Accession Number : ADA256668


Title :   Comparing Model-Produced Convective Cloudiness with Observations


Corporate Author : PHILLIPS LAB HANSCOM AFB MA


Personal Author(s) : Norquist, D C ; Yang, C


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a256668.pdf


Report Date : May 1992


Pagination or Media Count : 19


Abstract : Convective cloudiness generated by a parameterization scheme of a large-scale numerical weather prediction model was compared with analyses of clouds observed by geosynchronous satellites. The comparisons were performed over an equatorial Pacific Ocean region and the Amazon basin region for the period January-February 1979. Fractional coverage of predefined areas by clouds with tops in several altitude-temperature categories was averaged in each area for the entire period of record and also for individual times of the day. The overall mean provided a basis for comparison of the general spatial distributions of observed and model-produced cloud, while hourly departures from the overall mean allowed a comparison of the diurnal variations. Geosynchronous satellite cloud analysis serves as a useful reference for assessing the performance of a moist convective parameterization scheme. In this case, it was found that the subject convective scheme produces an accurate relative horizontal distribution of convective cloudiness, but produces too large a proportion of deep convection in the scheme. The diurnal variation of model- produced convection was 9-12 h out of phase and somewhat smaller in magnitude than the observed variation over the ocean region. Good agreement was noted between the diurnal characteristics of observed variation over the ocean region. Good agreement was noted between the diurnal characteristics of observed cloud and model-produced convection over the land region.


Descriptors :   *CLOUDS , *WEATHER FORECASTING , *METEOROLOGY , *CONVECTION(ATMOSPHERIC) , REPRINTS , PACIFIC OCEAN , CUMULUS CLOUDS , DIURNAL VARIATIONS , ALTITUDE , PREDICTIONS , MODELS , METEOROLOGICAL SATELLITES


Subject Categories : Meteorology


Distribution Statement : APPROVED FOR PUBLIC RELEASE