GIFTS/IOMI Cloudy/Aerosol Forward Model Development

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• GIFTS/IOMI Cloudy/Aerosol Forward Model
  Development
• Steve Ackerman, Dave Tobin, Leslie Moy, host of
  others.
• University of Wisconsin - Madison
• May 14 - 15, 2002
• Review of overall goals
• The need to couple cloud/aerosol model to fast
  model transmittances
• Status of ongoing activities
• Detailed model
• Retrieval model

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GIFTS/IOMI Aerosol Laden Forward Model
Development Relationship to MURI Objectives The
primary objective of this processing algorithm is
to detect the presence of suspended matter such
as dust, sand, volcanic ash, or smoke, especially
near the surface and in the boundary layer.
Detection of suspended matter is based on the
spectral variations of these aerosol radiative
properties this approach has been moderately
successful using radiometric measurements with
low spectral resolution in the infrared
wavelengths, and will significantly be improved
with high-spectral resolution observations.
Modeling is important for understanding the
physics behind the algorithms, but observations
are required to truly test and verify the
techniques. Brief Scientific Description of
Work Identify specific radiative signatures of
aerosols in high-spectral resolution
observations. The basic tasks include 1) perform
a series of trade studies designed to determine
the accuracy of the existing fast models and to
determine ways to improve the existing model, 2)
perform detailed forward modeling to interpret
the aerosol signatures spectra 3) development
of detection and aerosol retrieval algorithms for
use with high-spectral observations Plans as they
pertain to MURI Goals An accurate and fast
cloud/aerosol laden sky forward model is required
for producing simulated GIFTS/IOMI data and for
several of the retrieval algorithms under
development. Coordination with the clear-sky
modeling is required to assure consistency.
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Generic Fast Model Production Flowchart
R ( esB(Ts) rs ) tz(L) Sl1L B(T(l)) (tz
(l -1) - tz (l) ) keff -ln (teff ) Si1N ci
Qi teff (l) tz (l) / tz (l -1)
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Observed Radiances
Atmospheric and surface properties

• The retrieval cycle

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Observed Radiances
Retrieval Models
Reflectance (R?), Transmittance (T ?),
Absorptance (A ?)Emittance(? ?)
Temperature and Gas Incident Fluxes
Single Scattering Properties ? ? , ?º , P(?, ?)
Macrophysical properties
Cloud or aerosol Microphysics n(r), n(h), mmr-imi
Forward Models
The retrieval cycle
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Current GIFTS/IOMI Cloud/Aerosol RTE Model
Activities

• Super-window correlated-K DISORT calculations
  Used in retrieval of cloud/aerosol properties.
• Fast model with cloud effective emissivity.
• Doubling/Adding model that uses LBLRTM layer
  optical depths, CPU intensive but needed for
  error studies.
• Another approach?
• Single Scattering Properties

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GIFTS/IOMI Data Cube Simulations
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MODIS Example
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Simulations
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Simulations
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Example from cloud application (Antonelli,
Nasiri, Baum, Yang,
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Current On-going Activities

• Examine differences in full-blown multiple
  scattering model (doubling/adding with LBLRTM
  monochromatic optical) with fast-model
  approximate methods.
• Quantify spectral errors in the fast-model
  approaches with respect to expected errors in
  retrieval objectives and as a function of aerosol
  micro-phyiscal and macro-physical properties
• Select appropriate radiative transfer model for
  aerosol detection and property retrievals
  (effective emissivity, super-window, some
  combination).
• Coordinate activities with the clear-sky folks
  to get appropriate profile databases in the fast
  model production.

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AVHRR Observations
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AVHRR ObservationsBT11-BT12
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AVHRR ObservationsFrequency of BT11-BT12 lt 0

• March - May 2000

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AVHRR Observations
June 1999
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AVHRR Observations
July 1999
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AVHRR ObservationsFrequency of BT11-BT12 lt 0

• March - May 2000

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AVHRR Observations
June 1999
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AVHRR Observations
July 1999
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AVHRR Observations
August 1999
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AVHRR Observations
September 1999
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AVHRR Observations
October 1999
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AVHRR Observations
November 1999
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AVHRR Observations
December 1999
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AVHRR Observations
Jan-Feb 2000
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