Accession Number : AD0803354

Title :   MODIFICATION OF THE FJORTOFT GRAPHICAL PROGNOSIS METHOD.

Descriptive Note : Master's thesis,

Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s) : Clark, Stanley Davis, Sr. ; Langemo, James Carroll

Report Date : OCT 1966

Pagination or Media Count : 67

Abstract : This paper presents a relatively simple method for producing a 24-hour prognostic 500-mb chart by graphical means. It modifies the Fjortoft graphical method by incorporating a technique to include the intensification and weakening of systems. That is, it uses factors which allow intensification of poleward-moving cyclones and weakening of equatorward-moving cyclones and the converse for anti-cyclones. The theoretical development of the so-called 'geostrophic model' used, the research procedure, and a number of illustrative charts are all discussed and a table of chart verification scores is presented to assist in the reader's evaluation of the method. It is concluded that this method does provide a simple prognostic procedure which includes some intensity change for systems. The results showed an average 24.9% improvement over persistence for the charts analyzed using a height-gradient verification scheme. Appendix 1 outlines the specific procedure for utilizing the method on a practical basis and is included as such for the convenience of potential users. (Author)

Descriptors :   *WEATHER FORECASTING), (*METEOROLOGICAL CHARTS, ATMOSPHERIC MOTION, CYCLONES, ANTICYCLONES, ATMOSPHERE MODELS, INTENSITY, ALTITUDE, BAROMETRIC PRESSURE, VORTICES, WIND, NUMERICAL ANALYSIS, NORTH AMERICA, PACIFIC OCEAN, NORTHERN HEMISPHERE, ATLANTIC OCEAN, EQUATIONS, GRAPHICS, DIURNAL VARIATIONS.

Subject Categories : Meteorology
      Cartography and Aerial Photography

Distribution Statement : APPROVED FOR PUBLIC RELEASE