A GIS-based analysis of precipitation organization, topography, and land use in North Carolina using the Multi-Sensor Precipitation Estimation (MPE) product

A climatology of precipitation organization is developed for the Southeast United States and analyzed for North Carolina in a GIS framework. This climatology is created using five years (2009-2013) of daily-averaged data from the NOAA high-resolution multi-sensor precipitation estimation (MPE) dataset, specifically the radar-based QPE and the mosaic reflectivity. The analysis associates precipitation at each pixel with storm organization (mesoscale convective system (MCS), isolated convective cell, or tropical cyclone) and with the water phase (snow or rain). While the long-term averaged precipitation totals of these systems may be similar, their hydrological and climatological impacts are very different, especially at a local scale. The classification of these “modes of delivery” in the current precipitation climatology will provide information beyond standard precipitation climatologies that will benefit a range of hydrological and climatological applications. This study will take advantage of a geographic information system (GIS) framework to examine the precipitation organization climatology in the context of topography and land use on a regional to local scale, with a focus on North Carolina. We will present seasonal and annual composites of precipitation and duration of MCSs and isolated convective cells across three regions of North Carolina: the western mountains, the central Piedmont, and the eastern coastal plain. The data will be ingested into ArcGIS allowing for a study of the connection between precipitation organization and land surface properties. We will employ a state-wide geographically weighted regression (GWR) to analyze the relationship between precipitation organization and elevation. While orographic effects are well known in the mountains, the connection between precipitation organization and other land surface properties (land use, urban regions, and coastal geography) are less known. We will look at precipitation anomalies at local scales to determine whether there is precipitation enhancement downwind of urban centers. Composites of precipitation organization will also provide information about the seasonal and geographic variability of precipitation systems, such as the coastal sea breeze or northwest flow snow events. We will illustrate these relationships with case study analyses of several extreme events.