Diurnal Variations in Convective Activity and Precipitation During Phases II and III of GATE

Abstract

Abstract Harmonic analysis is used to determine the phase and normalized amplitude of the diurnal variations in convective activity and precipitation during phases II and III of GATE. Satellite results are based on the percent coverage of squares, 3° of latitude and longitude in dimensions, by convective clouds, as estimated subjectively from SMS-1 infrared images. Rainfall results are based on hourly precipitation records for 33 land stations and hourly or 3-hourly rainfall amounts from 13 ships in the A/B-scale networks. The rainfall data for the land stations were combined into four geographically distinct groups and the ship data into a single group before making the harmonic analyses. The long-term representativeness of the results for the land areas is judged by comparing them with the results obtained from analysis of data presented by Burpee (1976) on the frequencies of occurrence of thunder, moderate to heavy precipitation and light precipitation during the period June-September 1966–69. The main...