Accession Number : AD0721186

Title :   Studies of Clouds and Weather over Southeast Asia.

Descriptive Note : Air Force surveys in geophysics,

Corporate Author : AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS

Personal Author(s) : Conover,John H.

Report Date : 21 JAN 1971

Pagination or Media Count : 47

Abstract : A radar weather index forecast was used to provide a measure of precipitation coverage which in turn would serve as a guide to more detailed forecasts of ceiling, visibility, etc. The index equals the percent coverage by radar echoes within a 50-nmi radius of the station. Hourly indices were computed for Tan Son Nhut, Pleiku, Ubon, and Udorn. From the analysis of cloudiness, winds, and pressure distributions it was found that weather over the three southernmost stations is best related to prior conditions to the east. Activity at the northernmost sstation also relates to prior conditions to the east, but weak pressure correlations are also found over the Tibetian Highlands and western Indochina, suggesting an influence from the northwest and west. Using a stepwise multiple regression program, equations were developed for forecasting 1,2, and 3 days in advance the probability that the radar index in the afternoon, 1230 to 2330 LT, would be low, average, or high. Variables of cloudiness, sea level pressure, and pressure gradients were found most useful. Nomograms were made to simplify calculations of the forecasts. (Author)

Descriptors :   (*CLOUD COVER, *SOUTHEAST ASIA), (*WEATHER FORECASTING, SOUTHEAST ASIA), (*ATMOSPHERIC PRECIPITATION, RADAR CROSS SECTIONS), CEILING, VISIBILITY, WIND, PROBABILITY, METEOROLOGICAL RADAR, MATHEMATICAL MODELS, REGRESSION ANALYSIS, WEATHER STATIONS, METEOROLOGICAL SATELLITES, AIR FORCE OPERATIONS

Subject Categories : Meteorology

Distribution Statement : APPROVED FOR PUBLIC RELEASE