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OMI follow-on Project Toekomstige missies gericht op troposfeer en klimaat Pieternel Levelt, KNMI.

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Presentation on theme: "OMI follow-on Project Toekomstige missies gericht op troposfeer en klimaat Pieternel Levelt, KNMI."— Presentation transcript:

1 OMI follow-on Project Toekomstige missies gericht op troposfeer en klimaat Pieternel Levelt, KNMI

2 Toekomstige Troposfeer Missie, SRON, 18 november 2003 Dr. P.F. Levelt (KNMI) Slide 2 Climate Air quality  Anthropogenic influence Importance of Tropospheric Measurements Tropospheric chemical science has very strong links to:

3 Toekomstige Troposfeer Missie, SRON, 18 november 2003 Dr. P.F. Levelt (KNMI) Slide 3 Troposphere Tropospheric measurements needs: higher spatial resolution improved accuracy for O 3, NO 2, aerosols, clouds, HCHO together with CO, CH 4, CO 2 and H 2 O improve aerosol information improve time-resolution preference for daily global coverage (air quality) GOME Observations of Formaldehyde over North America Chance et al., Geo. Res. Let. 27, , Next challenge for satellite instrument development is to map the troposphere for air quality monitoring and climate research:

4 Toekomstige Troposfeer Missie, SRON, 18 november 2003 Dr. P.F. Levelt (KNMI) Slide 4 Tropospheric Important Trace Species (tropospheric) Ozone Aerosols (tropospheric) NO 2 SO 2 Formaldehyde BrO UV/VIS CO CH 4 CO 2 H 2 O NIR

5 Toekomstige Troposfeer Missie, SRON, 18 november 2003 Dr. P.F. Levelt (KNMI) Slide 5 Why these trace species? CO indicates combustion; has a chemical role (CO 2, CH 4 ) HCHO indicates VOCs; has role in O 3 & aerosols NO 2 indicates NO x ; is precursor to O 3 & aerosols SO 2 traces combustion, is major aerosol precursor CO 2 is an important greenhouse gas H 2 O is an important greenhouse gas Ozone is a toxic greenhouse gas. Small aerosols are toxic, have direct & indirect global warming effects. I I I I

6 Toekomstige Troposfeer Missie, SRON, 18 november 2003 Dr. P.F. Levelt (KNMI) Slide 6 Climate Forcing Source: IPCC

7 Toekomstige Troposfeer Missie, SRON, 18 november 2003 Dr. P.F. Levelt (KNMI) Slide 7 Few measurements from space to date: except: MOPITT CO, TOMS residual O 3, GOME NO 2, BrO, HCHO, MODIS for aerosols and clouds TES and OMI (Aura) and SCIAMACHY (ENVISAT) will provide many new measurements Selected OCO NASA mission (2007): Measures CO 2 with 1 km 2 pixels and 10 km swath. However: Tropospheric chemical science needs more and more accurate measurements Currently available or selected tropospheric-climate missions

8 Toekomstige Troposfeer Missie, SRON, 18 november 2003 Dr. P.F. Levelt (KNMI) Slide 8 OMI on EOS Aura Spectrometer in wavelength range 270 – 500 nm Daily Global Coverage Small Ground Pixels (13x24 km 2 ) Polarization Scrambler

9 Toekomstige Troposfeer Missie, SRON, 18 november 2003 Dr. P.F. Levelt (KNMI) Slide 9 OMI Measurement Principle Courtesy of Dutch Space

10 Toekomstige Troposfeer Missie, SRON, 18 november 2003 Dr. P.F. Levelt (KNMI) Slide 10 New Developments for Polar missions Smaller Ground Pixels (will also improve accuracy) Extending the Wavelength Range (add IR-channel) Multi-Angle Viewing (for improved aerosol detection) Assumption: Start from current Leo-OMI optical design: This means that a smaller spatial resolution of 10 x 10 km 2 is not feasible, since this is the optical resolution of the instrument in polar orbit!

11 Toekomstige Troposfeer Missie, SRON, 18 november 2003 Dr. P.F. Levelt (KNMI) Slide 11 Chosen for a module approach: OMI/SCIAMACHY + instrument is by itself a very complete tropospheric instrument Depending on missions, channels can be adjusted or skipped

12 Toekomstige Troposfeer Missie, SRON, 18 november 2003 Dr. P.F. Levelt (KNMI) Slide 12 Requirements UV/VIS Ground pixels: decreased to 12 x 13 km 2 (except for UV-1, 40 x 40 km 2 ) Spatial sampling: 3 x nm, preferred extension to 600 nm (O 3 and O 2 -O 2 ) Spectral resolution: minimal OMI, preferred GOME Spectral sampling: 3 x Daily global coverage S/N ratios same as in OMI SRD, except for O 3 and NO 2 column

13 Toekomstige Troposfeer Missie, SRON, 18 november 2003 Dr. P.F. Levelt (KNMI) Slide 13 Requirements NIR Ground pixels: 12 x 13 km 2 Spatial sampling: 3 x 1,6 (CH 4 and CO 2 ) and 2,4 mm (CO) O 2 A band detection for airmass factor (760 nm) Spectral resolution: 0.08 nm (CO 2 ), 0.15 nm (CO & CH 4 ) and 0.08 nm for O 2 A band Spectral sampling: 3 x Daily global coverage for CO, for CH 4 and CO 2 not necessary (1000 km swath) S/N ratios: see input SRON

14 Toekomstige Troposfeer Missie, SRON, 18 november 2003 Dr. P.F. Levelt (KNMI) Slide 14 Technical Challenges Identified Size of instrument: - NIR increases size of instrument - High spectral resolution in combination with high spatial resolution and broad swath S/N: smaller pixels and same or increased S/N is needed ! CCD’s: CCD with preferred requirements at this moment non- existent; techniques to built it are however available Scrambler for polarisation insensitivity optimal for UV/VIS and IR Grating: New developed grating needed in order to decrease size of instrument Temperature control of instrument, especially 2,4 mm And more can follow ….. Caveat: in case higher spatial resolution is needed for tropospheric trace gases to obtain needed accuracy.

15 Toekomstige Troposfeer Missie, SRON, 18 november 2003 Dr. P.F. Levelt (KNMI) Slide 15 6 options UV/VIS and IR now studied by industry (1) Climate mission: Complete UV/VIS and CO, CO 2, CH 4 and O 2 A (2) Air Quality mission: Complete UV/VIS and CO (3) Climate mission with 1000 km swath for NIR and O 2 A (4) Climate mission as (1), without CO (5) Same as (3) but with 2 telescopes (6) Same as (1) but with 1000 km swath

16 Toekomstige Troposfeer Missie, SRON, 18 november 2003 Dr. P.F. Levelt (KNMI) Slide 16 Mean aerosol optical depth in August 1997 (monthly average). Retrieved from ATSR-2 image (see Gonzalez et al., Geophys. Res. Lett., 27, , 2000 ) Monitoring Aerosol

17 Toekomstige Troposfeer Missie, SRON, 18 november 2003 Dr. P.F. Levelt (KNMI) Slide 17 Aerosol retrieval Use dual viewing concept for info on surface albedo for aerosol retrieval and AMF information for trace gas retrieval - Current OMI for nadir - Add one viewing angle looking forward - Need for an extra CCD for forward looking channel, and second telescope Technical Challenge: calibration of those two channels with high accuracy! Not clear if this is feasible.

18 Toekomstige Troposfeer Missie, SRON, 18 november 2003 Dr. P.F. Levelt (KNMI) Slide 18 Summary OMI Technology is very suitable for remote sensing of the troposphere - Spatial resolution can be improved to 10 x 10 km 2 - Wavelength range can be extended to NIR High-level instrument requirements for UV/VIS and NIR are decided Currently 6 possible instrument designs are studied on feasibility: many technical challenges are identified Multi angle viewing seems to be more difficult than expected due to calibration difficulty Caveat: in case higher spatial resolution is needed: new instrument design probably needed


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