Hourly Precipitation Data Rainfall Event Statistics

Hourly Precipitation Data Rainfall Event Statistics is historical digital data set DSI-9651, archived at the National Climatic Data Center (NCDC). This historical data set is a set of statistics summarizing nationwide hourly precipitation data (HPD) from stations in the United States of America and Puerto Rico. The time period covered is 1948 through 1983. The expected use of DSI-9651 would be to provide parameters useful in estimation procedures for water budgets including infiltration, runoff, evaporation, and ground water recharge. A major application might be engineering estimates of pollutant transport. A past application has been to provide information necessary (Perrich, 1992) to satisfy the US EPA Storm Water Permitting Program under the National Pollution Discharge Elimination System. A total of 26 long-term monthly rainfall statistics was computed from HPD. These statistics are described in detail by Steurer and Nold (1986). Generally, the statistics included wet and dry day counts and storm frequencies, depths, intensities, and durations. Storm event statistics are to be applied to continuous-time stochastic modeling as described by Eagleson (1978). Wet versus dry day statistics are for application of discrete-time models as described by Richardson (1981) and Nicks (1975). To do the computations, software was developed at NCDC that read data from NCDC's Hourly Precipitation Data data set (DSI-3240). The software computed statistics for those stations that met a selection test: They must have at least ten years of data during the period 1948 to 1983. Any month of data that had more than 9 days of missing or undefined values, was excluded. This led to the selection of 3,225 stations for use in the computations. There are separate and combined statistics for periods of time in which astandard weighing rain gauge was used at a station, and for periods when a Fischer-Porter rain gauge was used.