Detection of aerosols and other climatological effects by remote
Document Sample
Detection of
aerosols and other
climatological
effects by remote Detection of aerosols and other
sensing using
GERB/SEVIRI climatological effects by remote sensing
Stijn Nevens
using GERB/SEVIRI
Introduction
GERB
Aerosol Detection Stijn Nevens, Edward Baudrez, Nicolas Clerbaux, Ilse
Aerosol Radiative
Forcing
Decoster, Steven Dewitte, Alessandro Ipe, Almudena
Conclusions
Velazquez
Royal Meteorological Institute of Belgium (RMIB)
Climate Monitoring SAF (CM-SAF)
Geostationary Earth Radiation Budget Team (GERB)
ESSC Remote Sensing workshop, VUB (Brussels)
2010/11/25
Outline
Detection of
aerosols and other
climatological Introduction
effects by remote
sensing using
GERB/SEVIRI
GERB
Instrument
Stijn Nevens
Products
Introduction
Aerosol Detection
GERB
Motivation
Aerosol Detection
Algorithm Presentation
Aerosol Radiative
Forcing Ocean Reflectance
Conclusions Land Minimum Reflectance
AOD Retrieval
Validation
Examples
Aerosol Radiative Forcing
Conclusions
Outline
Detection of
aerosols and other
climatological Introduction
effects by remote
sensing using
GERB/SEVIRI
GERB
Instrument
Stijn Nevens
Products
Introduction
Aerosol Detection
GERB
Motivation
Aerosol Detection
Algorithm Presentation
Aerosol Radiative
Forcing Ocean Reflectance
Conclusions Land Minimum Reflectance
AOD Retrieval
Validation
Examples
Aerosol Radiative Forcing
Conclusions
Earth Radiation Budget
Detection of
aerosols and other
climatological
effects by remote
sensing using
GERB/SEVIRI
Stijn Nevens
Introduction
GERB
Aerosol Detection
Aerosol Radiative
Forcing
Conclusions
Main interest GERB team at RMIB.
Outline
Detection of
aerosols and other
climatological Introduction
effects by remote
sensing using
GERB/SEVIRI
GERB
Instrument
Stijn Nevens
Products
Introduction
Aerosol Detection
GERB
Instrument Motivation
Products
Algorithm Presentation
Aerosol Detection
Ocean Reflectance
Aerosol Radiative
Forcing
Land Minimum Reflectance
Conclusions
AOD Retrieval
Validation
Examples
Aerosol Radiative Forcing
Conclusions
SERVIRI
Detection of
aerosols and other
climatological
effects by remote
sensing using
GERB/SEVIRI Spinning Enhanced Visible and
Stijn Nevens Infrared Imager.
Introduction Main instrument aboard MSG
GERB satellite (2004-. . . ).
Instrument
Products Spectral properties:
Aerosol Detection 12 narrow-band channels
Aerosol Radiative → chosen for specific detection
Forcing
purposes.
Conclusions
Temporal resolution: 15 minutes interval
Spatial resolution: 3km×3km at nadir (1km HRVIS)
GERB
Detection of
aerosols and other
climatological
effects by remote
sensing using Geostationary Earth Radiation Budget instrument.
GERB/SEVIRI
Announcement of opportunity instrument on MSG.
Stijn Nevens
Introduction
Spectral properties:
GERB 2 broad-band channels
Instrument
Products
Short wave: 0.32- 4 µm
Aerosol Detection
→ solar channel
Aerosol Radiative
Total: 4 - 30 µm
Forcing Longwave: by subtraction
Conclusions → thermal channel
Temporal resolution: 15 minutes interval
Spatial resolution: 44.5km×39.3km at nadir (NS x EW)
→ Upsampling using SEVIRI: 9km×9km
GERB High Resolution Example
Detection of Reflected solar radiation.
aerosols and other
climatological
effects by remote
sensing using
GERB/SEVIRI
Stijn Nevens
Introduction
GERB
Instrument
Products
Aerosol Detection 20070809 07:15 20070809 14:15
Aerosol Radiative
Forcing
Conclusions
Emitted thermal radiation.
Top Of Atmosphere Products (TOA)
Detection of
aerosols and other
climatological
effects by remote
sensing using
GERB/SEVIRI
We provide three TOA products (CM-SAF) form 2004
Stijn Nevens on:
Introduction Total Incoming Solar radiation (TIS).
GERB
Total Reflected Solar radiation (TRS).
Instrument Total Emitted Thermal radiation (TET).
Products
Aerosol Detection Daily mean, monthly mean diurnal cycle and monthly
Aerosol Radiative mean.
Forcing
Conclusions
To get these (and much more):
http://www.cmsaf.eu
http://cmsaf.oma.be
Total Incoming Solar Radiation (TIS)
Detection of
aerosols and other Computed from TSI (Total Solar Irradiance)
climatological
effects by remote
sensing using
GERB/SEVIRI
TIS cos(θsol )
TSI =
Stijn Nevens d2
Introduction where,
GERB d = distance pixel sun (astronomical units).
Instrument
Products
θsol = solar zenith angle
Aerosol Detection TSI measured over 3 decades:
Aerosol Radiative
Forcing
Conclusions
Example TIS
Detection of
aerosols and other
climatological
effects by remote
sensing using
GERB/SEVIRI
Stijn Nevens
Introduction
GERB
Instrument
Products
Aerosol Detection
Aerosol Radiative
Forcing
Conclusions
TRS and TET
Detection of
aerosols and other
climatological
effects by remote
sensing using
GERB/SEVIRI
Obtained from GERB instrument
Stijn Nevens
GERB field of view.
Introduction ADM to correct for angles.
GERB Spatial upsampling.
Instrument
Products + CERES experiment → polar region.
Aerosol Detection
+ SEVIRI
Aerosol Radiative
Forcing If no GERB data available.
Conclusions
→ narrow to broadband conversion: GERB-like data.
The future: no GERB instument on MTG.
And the past: no GERB instument on MFG.
Example TRS
Detection of
aerosols and other
climatological
effects by remote
sensing using
GERB/SEVIRI
Stijn Nevens
Introduction
GERB
Instrument
Products
Aerosol Detection
Aerosol Radiative
Forcing
Conclusions
Example TET
Detection of
aerosols and other
climatological
effects by remote
sensing using
GERB/SEVIRI
Stijn Nevens
Introduction
GERB
Instrument
Products
Aerosol Detection
Aerosol Radiative
Forcing
Conclusions
Example with Netto Irradiance at TOA
Detection of
aerosols and other
climatological
effects by remote
sensing using
GERB/SEVIRI
Stijn Nevens
Introduction
GERB
Instrument
Products
Aerosol Detection
Aerosol Radiative
Forcing
Conclusions
Outline
Detection of
aerosols and other
climatological Introduction
effects by remote
sensing using
GERB/SEVIRI
GERB
Instrument
Stijn Nevens
Products
Introduction
Aerosol Detection
GERB
Motivation
Aerosol Detection
Motivation Algorithm Presentation
Algorithm
Presentation Ocean Reflectance
Ocean Reflectance
Land Minimum
Land Minimum Reflectance
Reflectance
AOD Retrieval
AOD Retrieval
Validation
Examples
Validation
Aerosol Radiative
Examples
Forcing
Conclusions
Aerosol Radiative Forcing
Conclusions
Motivation
Detection of
aerosols and other
climatological
effects by remote
sensing using
GERB/SEVIRI Tropospheric aerosol particles originate from:
Stijn Nevens Urban/industrial activities.
Introduction Biomass burning associated with land use processes.
GERB
Wind-blown dust.
Aerosol Detection
Motivation Natural sources.
Algorithm
Presentation
Ocean Reflectance Global observations from space required due to:
Land Minimum
Reflectance
AOD Retrieval
Short lifetime (a few days).
Validation
Examples High spatial variability in aerosol optical and radiative
Aerosol Radiative
Forcing
properties.
Conclusions
Motivation (bis)
Detection of
aerosols and other
Major uncertainty in predicting climate change due to:
climatological
effects by remote
Direct radiative forcing → radiation is scattered or
sensing using
GERB/SEVIRI
absorbed by the aerosols.
Stijn Nevens
Indirect radiative forcing → influence on cloud
microphysics.
Introduction
Modify concentration of climate-influencing
GERB
constituents such as greenhouse gases trough
Aerosol Detection
Motivation heterogeneous chemistry.
Algorithm
Presentation
Ocean Reflectance
Land Minimum
Reflectance
AOD Retrieval
Validation
Examples
Aerosol Radiative
Forcing
Conclusions
Input
Detection of
aerosols and other
climatological
effects by remote
sensing using
GERB/SEVIRI
Stijn Nevens
Introduction
SEVIRI level 1.5 images at wavelengths 600, 800 and
GERB
1600 nm.
Aerosol Detection CM SAF cloud mask, based on NWC SAF software.
Motivation
Algorithm
Presentation
← planned replacement for current inadequate cloudmask.
Ocean Reflectance
Land Minimum
Reflectance
Cloud shadows also need to be implemented.
AOD Retrieval
Validation
Examples
Aerosol Radiative
Forcing
Conclusions
Reflectance (Rescaled BRDF)
Detection of
aerosols and other
climatological
effects by remote
sensing using
Single scatter approximation → separation
GERB/SEVIRI
Stijn Nevens R(λ, µi , µo ) = Rsurface + Rrayleigh + Raerosol
Introduction
The aerosol reflectance is given by,
GERB
Aerosol Detection ˜
τ ω P(θ)
Motivation Raerosol =
Algorithm
Presentation
4 cos(ωi ) cos(ωo )
Ocean Reflectance
Land Minimum
Reflectance where,
AOD Retrieval
Validation τ = aerosol optical depth (AOD).
Examples
Aerosol Radiative
˜
ω = aerosol single scatter albedo.
Forcing P(θ) = aerosol phase function.
Conclusions
Rrayleigh is calculated using RTE.
Ocean Reflectance
Detection of
aerosols and other
climatological
effects by remote
sensing using
GERB/SEVIRI
Stijn Nevens
Rsurface ← a fixed value chosen according to statistics
Introduction on marine reflectance synthesis.
GERB
→ works far away from sun glint region, where:
Aerosol Detection
Motivation
Rsurface peaks.
Algorithm
Presentation
Depends on wind speed.
Ocean Reflectance
Land Minimum
Reflectance
Upgrade to LUT from Cox-Munk surface model
AOD Retrieval
Validation
planned.
Examples
Aerosol Radiative
Forcing
Conclusions
Land Minimum Reflectance
Detection of
aerosols and other
climatological
effects by remote
sensing using
GERB/SEVIRI
Rsurface calculated assuming
Stijn Nevens Rsurface constant over sufficiently long period (15d).
Introduction
τ (AOD) reaches its background value in this period.
GERB R(λ = 600nm) increases with increasing AOD.
Aerosol Detection
Motivation
→ only true when Rsurface is small (dark surface).
Algorithm
Presentation Background aerosol day = day in the period under
Ocean Reflectance
Land Minimum
Reflectance
consideration when
AOD Retrieval
Validation
Examples R(λ = 600nm) − Rrayleigh (λ = 600nm)
Aerosol Radiative
Forcing
reaches its minimum.
Conclusions
Land Minimum Reflectance (bis)
Detection of
aerosols and other
climatological
effects by remote
sensing using
GERB/SEVIRI
Stijn Nevens The surface reflectance (for all λ) is then given by:
Introduction ˜ ˜ ˜
Rsurface = R − Rrayleigh − Raerosol
GERB
Aerosol Detection
Motivation
where,
Algorithm
Presentation the RHS is taken on the background day.
Ocean Reflectance
Land Minimum
Reflectance
˜
→ Raerosol = aerosol background reflectance
AOD Retrieval
Validation fixed background value for AOD = 0.03
Examples
Aerosol Radiative
Forcing
Conclusions
AOD Retrieval
Detection of
aerosols and other
climatological
effects by remote
sensing using
GERB/SEVIRI
Rsurface is now known.
Stijn Nevens
Retrieval performed for 6 different aerosol classes:
Introduction Derived from an analysis of AERONET retrieval.
GERB Maritime model WMO, moderately absorbing,
Aerosol Detection continental WMO, urban-industrial, smoke and
Motivation
Algorithm spherical dust.
Presentation
Ocean Reflectance All are spherical and some are too similar.
Land Minimum
Reflectance → Introduction of different (non-spherical) aerosol models.
AOD Retrieval
Validation
Examples
AOD is calculated form a best fit using the 3 solar
Aerosol Radiative channels with simulated reflectances using LUT.
Forcing
Conclusions
Validation
Detection of
aerosols and other
climatological Based on comparison with AERONET observations.
effects by remote
sensing using
GERB/SEVIRI
July 2006: > 200 co-registrations with Cabauw.
Stijn Nevens
Introduction
GERB
Aerosol Detection
Motivation
Algorithm
Presentation
Ocean Reflectance
Land Minimum
Reflectance
AOD Retrieval
Validation
Examples
Aerosol Radiative
Forcing
Conclusions
slope = 0.96 intercept = 0.02.
Observation Temporal Changes in Aerosol Load
Detection of
aerosols and other Dust event Dakar with AOD varying from > 2.0 till 0.3
climatological
effects by remote in 7 days.
sensing using
GERB/SEVIRI
Stijn Nevens
Introduction
GERB
Aerosol Detection
Motivation
Algorithm
Presentation
Ocean Reflectance
Land Minimum
Reflectance
AOD Retrieval
Validation
Examples
Aerosol Radiative
Forcing Same trends AERONET and SEVIRI.
Conclusions SEVIRI tends to underestimate the aerosol load.
→ Background day: assumed AOD = 0.03 + high AOD
during the reference period ⇒ systematic bias.
Dust storm across Central and West Africa
Detection of
aerosols and other
climatological
effects by remote
sensing using
GERB/SEVIRI
Stijn Nevens
Introduction
GERB
Aerosol Detection
Motivation
Algorithm
Presentation
Ocean Reflectance
Land Minimum
Reflectance
AOD Retrieval
Validation
Examples
Aerosol Radiative
Forcing
Conclusions
08/03/2004 Aqua Satellite
Example AOD (08/03/2004)
Detection of
aerosols and other
climatological
effects by remote
sensing using
GERB/SEVIRI
Stijn Nevens
Introduction
GERB
Aerosol Detection
Motivation
Algorithm
Presentation
Ocean Reflectance
Land Minimum
Reflectance
AOD Retrieval
Validation
Examples
Aerosol Radiative
Forcing
Conclusions
Outline
Detection of
aerosols and other
climatological Introduction
effects by remote
sensing using
GERB/SEVIRI
GERB
Instrument
Stijn Nevens
Products
Introduction
Aerosol Detection
GERB
Motivation
Aerosol Detection
Algorithm Presentation
Aerosol Radiative
Forcing Ocean Reflectance
Conclusions Land Minimum Reflectance
AOD Retrieval
Validation
Examples
Aerosol Radiative Forcing
Conclusions
Methodology
Detection of
aerosols and other
With low AOD there is a linear relation between (clear sky)
climatological
effects by remote
radiative forcing and AOD.
sensing using
GERB/SEVIRI
Stijn Nevens
Introduction
GERB
Aerosol Detection
Aerosol Radiative
Forcing
Conclusions
LLoeb, Norman G., Seiji Kato, 2002)
Methodology (bis)
Detection of
aerosols and other
climatological
effects by remote
sensing using
Use this relation to calculate slope and intercept in a
GERB/SEVIRI TRS (or TET) - AOD graph.
Stijn Nevens
Slope: radiative forcing corresponding with give AOD.
Introduction
GERB
Aerosol Detection
Aerosol Radiative
Forcing
Conclusions
Outline
Detection of
aerosols and other
climatological Introduction
effects by remote
sensing using
GERB/SEVIRI
GERB
Instrument
Stijn Nevens
Products
Introduction
Aerosol Detection
GERB
Motivation
Aerosol Detection
Algorithm Presentation
Aerosol Radiative
Forcing Ocean Reflectance
Conclusions Land Minimum Reflectance
AOD Retrieval
Validation
Examples
Aerosol Radiative Forcing
Conclusions
Conclusions
Detection of
aerosols and other
climatological
effects by remote
sensing using GERB: provides many interesting products (both direct
GERB/SEVIRI
and derived).
Stijn Nevens
Aerosols algorithm: constant background AOD of 0.03
Introduction
unrealistic in high AOD periods.
GERB
Aerosol Detection
→ Use different algorithm to improve estimation of
Aerosol Radiative
background AOD.
Forcing
Aerosol retrieval works only when Rsurface is small (dark
Conclusions
surface).
→ Use different algorithm for bright surfaces (desert).
We can combine our products to calculate aerosol
radiative forcing.
Conclusions
Detection of
aerosols and other
climatological
effects by remote
sensing using GERB: provides many interesting products (both direct
GERB/SEVIRI
and derived).
Stijn Nevens
Aerosols algorithm: constant background AOD of 0.03
Introduction
unrealistic in high AOD periods.
GERB
Aerosol Detection
→ Use different algorithm to improve estimation of
Aerosol Radiative
background AOD.
Forcing
Aerosol retrieval works only when Rsurface is small (dark
Conclusions
surface).
→ Use different algorithm for bright surfaces (desert).
We can combine our products to calculate aerosol
radiative forcing.
Conclusions
Detection of
aerosols and other
climatological
effects by remote
sensing using GERB: provides many interesting products (both direct
GERB/SEVIRI
and derived).
Stijn Nevens
Aerosols algorithm: constant background AOD of 0.03
Introduction
unrealistic in high AOD periods.
GERB
Aerosol Detection
→ Use different algorithm to improve estimation of
Aerosol Radiative
background AOD.
Forcing
Aerosol retrieval works only when Rsurface is small (dark
Conclusions
surface).
→ Use different algorithm for bright surfaces (desert).
We can combine our products to calculate aerosol
radiative forcing.
Conclusions
Detection of
aerosols and other
climatological
effects by remote
sensing using GERB: provides many interesting products (both direct
GERB/SEVIRI
and derived).
Stijn Nevens
Aerosols algorithm: constant background AOD of 0.03
Introduction
unrealistic in high AOD periods.
GERB
Aerosol Detection
→ Use different algorithm to improve estimation of
Aerosol Radiative
background AOD.
Forcing
Aerosol retrieval works only when Rsurface is small (dark
Conclusions
surface).
→ Use different algorithm for bright surfaces (desert).
We can combine our products to calculate aerosol
radiative forcing.
Conclusions
Detection of
aerosols and other
climatological
effects by remote
sensing using GERB: provides many interesting products (both direct
GERB/SEVIRI
and derived).
Stijn Nevens
Aerosols algorithm: constant background AOD of 0.03
Introduction
unrealistic in high AOD periods.
GERB
Aerosol Detection
→ Use different algorithm to improve estimation of
Aerosol Radiative
background AOD.
Forcing
Aerosol retrieval works only when Rsurface is small (dark
Conclusions
surface).
→ Use different algorithm for bright surfaces (desert).
We can combine our products to calculate aerosol
radiative forcing.
Conclusions
Detection of
aerosols and other
climatological
effects by remote
sensing using GERB: provides many interesting products (both direct
GERB/SEVIRI
and derived).
Stijn Nevens
Aerosols algorithm: constant background AOD of 0.03
Introduction
unrealistic in high AOD periods.
GERB
Aerosol Detection
→ Use different algorithm to improve estimation of
Aerosol Radiative
background AOD.
Forcing
Aerosol retrieval works only when Rsurface is small (dark
Conclusions
surface).
→ Use different algorithm for bright surfaces (desert).
We can combine our products to calculate aerosol
radiative forcing.
Conclusions
Detection of
aerosols and other
climatological
effects by remote
sensing using GERB: provides many interesting products (both direct
GERB/SEVIRI
and derived).
Stijn Nevens
Aerosols algorithm: constant background AOD of 0.03
Introduction
unrealistic in high AOD periods.
GERB
Aerosol Detection
→ Use different algorithm to improve estimation of
Aerosol Radiative
background AOD.
Forcing
Aerosol retrieval works only when Rsurface is small (dark
Conclusions
surface).
→ Use different algorithm for bright surfaces (desert).
We can combine our products to calculate aerosol
radiative forcing.
Shared by: xiaohuicaicai
Other docs by xiaohuicaicai
brochure1 second generation third generation first generation Associates Inc
Views: 4 | Downloads: 0
