Cloud shading retrieval and assimilation in a satellite-model coupled mesoscale analysis system

Journal Article · Mon Nov 01 04:00:00 EST 1993 · Monthly Weather Review; (United States)

DOI:https://doi.org/10.1175/1520-0493(1993)121<3062:CSRAAI>2.0.CO;2· OSTI ID:5510861

Lipton, A E ^[1]

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1. Phillips Lab., Hanscom AFB, MA (United States)

A retrieval-assimilation method has been developed as a quantitative means to exploit the information in satellite imagery regarding shading of the ground by clouds, as applied to mesoscale weather analysis. Cloud radiative parameters are retrieved from satellite visible image data and used, along with parameters computed by a numerical model, to control the model's computation of downward radiative fluxes at the ground. These fluxes influence the analysis of ground surface temperatures under clouds. The method is part of a satellite-model coupled four-dimensional analysis system that merges information from visible image data in cloudy areas with infrared sounder data in clear areas, where retrievals of surface temperatures and water vapor concentrations are assimilated. The substantial impact of shading on boundary-layer development and mesoscale circulations was demonstrated in simulations, and the value of assimilating shading retrievals was demonstrated with a case study and with a simulated analysis that included the effects of several potential sources of error. The case study was performed in the northwestern Texas area, where convective cloud development was influenced by the shading effects of a persistent region of stratiform cloud cover. Analyses that included shading retrieval assimilation had consistently smaller shelter-height temperature errors than analyses without shading retrievals. When clear-area surface temperature retrievals from sounder data were analyzed along with cloudy-area shading retrievals, the contrast in heating between the shaded and clear parts of the domain led to large variations in analyzed boundary-layer depths and had a modest impact on analyzed wind flow. The analyzed locations of upward vertical motion corresponded roughly to areas of convective cloud development observed in satellite imagery. 29 refs., 17 figs., 2 tabs.

• OSTI ID: 5510861
• Journal Information: Monthly Weather Review; (United States), Journal Name: Monthly Weather Review; (United States) Vol. 121:11; ISSN MWREAB; ISSN 0027-0644
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110*
ATMOSPHERIC CIRCULATION
BOUNDARY LAYERS
CLIMATE MODELS
CLOUD COVER
CLOUDS
COMPUTERIZED SIMULATION
DEVELOPED COUNTRIES
ELECTROMAGNETIC RADIATION
FLUIDS
FOUR-DIMENSIONAL CALCULATIONS
GASES
HEAT FLUX
INFRARED RADIATION
LAYERS
MATHEMATICAL MODELS
METEOROLOGY
NORTH AMERICA
RADIATIONS
REMOTE SENSING
SATELLITES
SHADING
SIMULATION
TEMPERATURE DEPENDENCE
TEXAS
USA
VAPORS
WATER VAPOR
WEATHER