Probable Maximum Precipitation Estimation Using the Revised Km-Value Method in Hong Kong
Annotatsiya
A brief overview of a statistical method to estimate the probable maximum precipitation (PMP) is presented. This study addresses some issues associated with Hershfield's Km-value method to estimate PMP in China, which can be solved by the revised Hershfield's Km-value method. This new derivation makes it clear that the frequency factor Km is dependent on only two variables, the standardized variable, ϕm, the maximum deviation from the mean scaled by its standard deviation, and the sample size, n. It is found that there is a consistent relationship between Km and ϕm. Therefore, Km can be used to make a preliminary estimate of PMP under some conditions when sufficient rainfall data are available. The advantages and disadvantages of this revised Km-value method are also discussed here with a case study for the estimation of 24 h PMP in Hong Kong. The 24 h PMP estimate in Hong Kong based on the local rainfall data is approximately 1,753 mm.