Breakpoint Representation of Rainfall

Abstract

Pluviographs show there is a strong tendency for rain to abruptly change from one steady rate of fall to another, with these steady rates persisting for some time. This observation can be used to improve upon the traditional representation of rainfall that arose from the method of measurement but did not change with the advent of automatic gauges. Digitizing from pluviographs the times of change from one steady rain rate to another results in the breakpoint ?style? of representation in which the new rate and its time of commencement are noted. This style is very different from the traditional one, in which the integrated total over some fixed period is noted, since it provides a complete record of rainfall with information on intensities that is of great value when considering rainfall processes and for engineering applications. Some examples of the advantages of this new style of data are given. A wide network of pluviograph gauges exists but is likely to be lost with further automation: a new automatic gauge that directly provides breakpoint data is needed.