Development of a Climatology of Precipitation System Organization in North Carolina to Improve Climate Precipitation Forecasts

Since no major rivers flow into the State of North Carolina, precipitation falling within the state is the primary natural source of water to replenish that region's rivers, soils, and groundwater reservoirs. As climate and population pressures change, water management and sustainability policies in North Carolina will be increasingly dependent on an improved understanding of precipitation variability in that region.

Intellectual merit:

The premise of this study is that a novel climatology of precipitation system mode of delivery in North Carolina, developed with newly available high resolution precipitation and three-dimensional radar reflectivity datasets, will lead to improved regional climate and hydrological forecasts. Mode of delivery refers to the spatial, temporal and water phase characteristics of a precipitation system. Examples of mode of delivery that occur in North Carolina within various synoptic regimes include short duration and spatially heterogeneous convective cells, large mesoscale convective systems, widespread long-lasting frontal precipitation, tropical cyclones, and winter precipitation. Each mode of delivery may produce similar time-averaged precipitation totals, but have very different climate and hydrological impacts. A mode of delivery climatology will provide a unique tool for process-based downscaling of climate simulations to the watershed scale.

The project will consist of three main parts, as follows. 1) The first part aims to develop and implement a methodology to identify the distinct mode of delivery of rainfall, which will be applied to five years (2006-2010) of the National Mosaic and Multi-sensor Quantitative Precipitation Estimation (NMQ) radar reflectivity and precipitation datasets. We will leverage a partnership between the University of North Carolina Renaissance Computing Institute, and the National Climate Data Center to analyze regional NMQ data sets constructed for this project using data-mining techniques for computational efficiency. 2) The second part of the project will examine the relationship between mode of delivery of rainfall and the dominant regimes of the synoptic-scale flow and intraseasonal-to-interannual climate variability. 3) The third part of this study will test the hypothesis that for seasonal time scales and regional spatial scales, the mode of delivery of rainfall provides a basis for the process-based downscaling (tied to different synoptic regimes) of precipitation in reanalysis products and climate model simulations.

Broader impacts:

The project will have significant implications for climate prediction for a region (North Carolina) where those connections have not been fully explored. The climatology will result in improvements to regional climate model forecasting and with future applications to improve hydrological simulations on the watershed scale. The project also include significant benefits to NOAA and NASA hydrological research and operational programs (NOAA Hydrometeorological Testbed-Southeast and NASA Global Precipitation Mission). The project will provide a platform for undergraduate and graduate student research and training. Project results and outreach will benefit the agricultural communities in eastern North Carolina, which have been historically underserved with respect to educational and economic opportunities, while at the same time have been vulnerable to severe weather and flood-related hazards. The success of this project will improve a process-based downscaling of climate model precipitation estimates to the regional and watershed scale.