chapter  4
31 Pages

Atmospheric moisture budget

The average storage of water vapor in the atmosphere (Table 4.1), termed the precipitable water content (about 25mm), is sufficient for only about 10 days, supply of rainfall over the earth as a whole. However, intense (horizontal) influx of moisture into the air over a given region makes possible short-term rainfall totals greatly in excess of 30mm. The phenomenal record total of 1870mm fell on the island of Réunion, off Madagascar, during 24 hours in March 1952, and much greater intensities have been observed over shorter periods (see E.2a, this chapter).