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Modeling the Impact of Drizzle and 3D Cloud Structure on Remote Sensing of Effective RadiusRemote sensing of cloud particle size with passive sensors like MODIS is an important tool for cloud microphysical studies. As a measure of the radiatively relevant droplet size, effective radius can be retrieved with different combinations of visible through shortwave infrared channels. MODIS observations sometimes show significantly larger effective radii in marine boundary layer cloud fields derived from the 1.6 and 2.1 pm channel observations than for 3.7 pm retrievals. Possible explanations range from 3D radiative transport effects and sub-pixel cloud inhomogeneity to the impact of drizzle formation on the droplet distribution. To investigate the potential influence of these factors, we use LES boundary layer cloud simulations in combination with 3D Monte Carlo simulations of MODIS observations. LES simulations of warm cloud spectral microphysics for cases of marine stratus and broken stratocumulus, each for two different values of cloud condensation nuclei density, produce cloud structures comprising droplet size distributions with and without drizzle size drops. In this study, synthetic MODIS observations generated from 3D radiative transport simulations that consider the full droplet size distribution will be generated for each scene. The operational MODIS effective radius retrievals will then be applied to the simulated reflectances and the results compared with the LES microphysics.
Document ID
20080044858
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Platnick, Steven
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Zinner, Tobias
(Deutsche Forschungsanstalt fuer Luft- und Raumfahrt Wessling, Germany)
Ackerman, S.
(NASA Goddard Inst. for Space Studies New York, NY, United States)
Date Acquired
August 24, 2013
Publication Date
August 3, 2008
Subject Category
Meteorology And Climatology
Meeting Information
Meeting: International Radiation Symposium
Location: Foz do Iguacu
Country: Brazil
Start Date: August 3, 2008
End Date: August 8, 2008
Sponsors: Instituto de Astronomia y Fisica del Espacio
Distribution Limits
Public
Copyright
Other

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