Introduction

Many studies have been carried out of the rainfall characteristics of most of the regions affected by the monsoons, and extensive records exist in many countries. In more recent years, however, the emphasis in regional observational studies has tended to be placed more on the analysis of weather patterns at various levels in the atmosphere in order to identify the structures of particular weather systems responsible for rainfall. Research has also been carried out which attempts to evaluate the various terms in the moisture budget in particular regions, for instance the net water vapour transport into the region and the accompanying evaporation and rainfall. Chapters 12 to 28 describe such regional studies.

Chapter 12 concentrates on the role of the upper-tropospheric anticyclone during the summer monsoon onset, while in Chapters 13 and 14 aspects of the structures of weather systems responsible for particular monsoon rain events are described. Such events are shown, in Chapter 15, to be closely related to the pattern of sea-surface temperature in the Arabian Sea and Bay of Bengal. The rainfall distribution in the Himalayas is discussed in Chapter 16, and the rainfall over India as a whole is discussed in the full water vapour budget context in Chapter 17.

One of the basic problems of tropical meteorology is to determine the precise way in which the atmosphere organizes the upward transports of heat, moisture and momentum on a variety of different scales.