Trace Gas Performance of Sentinel 4 UVN on Meteosat Third Generation

Transcription

1 Trace Gas Performance of Sentinel 4 UVN on Meteosat Third Generation Heinrich Bovensmann, S. Noël, K. Bramstedt, P. Liebing, A. Richter, V. Rozanov, M. Vountas, J. P. Burrows University of Bremen, Germany Acknowledgments to ESA and EUMETSAT colleagues: J. Langen, E. Brinksma, B. Veihelmann, G. Bazalgette Courrèges-Lacoste, J.L. Bezy, R. Stuhlmann, S. Tjemkes

2 UVN Geostationary chemistry observations: GMES Sentinel-4 UVN Sentinel 4 geostationary atmospheric UVN Mass Limit: 140 kg composition mission Applications: monitoring changes in the atmospheric composition, e.g. ozone, NO 2, SO 2, formaldehyde, glyoxal (VOC) and aerosol, at high temporal and spatial resolution Synergy with imager (clouds, aerosol), LI and IRS (O 3, CO) Imaging spectrometer covering UV ( nm), visible ( nm) and near-ir ( nm) bands, spectral resolution 0.5 nm (NIR 0.06 nm) Spatial sampling 5 km SSP Temporal sampling: hourly Geostationary orbit, at 0 o longitude Coverage: Europe and surroundings Embarked on MTG-S (launch 2017) and operated by EUMETSAT, Mission duration 2 x 7 years

3 Overview Objective: perform sensitivity studies in support of ESA s Sentinel 4 UVN development program to link sensor requirements and parameters to Level 2 data quality Approach: forward model simulating the radiances, incl. polarisation instrument and calibration model simulates the measured irradiance and radiance taking into account sensor characteristics from /MRD 2008/ and updates by ESA. optimal estimation retrieval scheme to derive error of the relevant geophysical parameters (total and tropospheric columns) from the simulated TOA reflectance Compare simulated errors with specified L2 performance MRD 2008

4 Geographical Coverage & Fachbereich Sampling 1 Institut für Umweltphysik/Fernerkundung 6O 4O 2O 3O W O 3O E Coverage: Focus on European users (GMES) Nominal: Longitude: 30 W N Latitude: 30 N - 65 N Movable in NS by 10 Temporal & Spatial Sampling: < 60 min. 8 km x 8 45 N

5 Key Requirements S4/5 Mission Requirements Document Issue 2 Spectral: nm with 0.5 nm spectral resolution nm with nm spectral resolution (new goal: 0.12 nm) SNR Reference Scenario: 50 N, 15:00 UTC, Equinox, albedo 0.05 (UV- VIS) 0.15 (NIR) UV: VIS/NIR: 1400 Radiometric Accuracy Absolute: 2-3% Relative spectral: 0.05%

6 Sensitivity Study Concept

7 Scenario Definition (MRD) Parameter Value L min L ref L max Location 61N, 0E 50N, 0E 30N, 0E Time 16:30 UTC 15:00 UTC 12:00 UTC Date 21 September 21 September 21 June Sub-satellite position 0N, 0E 0N, 0E 0N, 0E Surface Albedo UV 5% 5% 110% VIS 5% 5% 110% NIR 15% 15% 110% Atmospheric Profile US Standard 1976 US Standard 1976 US Standard 1976 Background aerosol Background aerosol Background aerosol No cloud sor precipitation No cloud sor precipitation No cloud sor precipitation Geometry L ref : Instrument position: 0ºN, 0ºE, km Observed point: 50ºN, 0ºE Fall equinox (22 Sep.), satellite: SZA 45.0º, rel SAA 90.0º ground: SZA 64.0º, rel SAA º LOS (versus nadir) 7.31º

8 Scenario Baseline Background Moderate Polluted Polluted Gas [mol/cm2] [mol/cm2] [mol/cm2] O3 6,4E17 1.4E18 2.8E18 NO2 3.9E14 5.4E15 1.0E16 SO2 2.7E15 3.1E16 9.1E16 HCHO 1.6E15 7.9E15 3.0E16 SC1 SC2 Season Fall/Winter Boundary layer aerosol type Urban Boundary layer visibility 10 km Boundary layer humidity 80% Tropospheric visibility 23 km Tropospheric humidity 80% Stratospheric aerosol loading Background Stratospheric aerosol type Background Mesospheric aerosol loading Normal mesosphere

9 Typical distributions of trace Fachbereich gases 1 Institut für Umweltphysik/Fernerkundung CHIMERE vs. SCIAMACHY HCHO [Dufour et al. 2008]

10 Scenarios atmosphere Scenario 01 polluted with background ozone trace gas columns: total troposh. HCHO 3.10e e16 SO2 9.18e e16 NO2 1.58e e16 O3 9.19e e18 Albedo UV/vis: 0.05 NIR: 0.15 p,t US-standard background aerosol (LOWTRAN) Scenario 02 moderate polluted atmosphere trace gas columns: Albedo UV/vis: 0.05 NIR: 0.15 total p,t US-standard background aerosol (LOWTRAN) troposph. HCHO 0.82e e16 SO2 3.14e e16 NO2 1.07e e16 O3 10.0e e18

11 Settings forward and retrieval Fachbereich model 1 Institut für Umweltphysik/Fernerkundung UV-VIS nm nm, trace gases: O 3,NO 2, SO 2, BrO, NO 3, HCHO, O 4 NIR nm nm, trace gases: O 2, O 3, H 2 O Fitting windows O 3 : nm NO 2 : nm SO 2 : nm HCHO : nm Aerosol Vertical optical depth at 412 nm, 486 nm, 755 nm

12 Instrument / Error model settings -1- Institut für Umweltphysik/Fernerkundung MRD-Run Concept_June09 band spectr. range [nm] spectral resolutio n [nm] spectr al sampling band spectr. range [nm] spectral resolutio n [nm] spectr al sampling ~ ~ ~3 scalar parameter error model spectral shift (Err 02) 0.02 SSI spectral stability (Err 03) 0.05 SSI knowledge of spectral slit function (Err 04) 0.01

13 Instrument / Error model settings -2- Institut für Umweltphysik/Fernerkundung Concept_June09 : Signal to Noise (Err 01) MRD-Run: Signal to Noise (Err 01)

14 Instrument / Error model settings -3- Institut für Umweltphysik/Fernerkundung MRD-Run Concept_June09 Err 05: absolute radiometric acc. radiance: 3% Err 06: relative spatial radiometric acc: 0.25% Err 08: absolute radiometric acc. irradiance: -3% Slit function: Gaussian slit function with FWHM of spectral resolution (04: 1% err on FWHM) Slit function ISRF for 3-4 wave-length per band (04: 1% err on FWHM)

15 Summary tropospheric column Scen. 01 Institut für Umweltphysik/Fernerkundung (polluted atmosphere with backgrounnd ozone) - systematic error is the quadratic sum of the individual errors MRD-Run Concept_June09 stat.err syst.err stat.err syst.err HCHO 22.76% 5.18% 16.86% 6.73% SO2 7.35% 13.74% 5.42% 12.19% NO % 3.93% 8.60% 2.39% O3 3.47% 1.52% 3.21% 1.72% Sensor Concept June 2009 has reduced statistical error because of improved signal to noise compared to MRD. SO2 systematic error is dominated by the spectral stability Aerosol VOD error is dominated by radiometric calibration

16 Summary Reference Concept June 2009 leads to decreased statistical error compared to MRD concept due to improved signal to noise. Reference Concept June 2009 (tropospheric columns): HCHO / SO2 events are detectable with an instrument error of ~20% / ~14% moderate HCHO / SO2 loading is (almost) undetectable High NO 2 values have a total error of ~9%, moderate ~17%. Background O3 is detectable within ~4%. Aerosol VOD at 412nm / 486nm / 755nm has an error of ~8% / 5 % / 4%, dominated by radiometric knowledge. Reminder: These are the sensor related errors!

17 Outlook Study continues until early 2010 focusing on: Building up a full error budget incl. scene related errors Investigate O2 A-Band high spectral resolution for AOD(z) Investigation spectral calibration, polarisation, co-registration etc. Perform simulations for Phase A Sensor Baseline

18 S4 UVN Synergies on MTG for Fachbereich Tropospheric 1 Chemistry and Air Pollution Applications Institut für Umweltphysik/Fernerkundung MTG-IRS S4-UVN on MTG MTG-FCI O 3, CO, NO 2, SO 2, VOC(H 2 CO, CHOCHO), AAI, Aerosol/PM MTG-IRS, MTG-UVS/S4 UVN, and MTG-FDCI/LI will provide unique and relevant data for tropospheric monitoring applications

19 Perspective GeoCAPE Sentinel 4 GeoASIA + LEO for the global context

20 Join COSPAR 2010 in Bremen! Institut für Umweltphysik/Fernerkundung

21 Level 2 requirements (MRD) Institut für Umweltphysik/Fernerkundung B1 / B2 Theme: Category: Air Quality Protocol Monitoring & NRT Requirement Data Product Driver Height Range Horizontal resolution (km) Vertical resolution (km) Revisit Time (hours) Uncertainty O 3 Interpolation of Surface network; Boundary condition; UV actinic fluxes PBL FT Trop. Column Total Column 5 / / / 3 24 / 24*3 10% 20% 25% 3%, (5% NRT) NO 2 Interpolation of Surface network; Emissions; Boundary condition PBL FT Trop. Column Total Column 5 / 50 1 / 3 10% 20% 1.3e 15 molec/cm 2 1.3e 15 molec/cm 2 SO 2 Interpolation of Surface network; Emissions; Boundary condition PBL FT Trop. Column Total Column 5 / 50 1 / 3 20% 20% 1.3e 15 molec/cm 2 1.3e 15 molec/cm 2 CH 2O Interpolation of Surface network; VOC Emissions; Boundary condition PBL FT Trop. Column Total Column 5 / 50 1 / 3 20% 20% 1.3e 15 molec/cm 2 1.3e 15 molec/cm 2 Aerosol OD Interpolation of Surface network; Emissions; Boundary condition; UV actinic fluxes PBL FT Trop. Column Total Column 5 /