The Analysis of Surface Pressure Perturbations Within the Mesoscale Range

Abstract

By means of an extremely sensitive pressure transducer and a digital recording system, atmospheric pressure measurements were made for a two-week period in October 1971. A three-station array, roughly triangular in shape, was set up within the Miami, Fla., area so as to obtain the phase speed and direction of pressure perturbations moving through the array. Single-station and multiple-station analysis was limited to the range of frequencies from 8 ? 10?3 to 4 ? 10?2 cycles min?1. By analysing the band-pass filtered time series and power spectrum for a two-week period, dominant frequencies were observed within the power spectrum. Analyzing the time series for both fair and disturbed conditions, the amplitude of the pressure perturbations ranged from 0.4 mb for fair weather up to 1.0 mb for disturbed weather conditions. The analysis of the power spectrum and cross spectrum for all three stations for a three-day period indicates that for this period there were three predominant frequencies. From the phase spectrum these waves were shown to move from the east, or approximately in the direction of the low-level flow, and in each case moved with a speed of about 60 kt.