Comparison of systematic errors in two forecast models with similar dynamical frameworks

A. D. Vernekar, J. Zhou, B. Kirtman

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Here a comparison of forecast errors in the AFGL (Air Force Geophysics Laboratory) and COLA (Center for Ocean-Land-Atmosphere Interactions) models is made with the expectation of identifying the causes of forecast errors. The two models are based on identical approximations in simulating the dynamical processes and only minor differences in parameterizations of the physical processes. Nine 10-day forecasts are made to study the error characteristics in the two models. The errors in the 500 mb geopotential height are negative in tropics and positive in extratropics. The temperatures at 850 mb are colder than observed in tropics and warmer than observed in extratropics. At 150 mb the temperatures are warmer than observed in tropics and colder than observed in extratropics. The tropical error in the AFGL model is larger than that in the COLA model. The AFGL model, relative humidity errors are negative largely over the ocean and positive over land with minor exceptions. This error structure differs from that of the COLA model which consists of mostly positive errors everywhere with some small regions of negative errors. The major differences in the physical parameterizations between the two models are in the radiation interaction with deep convective clouds, the manner in which the sea surface temperature (SST) is prescribed, and the vertical transport of heat and moisture by shallow convection. -from Authors

Original languageEnglish (US)
Pages (from-to)207-231
Number of pages25
JournalAtmosfera
Volume5
Issue number4
StatePublished - Jan 1 1992
Externally publishedYes

ASJC Scopus subject areas

  • Atmospheric Science

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