Jun 27, 202 2 Carbonaceous Aerosol Workshop Page 1 NASA GISS How can satellites help define the history of carbonaceous aerosols in the industrial era. • Acknowledgements: – Paris Workshop - September 2003 organized by Didier Tanré and Yoram Kaufman: Slides abstracted from the talks of M. Herman (POLDER), G. De Leeuw (ATSR), O. Torres (TOMS), C. Hsu (SeaWiFs), L. Remer (MODIS) and D. Diner (MISR), G. Myhre (comparison).
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NASA GISS 21-Nov-15 Carbonaceous Aerosol Workshop Page 1 How can satellites help define the history of carbonaceous aerosols in the industrial era. Acknowledgements:
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Apr 21, 2023 Carbonaceous Aerosol Workshop Page 1
NASA GISS
How can satellites help define the history of carbonaceous aerosols
in the industrial era.• Acknowledgements:
– Paris Workshop - September 2003 organized by Didier Tanré and Yoram Kaufman: Slides abstracted from the talks of M. Herman (POLDER), G. De Leeuw (ATSR), O. Torres (TOMS), C. Hsu (SeaWiFs), L. Remer (MODIS) and D. Diner (MISR), G. Myhre (comparison).
Apr 21, 2023 Carbonaceous Aerosol Workshop Page 2
NASA GISS
How can satellites help define the history of carbonaceous aerosols in the industrial era
– Satellites do not measure optical depth (except for solar
occultation for stratospheric aerosols) they measure reflectance
– Assumptions are required about size, shape and refractive index
in retrievals
– More measurements reduces the number of assumptions
– More measurements are:
• More wavelengths
• More angles
• More elements in the Stokes vector (polarization)
• All of the above
Apr 21, 2023 Carbonaceous Aerosol Workshop Page 3
NASA GISS
– VIS/NIR/SWIR single view measurements
• AVHRR on POESS, MODIS on Terra and Aqua, GLI and OCTS on
ADEOS, SeaWiFS, CZCS.
• Magnitude and spectral variation of radiances used to estimate size
and optical depth of aerosols.
• Easier over ocean where the surface has a fairly well defined
contribution
How can satellites help define the history of carbonaceous aerosols in the industrial era
Apr 21, 2023 Carbonaceous Aerosol Workshop Page 4
NASA GISS
– VIS/NIR/SWIR single view measurements• Can estimate aerosol load over land
• Land surface variability is a problem particularly for bright surfaces since land
is generally brighter than the atmosphere but can be solved to some extent
How can satellites help define the history of carbonaceous aerosols in the industrial era
Apr 21, 2023 Carbonaceous Aerosol Workshop Page 5
NASA GISS
– VIS/NIR/SWIR single view measurements
How can satellites help define the history of carbonaceous aerosols in the industrial era
MODIS burn scar Aug 23, 2000
MODIS AOT Aug 23, 2000
MODIS fire/smoke Aug. 23 2000
MODIS Fire Temp. Aug 23, 2000
MOPITT CO Aug 22-27
Apr 21, 2023 Carbonaceous Aerosol Workshop Page 6
NASA GISS
Winter Spring
Summer Autumn
*Hsu et al. 2003, submitted
– VIS/NIR/SWIR single view measurements• Even over deserts blue/UV measurements can be used to estimate aerosol
optical depth and single scattering albedo.
How can satellites help define the history of carbonaceous aerosols in the industrial era
Apr 21, 2023 Carbonaceous Aerosol Workshop Page 7
NASA GISS
– UV measurements (340/380 nm on TOMS)• TOMS, OMI on Aura, OMPS on NPOESS. Also possible using
measurements from the European GOME and SCHIAMACHY instruments.• Use effect of absorbing aerosols on the amount of molecular scattering that
occurs.• Land is less of a problem than VIS/NIR because surface is dark and
atmosphere is bright. Sensitive to vertical extent of aerosols.
How can satellites help define the history of carbonaceous aerosols in the industrial era
Apr 21, 2023 Carbonaceous Aerosol Workshop Page 8
NASA GISS
Sept. 4/2002
SeaWIFS RGB
EP-TOMS TOMS-AERONET AOT comparison
ssa= 0.97`
(A. ChaikovskyMinsk, Earlinet)
How can satellites help define the history of carbonaceous aerosols in the industrial era
Apr 21, 2023 Carbonaceous Aerosol Workshop Page 9
NASA GISS
– Multi-angle measurements• POLDER - up to 14 view angles with polarization in some bands
• MISR - high spatial resolution multi-angle and multi-spectral retrievals, spectral range 440-865 nm with nine view
angles
• ATSR, ATSR-2, AATSR on ERS satellites- broader spectral range with two view angles.
• Potential to identify non-spherical particles
How can satellites help define the history of carbonaceous aerosols in the industrial era
How can satellites help define the history of carbonaceous aerosols in the industrial era
– Polarization measurements• Identification of non-spherical
particles more straightforward with polarization measurements,
• Sensitivity of polarization to refractive index of aerosols can be used to identify aerosol type, particularly differentiation of smoke from sulfates.
• Retrievals (and POLDERs index) work over land because the surface polarized reflectance is grey which allows the 2250 nm polarized reflectance to be used as a proxy for the surface even when the surface albedo is bright and/or variable (e.g. at 555 and 865 nm). Including over deserts and urban areas such as LA.
How can satellites help define the history of carbonaceous aerosols in the industrial era
•What sort of differences do different species show in polarization?
•East coast summer time haze over the Dismal swamp shows polarized reflectance increasing with frequency indicating small particles with a refractive index consistent with a hydrated salt of some kind.
How can satellites help define the history of carbonaceous aerosols in the industrial era
•West coast fires, 10-29-03. Size and refractive index of smoke aerosols are substantially different to the haze. Still small but appear to have very high real refractive index and single scattering albedo of order 0.9.
•Implication is that POLDER should have particularly good sensitivity to smoke in its aerosol index.
How can satellites help define the history of carbonaceous aerosols in the industrial era