The NEXRAD program has recently upgraded the WSR-88D network observational capability with dual polarization (DP). In this study, DP quantitative precipitation estimates (QPEs) provided by the current version of the NWS system are evaluated using a dense rain gauge network and two other single-polarization (SP) rainfall products. The analyses are performed for the period and spatial domain of the Iowa Flood Studies (IFloodS) campaign. It is demonstrated that the current version (2014) of QPE from DP is not superior to that from SP mainly because DP QPE equations introduce larger bias than the conventional rainfall- reflectivity [i.e., R(Z)] relationship for some hydrometeor types. Moreover, since the QPE algorithm is based on hydrometeor type, abrupt transitions in the phase of hydrometeors introduce errors in QPE with surprising variation in space that cannot be easily corrected using rain gauge data. In addition, the propagation of QPE uncertainties across multiple hydrological scales is investigated using a diagnostic framework. The proposed method allows us to quantify QPE uncertainties at hydrologically relevant scales and provides information for the evaluation of hydrological studies forced by these rainfall datasets.
L. K. Cunha et al., "NEXRAD NWS Polarimetric Precipitation Product Evaluation For IFloodS," Journal of Hydrometeorology, vol. 16, no. 4, pp. 1676 - 1699, American Meteorological Society, Jan 2015.
The definitive version is available at https://doi.org/10.1175/JHM-D-14-0148.1
Civil, Architectural and Environmental Engineering
Keywords and Phrases
Field experiments; Flood events; Hydrologic models; Precipitation; Radars/Radar observations; Rainfall
International Standard Serial Number (ISSN)
Article - Journal
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01 Jan 2015