DOI: 10.1016/j.atmosres.2017.10.020
Scopus记录号: 2-s2.0-85033497214
论文题名: Intercomparison of attenuation correction algorithms for single-polarized X-band radars
作者: Lengfeld K. ; Berenguer M. ; Sempere Torres D.
刊名: Atmospheric Research
ISSN: 1698095
出版年: 2018
卷: 201 起始页码: 116
结束页码: 132
语种: 英语
英文关键词: Attenuation correction
; Single-polarization
; X-band radar
Scopus关键词: Calibration
; Meteorological radar
; Microwave antennas
; Radar
; Radar systems
; Reflection
; Attenuation correction
; Long term performance
; Precipitation events
; Single polarization
; Specific attenuation
; Statistical relations
; Temporal and spatial
; X-band Radars
; Radar measurement
; algorithm
; correction
; mountain region
; observational method
; polarization
; precipitation (climatology)
; radar
; spatial resolution
英文摘要: Attenuation due to liquid water is one of the largest uncertainties in radar observations. The effects of attenuation are generally inversely proportional to the wavelength, i.e. observations from X-band radars are more affected by attenuation than those from C- or S-band systems. On the other hand, X-band radars can measure precipitation fields in higher temporal and spatial resolution and are more mobile and easier to install due to smaller antennas. A first algorithm for attenuation correction in single-polarized systems was proposed by Hitschfeld and Bordan (1954) (HB), but it gets unstable in case of small errors (e.g. in the radar calibration) and strong attenuation. Therefore, methods have been developed that restrict attenuation correction to keep the algorithm stable, using e.g. surface echoes (for space-borne radars) and mountain returns (for ground radars) as a final value (FV), or adjustment of the radar constant (C) or the coefficient α. In the absence of mountain returns, measurements from C- or S-band radars can be used to constrain the correction. All these methods are based on the statistical relation between reflectivity and specific attenuation. Another way to correct for attenuation in X-band radar observations is to use additional information from less attenuated radar systems, e.g. the ratio between X-band and C- or S-band radar measurements. Lengfeld et al. (2016) proposed such a method based isotonic regression of the ratio between X- and C-band radar observations along the radar beam. This study presents a comparison of the original HB algorithm and three algorithms based on the statistical relation between reflectivity and specific attenuation as well as two methods implementing additional information of C-band radar measurements. Their performance in two precipitation events (one mainly convective and the other one stratiform) shows that a restriction of the HB is necessary to avoid instabilities. A comparison with vertically pointing micro rain radars (MRR) reveals good performance of two of the methods based in the statistical k-Z-relation: FV and α. The C algorithm seems to be more sensitive to differences in calibration of the two systems and requires additional information from C- or S-band radars. Furthermore, a study of five months of radar observations examines the long-term performance of each algorithm. From this study conclusions can be drawn that using additional information from less attenuated radar systems lead to best results. The two algorithms that use this additional information eliminate the bias caused by attenuation and preserve the agreement with MRR observations. © 2017 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/108996
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Deutscher Wetterdienst, Offenbach am Main, Germany; Centre de Recerca Aplicada en Hidrometeorologia, Universitat Politécnica de Catalunya, Barcelona, Spain
Recommended Citation:
Lengfeld K.,Berenguer M.,Sempere Torres D.. Intercomparison of attenuation correction algorithms for single-polarized X-band radars[J]. Atmospheric Research,2018-01-01,201