-truthing of GOME HCHO columns and derived isoprene flux estimates Seasonal Variation: Comparison with eddy correlation isoprene flux measurements (B. Lamb) is encouraging May Jun July Aug Sep Atlanta, GA 199619971998199920002001 PROPHET Forest Site, MI Atlanta, GA GOME HCHO [1016 molec cm-2] Interannual Variation: Correlate with EPA isoprene surface concentration data. Outliers due to local emissions. PAMS Isoprene, 10-12LT [ppbC]

  13. Surface temperature explains 80% of GOME-observed variation in HCHO G98 fitted to GOME data GOME HCHO Slant Column [1016 molec cm-2] G98 Modeled curves NCEP Surface Temperature [K] Palmer et al, JGR, 2006. Time to revise model parameterizations of isoprene emissions?

  14. Tropical ecosystems represent 75% of biogenic NMVOC emissions 1996 1997 1998 1999 2000 2001 What controls the variability of NMVOC emissions in tropical ecosystems? Kesselmeier, et al, 2002 Importance of VOC emissions in C budget? GOME HCHO column, July

  15. OMI, 24/9-19/10, 2004 13x24 km2 monoterpene emission of Apeiba tibourbou 1500 40 [°C] 1000 30 (µmol m-2 s-1) PAR temperature 500 20 10 6 limonene myrcene 5 b-pinene a-pinene 4 sabinene [sum of monoterpenes] emission rate (C) G93 for isop. (µg g-1 h-1) 3 2 1 0 4 4 (mmol m-2 s-1) transpiration assimilation (C) (mg g-1 h -1) 2 2 0 0 12:00 00:00 00:00 12:00 00:00 06:00 18:00 06:00 18:00 local time [hh:mm] Challenges: Cloud cover, biomass burning, and lack of fundamental understanding of NMVOC emissions… TES data @ 6km, 11/04 O3 Improved cloud-clearing algorithms and better spatial resolution data help. CO A more integrated approach to understanding controls of NMVOCs, e.g., surface data, lab data, MODIS Firecount O3-CO-NO2-HCHO-firecount correlations import to utilize when looking at the tropics TES data c/o Bowman, JPL

  16. Some aerosol-climate effects SEVERI AOD N P D Z Africa South America CCN Primary and secondary aerosol sources: biomass burning, biogenic, desert dust Internally or externally mixed? visibility deposition Fe fertilization Ocean Ecosystem Africa

  17. “Expect harmful levels of ozone and PM2.5 over the next couple of days; please keep small children and animals inside. Transatlantic pollution represents 20% of today’s UK surface ozone.” 2010 O3 > 100 ppb on 6 consecutive days Estimated up to 700 extra deaths attributable to air pollution (O3 and PM10) in UK during this period 2pm, 6th Aug, 2003 “Normal” airmass flow 1400 40 35 1200 Isoprene (ppt) 30 Temperature (C) 1000 25 800 20 600 15 Stagnant airmass flow 400 10 200 5 0 0 4-Aug 2-Aug 6-Aug 8-Aug 27-Jul 29-Jul 31-Jul 12-Aug 16-Aug 10-Aug 14-Aug 18-Aug 20-Aug 22-Aug 24-Aug 26-Aug 28-Aug 30-Aug Compiled from UK ozone network data Isoprene c/o Ally Lewis

  18. GOME NO2 @ 1x1o NAEI NOX emissions as NO2, 2002 SCIA NO2 @ 0.4x0.4o, Aug 2004 Aug 1997 Edinburgh, 56N Length of day [hours] Cloud cover [%], ISCCP August 83-04 Denver, 40N Day of Year 70 100 30 Resolution of new satellite data allows study UK AQ from space OMI NO2 @ 0.1ox0.1o, Jul 2004 GOME and SCIA NO2 c/o R. Martin; OMI (unofficial) NO2 c/o T. Kurosu Challenges...

  19. BVOC fluxes for a “hot, sunny” day Monoterpenes Isoprene Stewart et al, 2003 The increasing role of BVOCs: constraints from OMI HCHO? OMI HCHO Data c/o T. Kurosu <0.3 2 1016 [molec cm-2]

  20. MISRSurface PM2.5 = ModelSurface [PM2.5] x MISR AOT Model AOT Space-based aerosol optical properties can help map emissions of particulate matter MISR AOT can help estimate total PM2.5: • Unclear what PM characteristics affect health • Secondary PM is formed from: • Oxidation of organic compounds • Oxidation of SO2 • Difficult to estimate offline – need models and data 2003 roadside (primary) PM10 Liu et al, 2004

  21. 5 5 4 4 3 3 2 2 Kahn, et al., JGR, submitted 1 10,000 0 5000 1 0.0 1.2 2.4 0.0 1.2 0.6 Case study of Oregon Fire using data from the Multi-angleImagingSpectroRadiometer (MISR) Plume Periphery: Higher AOT, Lower ANG, Lower SSA than Background Plume Core: Too Thick & Variable for Standard AOT Retrieval How do we optimally use this information operationally?

  22. 2) UKCA gas-aerosol chemistry scheme 1) UM mesoscale CTM AQ-climate links UKMO Unified Model Chem-Clim Model AQ Model Current Development in Modelling UK AQ • UK currently using MODELS 3 (MM5 + CMAQ) for AQ Global vs urban chemistry? Subgrid scale processes? • Similar equations for data assimilation and inverse modelling • J(x) = ½(yo – H(x))T(E+F)-1(yo-H(x)) +½(x-xb)TB-1(x-xb) • Multi-species analyses – inter-species error covariance? • Radiance versus retrieved products? • Limit of linearization of non-linear oxidant chemistry?

  23. TheOrbitingCarbonObservatory(OCO) “First global space-based measurements of CO2 with the precision and spatial resolution needed to quantify carbon sources and sinks” Launch in 2008 2-year mission • Spectroscopic observations of CO2 (1.61 m and 2.06 m) and O2(0.765 m)to estimate the column integrated CO2 dry air mole fraction, • XCO2= 0.2095 x (column CO2) / (column O2) • Precisions of 1 ppm on regional scales • Global coverage in 16 days (nadir 1x1.5 km footprint) • JPL-based instrument: PI D. Crisp; Deputy PI: C. Miller (Crisp et al, 2004)

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