Accession Number : AD0666772

Title :   HARMONIC ANALYSIS OF PRECIPITATION.

Descriptive Note : Technical rept.,

Corporate Author : ARMY ELECTRONICS COMMAND FORT MONMOUTH N J

Personal Author(s) : Lowenthal,Marvin J.

Report Date : NOV 1967

Pagination or Media Count : 34

Abstract : Periodicities in monthly precipitation over North America are investigated using harmonic analysis. The long term means are expressed by a trigonometric function (cosine or sine) with periods of 12, 6, and 4 months. Amplitudes and phase angles are examined with the goodness of fit determined by analyzing the residual variances after the application of one, two, and three harmonics. The variation of precipitation in the interior of North America may be satisfactorily expressed as a simple cosine curve with a summer maximum and an amplitude of about one inch. Adding the second and third harmonic reduces the residual variance to less than 20% in all but three small scattered areas. The physical reasoning behind this mathematical technique is not immediately evident since synoptic phenomena occurring at three-month intervals are not clear. (Author)

Descriptors :   (*ATMOSPHERIC PRECIPITATION, PERIODIC VARIATIONS), NORTH AMERICA, HARMONIC ANALYSIS, TRANSCENDENTAL FUNCTIONS, ANALYSIS OF VARIANCE, MATHEMATICAL PREDICTION, METEOROLOGICAL CHARTS

Subject Categories : Meteorology

Distribution Statement : APPROVED FOR PUBLIC RELEASE