Contents lists available at ScienceDirect Atmospheric Research journal homepage: www.elsevier.com/locate/atmosres Cross-evaluation of reflectivity from the space-borne precipitation radar and multi-type ground-based weather radar network in China Lingzhi Zhong a,⁎ , Rongfang Yang b , Yixin Wen c , Lin Chen d,⁎ , Yabin Gou e , Ruiyi Li f , Qing Zhou f , Yang Hong g,h a Chinese Academy of Meteorology and Science, China b Public Weather Service Center, Hebei Meteorological Bureau, China c Cooperative Institute for Mesoscale Meteorological Studies, University of Oklahoma, Norman, OK, United States d National Satellite Meteorology Center, China Meteorological Administration, Beijing, China e Hangzhou Meteorological Bureau, Hangzhou, China f Meteorological Observation Center, China Meteorological Administration, Beijing, China g State Key Laboratory of Hydro science and Engineering, Tsinghua University, Beijing, China h School of Civil Engineering and Environmental Sciences, University of Oklahoma, Norman, United States ABSTRACT China operational weather radar network consists of more than 200 ground-based radars (GR(s)). The lack of unified calibrators often result in poor mosaic products as well as its limitation in radar data assimilation in numerical models. In this study, radar reflectivity and precipitation vertical structures observed from space- borne TRMM (Tropical Rainfall Measurement Mission) PR (precipitation radar) and GRs are volumetrically matched and cross-evaluated. It is found that observation of GRs is basically consistent with that of PR. For their overlapping scanning regions, the GRs are often affected by the beam blockage for complex terrain. The statistics show the better agreement among S band A type (SA) radars, S band B type (SB) radars and PR, as well as poor performance of S band C type (SC) radars. The reflectivity offsets between GRs and PR depend on the reflectivity magnitudes: They are positive for weak precipitation and negative for middle and heavy precipitation, re- spectively. Although the GRs are quite consistent with PR for large sample, an individual GR has its own fluc- tuated biases monthly. When the sample number is small, the bias statistics may be determined by a single bad GR in a group. Results from this study shed lights that the space-borne precipitation radars could be used to quantitatively calibrate systematic bias existing in different GRs in order to improve the consistency of ground- based weather radar network across China, and also bears the promise to provide a robust reference even form a space and ground constellation network for the dual-frequency precipitation radars onboard the satellites an- ticipated in the near future. 1. Introduction Weather radars can help us to understand and monitor severe weather in flood seasons. The weather radar platform mainly includes ground-based radars (hereafter GR(s)), airborne radars, and space- borne radars, all with advantages and disadvantages. Ground-based radars are easily built, especially on flat terrain. Airborne weather ra- dars can be easily hung from aircraft in order to look through pre- cipitation and acquire the structure and characteristics of cloud and precipitation due to its small volume and light weight. Space-borne weather radars can obtain much more information regarding global cloud and precipitation distributions over a wide range, especially in areas where ground-based and airborne weather radars are unable to detect. China started construction of the ‘China New Generation Doppler Weather Radar (CINRAD)’ network in 1998, and about 200 radars, consisting of 10-cm (S-band, including A-type (SA), B-type (SB), and C-type (SC)) and 5-cm (C-band) wavelengths have been utilized in operational observations. The S-band CINRAD radars are much like the WSR-88D (Weather Surveillance Radar, 1988, Doppler) units used in the USA, i.e., with approximately a 1° beam width by 1-km range re- solution and a volume scan sampling frequency of about 6 min. Each volume scan consists of nine sweeps, with elevation angles ranging from 0.5° (base scan) to 19°. There has been a vast amount of references to the application of http://dx.doi.org/10.1016/j.atmosres.2017.06.016 Received 6 December 2016; Received in revised form 20 April 2017; Accepted 13 June 2017 ⁎ Corresponding authors. E-mail addresses: zhonglz@camscma.cn (L. Zhong), chenlin@cma.gov.cn (L. Chen). Atmospheric Research 196 (2017) 200–210 Available online 15 June 2017 0169-8095/ © 2017 Elsevier B.V. All rights reserved. MARK