Characterization of precipitation features in the Southeastern United States using a multi-sensor approach – milestones for a longer term assessment of climate change impacts

The precipitation climatology of the Southeastern United States spans a very broad spectrum of precipitation regimes. A warm season that is characterized by isolated thunderstorms, mesoscale convective systems, and tropical cyclones, and a winter season characterized by widespread frontal rain, ice, and snowfall. Each of these types of precipitation system impacts regional hydrology in very different ways, and are associated with a large variety of natural hazards. The goal of this study is two fold. The first aspect of this study focused on the analysis of long term remotely sensed datasets in order to assess precipitation patterns and hydro-climatic extremes. Using thirteen years (1998-2010) of TRMM (Tropical Rainfall Measuring Mission) precipitation products (TRMM 2A25 and 3B42), we derived rainfall characteristic (yearly, seasonal, diurnal) at fine scales. The contribution of extreme events such as tropical cyclones was the object of particular attention. Results showed that tropical cyclones account for about 8-12% of the seasonal (June to November) precipitation budget and up to 15-20% for areas located near the coasts. The second aspect of this work proposes to include ground based precipitation estimates derived from the National Mosaic and Multi-Sensor Quantitative precipitation Estimates (NMQ/Q2). An inter-comparison of satellite and ground based precipitation estimates is provided for the years 2008-2009, with a particular attention to mountainous areas where precipitation estimates are less reliable. Finally, this work represents a first step toward a longer-term approach that proposes to derive trends in the evolution of precipitation patterns and assessment of climate change effects on precipitation.