The Use of Limited Surface Networks to Measure Mesoscale Phenomena

Abstract

Large mesonetworks have successfully demonstrated coupling of surface meteorological phenomena to convective activity. It is unrealistic however, to assume that such networks will be available for wide-area operational applications. This paper examines an alternative to large mesonetworks which applies a limited number of closely spaced (10?20 km) stations to describe meso?, meso-? phenomena. The techniques are applied to data from the Cooperative Convective Precipitation Experiment conducted in southeast Montana during the summer of 1981. Examples are presented for a benign day, a day having limited convective activity, and a period having a severe convective storm. Each of these periods shows distinctive trends of convergence, vorticity and total atmospheric energy. Surface convergence shows little variance during the quiescent portions of the day. Heating and convection are accompanied by increased variance of convergence and a more organized character of its time plots. The vertical component of vorticity shows similar characteristics. Convection is evident as perturbations of atmospheric energy upon the diurnal trend. The magnitudes of these are, not surprisingly, correlated to the intensity of convection. The consistency of the results suggests the operational use of small clusters of closely spaced automatic surface stations for nowcasting applications.