TEMPERATURE CHANGES DURING FORMATION AND DISSIPATION OF WEST COAST STRATUS

Abstract

At three-hourly intervals during three 24- to 48-hour periods in the summer of 1943, radiosonde observations were made at the University of California at Los Angeles; to ascertain the changes in vertical temperature distribution during typical stratus situations. These observations show that the base of the subsidence inversion characteristic of all summer soundings in this region undergoes marked diurnal variations in height and temperature. Computations show that advection can account for only part of the cooling at the inversion base during the formation of stratus over the station, while radiational exchange tends to raise the temperature there, rather than to lower it. Turbulence is shown to be practically negligible, and convection to play only a slight role. Vertical motion is found to account for the otherwise unexplained changes in temperature and inversion height. A possible cause of vertical motion with diurnal period is convergence in the land and sea breeze.