Longtime Satelite Observation of Atmospheric Trace Gases

Transcription

1 Longtime Satelite Observation of Atmospheric Trace Gases T. Wagner, S. Beirle, C. v. Friedeburg, M. Grzegorski, J. Hollwedel, S. Kühl, S. Kraus, W. Wilms-Grabe, M. Wenig, U. Platt Institut für Umweltphysik, University of Heidelberg, INF 229, D Heidelberg, Germany

2 Overview DOAS Analysis of GOME Data Tropospheric trace gases derived from GOME Satelite Data at the internet, TROPOSAT Cloud influence and -correction Outlook...SCIAMACHY

3 GOME (Global Ozone Monitoring Experiment) Launch: ERS-2, April 1995 GOME-Infos: DLR: ESA: Uni-Bremen: Uni-Heidelberg: Spectral resolution nm between 240 und 790 nm In addition to Ozone several other trace gases can be measured NO 2 BrO OClO HCHO, SO 2 H 2 O O 2 O 4

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5 VCD BrO, Earth s coverage by GOME VCD NO 2,

6 Atmospheric trace gas absorptions detected in satellite spectra O 4 O 3 UV OClO H 2 O HCHO O 2 Intensity [arbitrary units 1E+16 1E+14 1E+12 1E+10 1E+08 Satellite group: W avelength [nm ] SO 2 NO 2 BrO O 3 vis

7 Atmospheric Species measured by GOME & analysed at the University of Heidelberg OClO NO 2 BrO Stratosphere Satellite group: Troposphere n m ) NO 2 BrO HCHO SO 2 H 2 O O 4 / O 2

8 Tropospheric Satellite Data Products available via the TROPOSAT Web-Page PI Institution Species Details Initial contact John Burrows Andreas Richter IUP Bremen NO 2 BrO SO 2 HCHO O 3 tropical GOME Global and regional andreas.richter@iup.physik.uni-bremen.de web page: Rodolfo Guzzi ISAO-CNR, I aerosol GOME r.guzzi@isao.bo.cnr.it Hennie Kelder Henk Eskes KNMI, NL O 3 columns & profiles NO 2 GOME Global and regional O 3 in near real time eskes@knmi.nl web page: Gerrit de Leeuw TNO, NL aerosol unconfirmed various satellites, 2000 deleeuw@fel.tno.nl Martin Riese Uni-Wuppertal H 2 O (HNO 3 ) (CFC-11) CRISTA Nov. 1994, Aug upper-troposphere riese@wpos2.physik.uni-wuppertal.de

9 Tropospheric Satellite Data Products available via the TROPOSAT Web-Page PI Institution Species Details Initial contact M. van Roozendael BIRA-IASB, B NO 2 BrO GOME Global and regional michelv@oma.be Anne Thompson NASA (Goddard) O 3 TOMS (20oN to 20oS) NIMBUS 1979 to 1992 also SHADOZ 1998 to sonde profiles in the tropics thompson@gator1.gsfc.nasa.gov web page: metosrv2.umd.edu/~tropo SHADOZ: code916.gsfc.nasa.gov/data_services/shad oz Thomas Wagner Ulrich Platt Jerry Ziemke IUP, Heidelberg NASA Goddard NO 2 BrO SO 2 H 2 O HCHO GOME Global and regional O 3 Nimbus 7 Earth Probe TOMS (15oS-15oN) thomas.wagner@iup.uni-heidelberg.de web page: ziemke@jwocky.gsfc.nasa.gov web page: hyperion.gsfc.nasa.gov/data_services/clou d_slice/index.html

10 GOME Viewing Geometry

11 Dependence of the GOME measurements on the solar zenith angle SZA 12 albedo 0.8 albedo 0.0 geometric AMF AMF 8 4 stratospheric AMF 0 tropospheric AMF SZA [ ]

12 Stratospheric NO 2 Latitude Jan Apr Jul Oct Jan Apr Jul Oct Jan Apr Jul Oct Jan Apr Jul Oct Jan Apr Jul Oct stratospheric NO2 VCDs [1e15 molec./scm]

13 50 70 Shape of the polar vortex (35 PV units at 475K, ECMWF analysis) 90 SCD OClO [molec/cm²] 0 1.3e14 GOME OClO Observations Arctic winter 1997

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15 Tmin 475 K /96 OClOmax (90 SZA) Nov 26-Dec 25-Jan 24-Feb 25-Mar / T min (475K) [K] Nov 26-Dec 25-Jan 24-Feb 26-Mar Nov 26-Dec 25-Jan 24-Feb 26-Mar / / SCD OClO [1e14 molec/cm²] Nov 26-Dec 25-Jan 24-Feb 26-Mar / Nov 26-Dec 25-Jan 24-Feb 25-Mar / Nov 26-Dec 25-Jan 24-Feb 26-Mar / Nov 26-Dec 25-Jan 24-Feb 26-Mar Time 0

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17 NO2 VCD 9 days average clear sky minimum over 9 days NO2 VCDs [1e15 molec./scm]

18 NO2 VCD 9 days minimum (cloud free pixel) clear sky minimum over 9 days NO2 VCDs [1e15 molec./scm]

19 Selecting only measurements over the oceans filtered NO2 VCD pixels [1e15 molec./scm]

20 Interpolation and smoothing Stratospheric NO2 VCDs [1e15 molec./scm]

21 Difference between total VCD and stratospheric background => tropospheric NO2 Autumn 1997 tropospheric NO2 VCDs (uncorrected) [1e15 molec./scm]

22 Tropospheric NO2 after correction for different sensitivity to stratosphere and troposphere Autumn 1997 troposp. NO2 VCDs (albedo corrected) [1e15 molec./scm]

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24 NO 2 by lightning Lightning frequency compared to GOME-NO 2 * values for different months

25 Correlation of NO 2 * monthly means and Lightning activity 6 5 NO 2 * [10 14 molec/cm 2 ] Lightning Activity [Flashes/day/pixel]

26 NO 2 by biomass burning Annual biomass burning in south east Asia:

27 Fire counts Tropospheric NO 2 x10 15 molec/cm 2

28 Yearly cycle of NO 2, biomass burning and lightning in South East Asia for Fire counts [0.01/day/pixel] Lightning frequency [0.05/day/pixel] 15 NO 2 * [10 14 molec/cm 2 ] NO 2 * corr [10 14 molec/cm 2 ] Jun Dec Jun Dec Jun Dec

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30 The Sea-Ice Surface as a BrO Source in Polar Spring Northpole mean BrO VCDs 2000 Feb Mar Apr Southpole mean BrO VCDs 1999 May Aug Sep Oct Nov

31 GOME SO2 evaluation Nyamuragira Volcano, Orbit , , Lat.: -0.8, Long.: 26.8, SZA: Ring Optical density O3 SO Residual Wavelength [nm]

32 GOME SO

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34 VCD H2O [molec/cm²] 2.5E+23 2E E+23 1E+23 5E+22 Reih e1 GOME Reih ECMWF Latitude Figure 7: Latitudinal cross section of atmospheric water vapor measured by GOME. The data are compared to model results.

35 Information on cloud top height (and trace gas profile) is essential Nearly all GOME pixels (320 x 40 km²) are partly covered with clouds Clouds are typically much brighter than the cloud free scenes (except over ice and snow) Two dominant effects of clouds: A) Shielding effect for trace gases below clouds B) Albedo effect for trace gases above clouds (nearly no cloud effect for stratospheric trace gases)

36 Clouds, trace gas concentrations and surface properties can vary strongly accross one GOME ground pixel Minimum requirements: Cloud Fraction Cloud Top Height

37 Traditional Cloud algorithms for GOME Cloud fraction from the O 2 -A-band absorption (e.g. FRESCO, ICFA, etc..) Problems: Saturation, complicated radiative transport, interference with snow/ice Cloud fraction from High spatially resolved (20 x 40 km²) broad band spectral measurements (PMD) (e.g. CRAG, PCRA, OCRA, CRUSA, etc.) Problems: Interference with ice/snow

38 Existing cloud algorithms have problems over polar regions because of the high ground albedo CRUSA (Wenig, 2001) FRESCO (Koelemeijer et al., 2001)

39 Additional cloud sensitive parameters measured by GOME Cloud sensitive Parameter O 4 -absorption 630 nm O 4 -absorption 360 nm Colour Index Polarisation Ring effect O 2 -absorption 630 & 760 nm Depending on Clear view down to the ground Clear view down to the ground ground albedo Ratio of Rayleigh-scattered light to Mie-scattering and ground reflection Ratio of single Rayleigh scattered light to total intensity Ratio of Raman scattered light to total intensity Clear view down to the ground ground albedo

40 Absorption spectrum of the oxygen dimer O4 (Greenblatt et al., 1990). O 4 absorption bands analysed in GOME spectra O 4 -Absorptionen (Greenblatt et al., 1990) Wellenlänge [nm]

41 0.6 3 Test of different cloud sensitive parameters over extended clouds: : Hurricane Fran O2_630 OD_O2_761nm Polarisation_UV Polarisation_vis Polarisation_IR CI_UV CI_vis O4_360 O4_577 O4_ NOAA GOES-8 Satellite, 16:02 UTC 2 1 Ring_360 Ring_ Latitude

42 A Cloud product for Polar regions? O 4 and O 2 absorptions at 630 nm show different dependence on the cloud top height because of the different height profiles O 4 absorptions at different wavelengths (360 and 630 nm) show different dependence on the cloud top height because of the different strength of multiple scattering From the simultaneous observations of the O 4 bands at 360 and 630 nm as well as the O 2 band at 630 it should thus be possible to separate the effects of varying cloud fraction and cloud top height.

43 O 2 - and O 4 -absorptions in GOME spectra

44 O 4-AM F, 360nm SZA: 80, albedo: 80% 12 Modeling of the O 2 and O 4 absorptions as a function of the O nm Cloud top height cloud fraction (x-axis) and c le a r < Cloud fraction ----> cloudy O 4-AM F, 630nm SZA: 80, albedo: 80% 12 cloud top height (y-axis) O nm Cloud top height (radiative transport model AMFTRAN, Marquard et al., 2000) O nm C lear < C lo u d fra c tio n ----> clo u d y O 2 -AMF, 630nm SZA: 80, albedo: 80% cloud top height [km] clear < C lou d fractio n ----> cloudy

45 Coverage of the earths surface with ice and snow for April 1998 (Klimm, 2000)

46 Case Study Spitsbergen A B 03 Apr 1998 at IR satellite image ( µm). The red Rectangle indicates the location of the GOME center pixels of Orbit Arrows indicate the longitude of two selected observations. The images are obtained via the Dundee Satellite Receiving Station, Dundee University, Scotland (

47 5 4 O 4 and O 2 absorptions for the center pixel of GOME orbit The arrows mark the selected measurements. AMF AMF O4-AMF (360 nm) Longitude [ ] Reihe1 O4-AMF Reihe2 O4-AMF Max O2-AMF (630 nm) Longitude [ ] O2_AMF O2AMF_MAX AMF O4-AMF (630 nm) Longitude [ ] O4_AMF AMF_MAX

48 Cloud fraction and top height for case A Clear < Cloud fraction ----> cloudy Altitude [km]

49 Cloud fraction and top height for case B Altitude [km] Clear < Cloud fraction ----> cloudy 0

50 Conclusions & Future: Several Tropospheric data are already available (Several Groups and Instruments) More detailed cloud information is needed for the analysis of tropospheric data from space (Additional cloud sensitive parameters have to be used) Development of a new prototype cloud algorithm for polar regions using O 2 and O 4 absorptions Data from SCIAMACHY on ENVISAT

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