Status: this preprint was under review for the journal AMT. A revision for further review has not been submitted.
Exploring the potential of utilizing high resolution X-band radar for urban rainfall estimation
Wen-Yu Yang,Guang-Heng Ni,You-Cun Qi,Yang Hong,and Ting Sun
Abstract. X-band-radar-based quantitative precipitation estimation (QPE) system is increasingly gaining interest thanks to its strength in providing high spatial resolution rainfall information for urban hydrological applications. However, prior to such applications, a variety of errors associated with X-band radars are mandatory to be corrected. In general, X-band radar QPE systems are affected by two types of errors: 1) common errors (e.g. mis-calibration, beam blockage, attenuation, non-precipitation clutter, variations in the raindrop size distribution) and 2) “wind drift” errors resulting from non-vertical falling of raindrops. In this study, we first assess the impacts of different corrections of common error using a dataset consisting of one-year reflectivity observations collected at an X-band radar site and a distrometer along with rainfall observations in Beijing urban area. The common error corrections demonstrate promising improvements in the rainfall estimates, even though an underestimate of 24.6% by the radar QPE system in the total accumulated rainfall still exists as compared with gauge observations. The most significant improvement is realized by beam integration correction. The DSD-related corrections (i.e., convective–stratiform classification and local Z-R relationship) also lead to remarkable improvement and highlight the necessity of deriving the localized Z-R relationships for specific rainfall systems. The effectiveness of wind drift correction is then evaluated for a fast-moving case, whose results indicate both the total accumulation and the temporal characteristics of the rainfall estimates can be improved. In conclusion, considerable potential of X-band radar in high-resolution rainfall estimation can be realized by necessary error corrections.
How to cite. Yang, W.-Y., Ni, G.-H., Qi, Y.-C., Hong, Y., and Sun, T.: Exploring the potential of utilizing high resolution X-band radar for urban rainfall estimation, Atmos. Meas. Tech. Discuss. [preprint], https://doi.org/10.5194/amt-2016-388, in review, 2016.
Received: 25 Nov 2016 – Discussion started: 12 Dec 2016
Using a dataset consisting of one-year measurements by an X-band radar and distrometer, we found that error corrections greatly improve X-band-radar-based rainfall estimation. Specifically, the greatest improvement is realized by the beam integration. Derivation of localized Z-R relationships for specific rainfall systems is also of great importance. Moreover, wind drift correction improves quantitative estimates and temporal consistency.
Using a dataset consisting of one-year measurements by an X-band radar and distrometer, we found...