Accession Number : AD0433600


Title :   PROGNOSTIC RELATIONS DEVELOPED BETWEEN CIRCULATION VARIABLES AND TOTAL CLOUD AMOUNT BY STATISTICAL METHODS,


Corporate Author : TRAVELERS RESEARCH CENTER INC HARTFORD CONN


Personal Author(s) : Ostby,Frederick P ; Chisholm,Donald A


Report Date : Mar 1964


Pagination or Media Count : 126


Abstract : For predicting total cloud amount, screeningregression equations (12-, 24-, and 36-hr predictions) and multiple-discriminant-analysis (MDA) probability tables (24-hr prediction only) were derived by statistical methods from a 5-day sample of upper-air analyses and prognoses from Feb. 1962. Significant predictors were found to be total-cloud-amount persistence, moisture content (CPS), vertical velocity, 850-500-mb thickness, 500-mb height, wind divergence, thickness advection, and zonal and meridional wind components. Relations were derived to include prognostic terms only, lagged-analysis terms only, and a combination of the two. Application of the relations to the dependent data and to a small sample (194 cases) of independent data showed that: (a) relations based on prognostic variables and persistence (as predictors) are superior to the others; (b) MDA yields slightly better results than screening regression; (c) relations derived for cloud specification, when converted to prediction relations, do not yield as satisfactory results as prognostic relations; and (d) the statistical techniques yield results superior (based on percent-correct scores on independent data) to persistence or climatology. (Author)


Descriptors :   *CLOUDS , WEATHER FORECASTING , CLOUD COVER , STATISTICAL ANALYSIS , MATHEMATICAL PREDICTION


Distribution Statement : APPROVED FOR PUBLIC RELEASE