ON THE CONTRIBUTION OF TROPICAL CYCLONES TO THE SOUTHEAST UNITED STATES HYDROLOGY

Tropical Cyclones (TCs) intensity and frequency are expected to be impacted by climate change. Despite their destructive potential, these phenomena, which can produce heavy precipitation, are also an important source of freshwater. Therefore any change in frequency, seasonal timing and intensity of TCs is expected to strongly impact the regional water cycle and consequently the freshwater availability and distribution. This is critical, due to the fact that freshwater resources in the US are under stress due to the population growth and economic development that increasingly create more demands from agricultural, municipal and industrial uses, resulting in frequent over-allocation of water resources. Here we first focus on investigating the contribution of TCs (season totals and event by event) to the SE US annual precipitation totals from 2002 to 2011 using NCEP Stage IV for precipitation estimates and USGS streamgage drainage basins as integrative unit. A water budget approach is then applied on these drainage basins to investigate the partitioning of TCs precipitation into surface runoff and groundwater system in the direct aftermath of major TCs. This framework will allow exploring the contribution of TCs to the recharge of groundwater reservoirs across different physiographic regions (mountains, coastal and alluvial plains) versus the fraction that is quickly evacuated through the river network and surface runoff. This work will contribute to better understand the redistribution of TCs precipitation across the landscape and estimate what could be the impact of potential changes in TCs activity on the SE regional hydrology.