Post on 16-Jan-2016
Status of GEMS (Geostationary Envi-ronment Monitoring Spectrometer)
Mission
Jhoon Kim
P.I., GEMS Program
Director, Global Environment Satellite Research Center (GESC)
Professor, Department of Atmospheric Sciences,
Yonsei University, Seoul, Korea
(jkim2@yonsei.ac.kr)
GEOCAPE Community Workshop,
May 11th, 2011, Boulder, CO
ContributorsGEMS Science Team - KARI, Yonsei Univ., GIST, Pusan Nat’l Univ., SNU, Konkuk Univ., Ewha Women’s Univ.
H. Lee (Yonsei University)
Kelly Chance, Xiong Liu (Harvard Smithonian Center for Astro-physics)
GEMS SAG(Science Advisory Group) - NASA, GSFC, JPL, ESA, JAXA, NCAR, NRL, MPI, NOAA, KNMI, Harvard Univ., UCLA, Univ of Alabama, Dalhousie Univ., Univ of Iowa, Univ of Bremen, Univ of Heidelberg, Univ of Tokyo, …)
Ministry of Environment, Rep. of Korea
NIER(National Institute of Environmental Research)
1995~2006KOREASAT 1-5
National Space Program of Korea
1992-1999KITSAT-1~3
2003STSAT- 1
2006KOMPSAT-2
2011KOMPSAT-3
(EO)
1999KOMPSAT-1
2017KOMPSAT-7
(EO)
2011KOMPSAT-5
(SAR)
2010COMS
2015KOMPSAT-6
(SAR)
2009STSAT-2
2011STSAT-3
2012KOMPSAT-3A
(EO)
2009 KSLV-1
2008Astronaut
2017KSLV-II
2020Lunar Orbiter
2025Lunar Mission
2017
2010 KSLV-1
GEO
GEO
GEO
2011
2018 GEO KOMPSAT
2014CAS-12020
CAS-2
Restriction on Use, Publication, or Disclosure of Proprietary/Controlled Information – KARI proprietary
Political Support
GOCI-2Met.Payload
GEMS System/BusAIT
ME MEST
MLTMKMA
National Committee of Space Development
ME : Ministry of EnvironmentKMA : Korea Meteorological Administration
MEST : Ministry of Education, Science & TechnologyMLTM : Ministry of Land, Transport & Maritime Affairs
Collaborative Support from Govern-ment
GEO KOMPSAT
Spatial Coverage of GEMS
(Richter, 2005)
NS: 5 S ~ 55 N, EW: 75 E~145 E
GEOCAPE
Sentinel-4
GMAP-AsiaGEMS
POGEQA
Science Questions & Objectives of GEMSScience Questions Objectives
1. What are the temporal and spatial varia-tions of concentrations and emissions of gases and aerosols that are important for
air quality?
1. To provide measurements of atmospheric chemistry, precursors of aerosols and ozone in particular, in high temporal and spatial resolution over Asia
2. How do regional and intercontinental transport affect local and regional air quality?
2. To monitor regional transport events: transboundary pollution and Asian dust
3. How does air pollution drive climate forcing and how does climate change affect air quality?
3. To quantify radiative forcing of aerosol and ozone and to monitor air quality for long term
4. How does meteorology affect the air quality ?
4. To improve our understanding on interactions between atmospheric chemistry and
meteorology
5. Can we quantify the outflow from Asia to cross Pacific ?
5. To better understand the globalization of tropospheric pollution
6. How can we improve the accuracy of air quality forecast using satellite measurements?
6. To improve air quality forecast by constraining emission rates and assimilating chemical
observation data
Measurement of air quality in high temporal and spatial resolution
Credit: CCSP Strategic Plan (illustrated by P. Rekacewicz).
EMISSION(local and urban scale)
AIR QUALITY(local and regional)
LONG-RANGE TRANSPORT
METEOROLOGY
CLIMATE FORCING
Meteorology
Source Sink
FEEDBACK AtmosphericCorrection forOcean color
Information Service to Public
Air quality forecast with weather observation
PMAir quality
O3Air quality
Satellites
Surface monitors
CTM
Aircraft, lidar
NEW KNOWLEDGE
Air quality monitoring& forecasting
Source quantification,policing of environ-mental agreements
Long-range transport
Climate forcing
Biogeochemical cycling
Weather forecasting
NO2SO2O3
HCHOAerosolCloud
Data Assimilation
Integrated Simulation
Emission DB
CTM
Concentration, Ni (t, x,y,z)
RTM
GEMS Instrument
Function
GEMSRadiance SpectrumL (l; t, x,y)
Retrieval Algorithm
GEMS-retrieved
Concentration
N’i (t, x,y)
Surface Reflectance
a ( , , l q f; t, x,y)
Si (l; t, x,y)
Intercomparison
Ri ( )l
Met Field
Cloud, Wind, Vi (t, x,y,z)Temperature, T(t,x,y,z)…
Constrain / consistency?
GEMSInstrument Re-
quirements
Dynamic rangeSpectral rangeSpectral resolutionSNR, MTF …
Spectral coverage of GEMS
GEMS
AOD
0.1 1 10
Fre
qu
en
cy (
%)
01020304050
SO2 (1E+14 #/cm2)
0.1 1 10 100 1000
Fre
qu
en
cy (
%)
02468
101214
NO2 (1E+14 #/cm2)
0.1 1 10 100 1000
Fre
qu
en
cy (
%)
02468
101214
HCHO (1E+14 #/cm2)
0.1 1 10 100 1000
Fre
qu
en
cy (
%)
02468
101214
O3 (1E+16 #/cm2)
0.1 1 10 100 1000
Fre
qu
en
cy (
%)
02468
101214
Average probability distribution function (PDF)
Baseline products
Product Importance Min(cm-2)
Max(cm-2)
Nominal(cm-2)
Accuracy Spectral window
(nm)
Spatial Resolution
(km2)
SZA(deg)
NO2Ozone
precursor3x1013 1x1017 1x1014 1x1015 425 - 450 5 x 5 < 70
SO2Aerosol
precursor6x108 1x1017 6x1014 1x1016 310 – 330 5 x 5 < 60
HCHOProxy for
VOCs1x1015 3x1016 3x1015 1.0x1016 327 – 357 5 x 5 < 70
O3Oxidant, pollutant
4x1017 2x1018 1x1018 2% or 6 DU
300-340Chappuis
band ?5 x 5 < 70
AOD PM, type, 0 4 0.220% or 0.1@
400nm300-500 2.5 x 5 < 70
CHOCHO : Feasibility not confirmed yet
Radiance at GEMS
• Radiance for GEMS: libRadtran SZA:0-70o
Surface albedo 0.03 (Lambertian Surface) Gases: O3, SO2, HCHO, NO2 + Aerosol
• Min. Clear sky condition based on CMAQ v4.5.1 • GEMS’s solid angle: 5×5 km 1.9×10-8 sr • 0.2 nm sample, 0.6 nm resolution (FWHM) for
GEMS
Radiance at GEMS
Maximum gas column densities and AOD (BC) with the highest PDF value
Minimum gas column densities and AOD (Sulfate) with the highest PDF value
Nominal gas column densities and minimum AOD (Sulfate)
Min. Radiance
Max. Radiance
70605040302010
0
Molecules Wave-length window
(nm)
Radiance Time # of pho-tons cm-2
px-1
SO2 & O3 315-335 1.25×1012 6 2.91×104
HCHO 327-356 3.23×1012 6 7.49×104
NO2 423-451 5.42×1012 2 4.18×104
Min. & Max. radiance at GEMSA. Minimum radiance obtained frommaximum gas column densities and AOD (BC) with the highest PDF value
B. Maximum radiance obtained from minimum gas column densities and AOD (Sulfate) with the highest PDF value
Molecules Wave-length window
(nm)
Radiance Time # of pho-tons cm-2
px-1
SO2 & O3 315-335 2.17×1013 6 5.03×105
HCHO 327-356 2.19×1013 6 5.09×105
NO2 423-451 3.02×1013 2 2.33×105
Mole-cules
Wave-length window
(nm)
RadianceRange
Time # of photon cm-2 px-1
SO2 & O3 315-335 2.41×1012 - 1.98×1013 6 5.58×104 –
4.59×105
HCHO 327-356 6.11×1012 - 2.08×1013 6 1.41×105 –
4.83×105
NO2 423-451 9.09×1012 - 2.74×1013 2
7.02×104 – 2.11×105
C. Radiance obtained from nominal gas column densities and minimum AOD (Sulfate)
Cloud
17
Radiance simulation for GEMS
(K.M. Lee)
The percentage of clear sky region
Resolution March June September December
4kmⅹ4km 38.15 30.82 33.80 37.68
8kmⅹ8km 24.05(33.17)
19.25(26.62)
21.86(29.57)
23.06(32.36)
16kmⅹ16km 13.66(27.13)
10.80(21.70)
12.81(24.54)
12.90(25.96)
1 In terms of area at a given time2 The ratios in parentheses are the value when allowing 25% cloud fraction for clear sky region.
18
(Y.S. Choi and J. Kim)
19
0.2 nm: original model spectra resolution0.4, 0.6, and 0.8 nm: Virtual instrumental spectra resolution
Solar ZA:60Solar AA:300Satellite ZA:30Satellite AA:300
Case 1: spectrum for analysis (NO2) _ (420-450nm)
(Y.J. Kim)
Case 1: Result of NO2 SCD
20
Instrument spec-tral
resolution(nm)
NO2 SCD(molecules/
cm2)
Rela-tive Er-ror(%)
NO2 SCD Fitting error(molecules/
cm2)
Relative fit-ting
error (%)
Minimum detectable
SCD (2σ)(molecules/
cm2)
Usefulness
0.2 2.86E+17 1.06E+16 3.7% 2.11E+16 o
0.4 2.82E+17 -2% 1.53E+16 5.4% 3.06E+16 o
0.6 2.74E+17 -4% 1.22E+16 4.4% 2.44E+16 o
0.8 2.65E+17 -7% 1.23E+16 4.6% 2.46E+16 o
(Y.J. Kim)
21
± 3.7%± 5.4% ± 4.4% ± 4.6%
Case 1: NO2 slant column density and Uncertainty
(fitting interval: 430-450 nm)
± 10.0% rela-tive error
(Y.J. Kim)
Case 2: Result of SO2 SCD
22
Instrumentspectral
Resolution (nm)
SO2 SCD(molecules/
cm2)
RelativeError (%)
SO2 SCDfitting error(molecules/
cm2)
Relative fitting Error (%)
Minimumdetectable
SCD(2σ)
Useful-ness
0.2 (310-330 nm) 3.99E+16 1.37E+15 3.4% 4.10E+15 O
0.4 (310-330 nm) 3.55E+16 -11% 1.82E+15 5.1% 5.47E+15 Δ
0.6 (310-330 nm) 1.96E+16 -51% 2.54E+15 12.9% 7.61E+15 ?
0.8 (310-330 nm) 1.25E+16 -69% 3.19E+15 25.6% 9.58E+15 X
(Y.J. Kim)
23
Case 2: SO2 slant column density and Uncertainty
(fitting interval: 310-330 nm)
± 3.4%
± 5.1%
± 12.9%
± 25.6%
± 20.0% relative error
(Y.J. Kim)
24
Retrieved O3 and its % errors
(%
)
(#
/cm
2)
Retrieved O3 Column concentration
Relative Error
Spectral resolution (nm)(R. Park)
25
Retrieved HCHO and its % errors
(#
/cm
2)
(%
)
Retrieved HCHO Column concentration
Relative Error
Spectral resolution (nm) (R. Park)
(K. Chance)
(K. Chance)
(K. Chance)
(K. Chance)
SNR Requirements
Wavelengths (nm)
SNR Related gas
Remark
315-325 1225 SO2
327-356 1394 HCHO
423-451 1800 NO2
433-465 1931 CHOCHO
• For 8x8 km2 footprints• May consider spatial coadding
GEMS Requirements
System Attributes Requirements
Lifetime> 7 years
[option : >10 years]
Reliability > 0.85 @EOL
Field of regard5000 km (N/S) 5000 km (E/W)
[Region of interest : 55N~5S, 75E~145E]
Duty cycle / Imaging time8 images during daytime
(30 min imaging + 30 min rest) 8 times / day
Ground sampling distance
< 5 km (N/S) 5 km (E/W) for gases at Seoul
[option : < 2.5 km (N/S) 7.5 km (E/W)]
2.5 km (N/S) x 5 km (E/W) for aerosol
Spectral range 300 nm to 500 nm [Option: 300 to 650 nm]
Spectral resolution < 0.6 nm
Spectral sampling < 0.2 nm (3 samples)
Signal-to-noise ratio> 720 @nominal radiance of 320nm (TBC)
> 1500 @nominal radiance of 430nm (TBC)
Data quantization 12 bits
31
GEMS Requirements
System Attributes Requirements
MTF> 0.3 in N/S direction @Nyquist frequency
> 0.3 in E/W direction @Nyquist frequency
Radiometric calibration accu-
racy< 4%
Spectral calibration accuracy < 0.02 nm
Polarization factor < 4% (TBC)
Polarization factor variance < 1%
Data rate < 10 Mbps (Option: 40 Mbps)
Mass < 110 Kg
Volume < 800 mm x 1200 mm x 700 mm
32
Heavy shielding could effectively protect the primary particles at the expense of mass and volumeAs the incident energy increases, more thicker shielding is required.
Relation between the incident energy and shielding thickness is not linear for aluminum shielding.
10 kg of Al shield was adopted in OMI whose total mass is 65 kg.
33
Space radiation
Proton propagation in Al Al Shield Thickness vs. Proton Energy
De-polarizer : use to minimize polarization effect
Major source of polarization : grating or prism
De-polarization methodSpatial averaging – employing birefringent crystal wedge devices (OMI case)– Usually used in LEO or in case of low spatial resolution (induce image degradation)
Spectral averaging – the basis of the Lyot depolarizer– In case of low spectral resolution (induce spectral degradation)
Temporal averaging – Time-Domain Polarization Scrambler (TDPS)– Use the photo-elastic modulator, now under development, No spatial/spectral degradation
SolutionFirst of all, the polarization sensitivity of optical system shall be minimized.
TDPS is best if possible, Lyot depolarizer is also suitable for GEO.
34
Polarization
Double Wedge Scrambler Lyot Polarization Scrambler TDPS test setup
GEMS Interface RequirementInterface Requirements - Volume < 800mm(XSAT) 1200mm(YSAT)
700mm(ZSAT)
- Mass < 110 kg
GEO KOMPSAT Configuration
GEMS and GOCI-2 may have more volume and mass budget
- Can increase capability in spatial resolutionor spectral coverage
Mission : Air Pollution Monitoring Meteorological observation Ocean Color monitoring
Mass : Dry mass 1280.9 kg Launch mass 2640 kg
Power : In-orbit 1500 W, Transfer orbit 1100 WMission Life : 10 years
2A Sat. : Met Sensor 2B Sat. : GEMS,
GOCI-2
(Twin Satellites)
2A 2B
Satellite configuratio
n w/payloads
Resolution• 16 ch, Full size image < 15 min• 0.5, 1 km (Vis), 2 km (IR)
• GOCI-2 : 250 m• GEMS : 5 km x 5 km
Life time 10 years 10 years
Launch Mass
2849 kg 2550 kg
Power 2903 W 2903 W
Orbit GEO @ 128.2±0.05 E GEO @ 128.2±0.05 E
Solar Panel
ABI
GOCI-2
Solar Panel
GEMS
Status of GEO KOMPSAT Mission• GEMS Program Office
– Established GEMS Program Office inside ME and GEMS Research Center at Yonsei Univer-sity in 2009
– Started preliminary study in 2009 to setup requirements and instrument concept design by ME
• Budget– Following the successful launch of COMS in June, 2010, the budget request proposal was approved on Dec. 2010 by the Government Budget Review Committee led by the Ministry of Planning and Finance.
• RFP– Response to RFI received in Dec. 2010– RFP planned to be issued in the fall, 2011 – Selection of main contractor by the end of 2011
• International Collaboration– Recognized as a part of ACC by CEOS– Established Technical Group on Atmospheric Composition Measurements from Geostationary
Satellites with NASA– ToR for NASA-NIER/ME collaboration endorsed by NASA HQ and NIER/ME– MOU with NCAR(2010) and Harvard CfA (2011, ongoing)– Collaboration under discussion with Netherland and Japan
Master Schedule of MP-GEO SAT
Global Environmental Monitoring
Constellation of GEO Mission to study Air QualityConstellation of GEO Mission to study Air Quality
GEO-CAPE(America)
GMES S4MTG (Europe)
GEMSGEO KOMPSAT(Asia)
Constellation synergy- Improving spatial and temporal coverage to monitor globalized pollutants- Sharing basic requirements on data products and instrument to maintain data quality- Consolidating socio-economic benefit analysis- Supporting QA and CAL/VAL
GMAP Asia(Asia Pacific)
POGEQA(Europe)
ChineseGEO AQ Mission(Asia)
THANK YOU FOR YOUR ATTENTION !
40
Status of GEMS (Geostationary Environment Monitoring Spec-
trometer)
Jhoon Kim
P.I., GEMS Program
Director, Global Environment Satellite Research Center (GESC)
Professor, Department of Atmospheric Sciences,
Yonsei University, Seoul, Korea (jkim2@yonsei.ac.kr)
GEOCAPE Community Workshop, May 11th, 2011, Boulder, CO