SAN FRANCISCO STATE UNIVERSITY SPRING 2008

DEPARTMENT OF GEOSCIENCES METR 485/785

Return Period

14 March 2008

A meteorologist or oceanographer is often asked to calculate the so-called "return period" of a preciptiation amount to establish the degree to which the rainfall total in question was statistically remarkable. The meteorologist may often also be asked to provide a client with the conceptual significance of the term "return period" and a brief descriptive overview on how such "return period" information was obtained. This presents the consultant with a dilemma since the description or explanation provided must be technically accurate wile rather qualitative.

The following should be included somewhere in your answer to CCM Question 2:

(a) the meaning of the term "return period" when referred to a rainfall amount or tsunami runoff (be as complete as possible here, including a discussion of what the term DOES NOT mean, as well);

(b) a conceptual explanation of how return period information is obtained for a particular station.

(c) a brief statement about the perils of “overinterpretation” of the return period information.

In formulating your answer, consider that the individual to which these explanations are directed is a juror with absolutely no science, mathematics or meteorology/oceanography background but who is reasonably intelligent.