There are thousands of stations throughout the world where rainfall observations and records are made. Included in such records is the fall of snow, reduced to its equivalent in rain. Rainfall is measured, in terms of inches or millimeters of depth, by means of a simple receptacle-and-gauge apparatus or by more complex electrical or weighing devices placed where eddies of air will not interfere with the normal fall of the raindrops. In addition to the daily, monthly, and annual totals, the depth of individual rainfalls and their intensity (amount of rain falling during a specific period of hours or minutes) and other pertinent facts are recorded.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.