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The Quality of Rainfall Estimation with the Polarimetric Wsr-88 D Radar as a Function of Range
| Content Provider | Semantic Scholar |
|---|---|
| Author | Giangrande, Scott E. Ryzhkov, Alexander V. |
| Copyright Year | 2003 |
| Abstract | Accurate rainfall estimates are vital for several hydrologic applications. The National Weather Service requires estimating rainfall at ranges up to 230 km from the radar. Rainfall estimates at large distance are especially important in regions with limited radar coverage. Having reliable rain estimates over large distances is also beneficial for validation of satellite observations since these are usually characterized by rather wide swaths. Increased distance from the radar is often associated with a degradation of accuracy among conventional R(Z) relations. Range-related errors may be significant, particularly during cold season events associated with low melting layers. Range dependence is also attributed to overshooting of precipitation, beam geometry such as beam broadening and filling, radar signal sensitivity losses, and drop size distribution (DSD) evolution in the vertical which can produce illuminated volume characteristics bearing little resemblance to the near-surface scatterers. While some studies discuss the quality of conventional radar rain measurements at large distances (e.g., Smith et al. 1996, Seo et al. 2000), the performance of polarimetric methods at distances greater than 100 km is not well investigated. With few exceptions, the majority of the dual-polarization S-band radar gauge comparisons were made for warm season precipitation and at distances less than 100 km. These validation studies have shown that at close distances from the radar (a) there is an improvement in rainfall estimation if a dual polarization radar is used and (b) polarimetric rainfall estimation techniques are more robust with respect to DSD variations than are conventional R(Z) relations. It is not clear if these advantages of dual polarization radar hold at larger distances from the radar. As part of the evolution and future enhancement of the WSR-88D, the National Severe Storms Laboratory recently upgraded the KOUN WSR-88D radar to include polarimetric capability. In this paper, we assess the quality of rainfall estimation for a broad range of distances. 108 Oklahoma Mesonet gauges are used to validate the results of radar rain measurements. These gauges are located at distances between 25 and 290 km from the KOUN radar. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://ams.confex.com/ams/pdfpapers/64220.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
