Correlation of millimeter-band radio-wave attenuation in cloud and rain parts of cloud-rain system

Abstract

The experimentally detected difference by a factor of two or more of the autocorrelation times of millimeter-wave attenuation in the rain and cloud parts of a cloud-rain system is examined. In cases of moderate to heavy rain, the measured autocorrelation time of millimeter-wave attenuation in the cloud part of the system is greater by a factor of two than that in the rain for a given degree of cloudiness. In the case of drizzle, the measured relationship is inverted: the attenuation autocorrelation time in the rain part exceeds that in the cloud part by a factor of two. Specific realizations are used; the problem of estimation of the average correlation-time relationships, which is required for prolonged measurement periods, is not posed; nevertheless, the need for its formulation follows from the results considered here. The physical meaning of the results is that the horizontal spatial heterogeneities of moderate to heavy rain are smaller than those of drizzle and greater than those of the clouds from which the given rain falls.