The change in the characteristics of rainfall under global warming has been emphasized in many recent studies. Tropical cyclones (TCs) contribute to significant amounts of rainfall over short time periods and landfalling TCs have significant impacts on human life and the local economy. Many models project that TCs will become more intense with more heavy precipitation under global warming. This emphasizes the need to verify the veracity of the characteristics of precipitation in high resolution data sets which are more capable of capturing these changes than the low resolution ones.

To date there exist several high resolution precipitation data sets ranging from 1o daily to 0.25o 3 hourly resolution which have been created using a variety of methods. Recently, we at Cooperative Institute for Climate Studies (CICS) have developed an independent daily, 0.25o product using all available microwave sensors with a common retrieval scheme for the 1998 – 2007 (10 years in length) time period called CHOMPS – CICS High Resolution Optimally interpolated Microwave Precipitation from Satellites. Validation of CHOMPS data indicates that precipitation from this data set compares well with those from more established techniques such as the CMORPH, TMPA, PERSIANN, and GPCP 1dd data and observational gauge data on different temporal and spatial scales.

In this study we present, an intercomparison of the characteristics of TC associated precipitation among the above mentioned data sets. TC associated precipitation that will be presented here, includes cumulative probability density functions (PDFs) of rainfall amount and frequency of occurrence of rain events for the active hurricane period (June through November) over the US coastal southeast and gulf of Mexico regions and over a large oceanic domain in the North Atlantic. An initial study of the intensity based on TMPA data over the oceanic North Atlantic region indicates that cyclones from the North Atlantic account for 8% of rain events and 17% of the total rain. The fractional contribution of accumulated TC rain to total rain increases nearly linearly as a function of rain-rate over the North Atlantic. Characteristics of landfalling hurricanes over the continental US will be verified using gauge data. We will extend this to study to all landfalling cyclones over the eastern coasts of US and Gulf of Mexico. We expect the differences in PDF between the data sets to highlight differences in input data (satellites and gauges) and the merging techniques used to create the final high resolution precipitation products. This study will also highlight the extent to which the different data products can be used in the study of extremes.