Tuesday, 4 June 2002
A One-Year Climatology Of Cloud Properties Derived From GOES-8 Over The Southeastern Pacific For PACS
The overall goal of Pan-American Climate Studies (PACS) program is to extend the scope and improve the
skill of operational climate prediction over the Americas. The atmosphere over the southeastern Pacific
(SEP) plays an important role in the general circulation, El Nino anomalies, and the weather over North,
Central, and South America. Meteorological observations over the SEP are sparse causing large
uncertainties in initialized model fields. Although not currently used in assimilations, cloud properties and
radiation fields are important components of the weather and climate system and should be faithfully
reproduced in models that simulate and predict the atmospheric state from the meso- to global scales.
Satellite observations are the only practical means to acquire the necessary parameters over the SEP for
model validation and future assimilation. This paper presents the results of an analysis of day and night
time 3-hourly multispectral GOES-8 data to derive cloud macrophysical and microphysical properties as
well as the radiation budget over the SEP and adjacent continental areas. Monthly mean values for cloud
amount, height, phase, effective particle size, optical depth, and liquid/ice water path, shortwave albedo,
and top-of-atmosphere longwave flux are derived on a 1.0° latitude-longitude grid for a domain
encompassed by 20°N, 40°S, 60°W, and 115°W for the 2000 calendar year. Special attention is given to
the periods of April 20 through May 15, and October 17 through November 12 when National Oceanic and
Atmospheric Administration research vessels (R/V) were collecting a wide range of meteorological and
oceanographic data in the domain. Data from instruments aboard the R/Vs are used to validate the cloud
retrievals from GOES-8. These analyses are an important step in the process of developing climatologies
of cloud and radiation properties for use in meso- and large-scale models of the circulation in the
southeastern Pacific.
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