Rain rate and drop size distribution measurements in Malaysia

Satellites for television, telephone and data communication employ ever-increasing radio frequencies in order to satisfy the growing demand for communications. At frequencies above 10 GHz, the effects on radio propagation of clouds, snow and, in particular, rain have to be considered. Measured data, and models to predict the effect of rain on communication systems, are therefore required before establishing satellite communication systems. Crane (1990) has indicated that out of 317 rain attenuation data bases available from CCIR either from radiometer or beacon receiver measurements, only 18 are in the wet tropical region. In view of the importance of such data, several measurement programmes have recently been made or proposed throughout the world concentrating on tropical regions. Preliminary results of rain behaviour in wet tropical climates such as in Indonesia, Papua New Guinea and Malaysia have already been reported. However, it is too early to derived a definitive attenuation model since long term data collection is required and each location has a different geographical nature which plays a significant role in the rain rate distribution. In this paper the results of one year programme of measurements of rain rate and drop size distribution (DSD) are presented