摘要
天气雷达以较高的时空分辨率实时探测大气中的降水过程,在中小尺度降水监测中具有无可替代的优势。相比雨量计,用雷达估测降水具有明显的优势,但雷达资料的质量影响着降水估测的准确度。因此,应当进行雷达资料质量控制,以便获得准确的降水估测。
为了减小非降水回波及零度层亮带对雷达降水估测的影响,本文首先利用雷达反射率因子的水平结构和垂直梯度特征对基数据进行质量控制,识别出降水回波和非降水回波,消除低仰角非降水回波的影响。在此基础上对降水回波进行均匀型和对流型识别。利用区域分层平均法建立层状云降水回波反射率因子的垂直廓线VPR,采用自动识别技术识别零度层亮带平均高度及厚度,并对其进行抑制。经过亮带订正后的VPR在融化层高度的显著弯曲特征消失,PPI及VCS上高值区被抑制。
雷达反射率因子数据经过订正之后,利用扩展的交叉相关追踪技术计算得到环境风矢量场,作为回波运动外推的依据。利用Z-I关系,得到基于雷达估测的小时降雨量。地面实际雨量和预测雨量的对比分析表明：0-10mm雨量预测值与实际值吻合度相对较高,雷达估测雨量大于实际雨量；10-20mm和20mm雨量大值区,估测值明显偏低于实际值,相关性不好。以地面雨量计测值为标准评估外推降雨量的结果表明,混合云降水的评估指标优于对流云和层状云的评估指标,外推小时降水量与实况有较好的相关性,相关系数达0.6737。雨量小的区域预报精度较高；随着雨量的增大,外推预报的可靠性下降。因为雷达测量降雨量的基础是Z-I关系,所以,利用质量控制后的回波强度作外推参量,进行降水临近预报有一定的指示意义。
The weather radar has important significance in disastrous precipitation measurement of meso-microscale with high space-time resolution.Compared to raingauges, radar rainfall estimation had obvious advantages, but the quality of radar data have impact on the accuracy of rainfall estimation. Therefore, the quality control of radar data should be taken in order to obtain more accurate rainfall estimattion.
For the purpose of decreasing the effect of non-precipitation echoes and bright band on surface rainfall estimation, Radar reflectivity three-dimensional structure characteristic was presented to distinguish precipitation and non-precipitaion echoes removed afterwards,and then the stratiform and convective clouds were distinguished respectively from precipitation echoes. The VPR of stratiform clouds were constructed by averaging the layered reflectivies at near range to identify the height and depth of bright band. Both the curvature feature of VPR and the high area of echoes on PPI and VCS disappeared after the bright band reflectivities were corrected.
On the base of quality control of radar reflectivity factor, TREC vector field was calculated by using extend corrected (Tracking Radar Echo by Correlations) TREC technique to extrapolate radar reflectivity factors and obtain extrapolative hourly rainfall with the corresponding Z-I relationship. The comparative analysis between predicted values and actual values show that the predicted values overestimated and were still closest to the actual value in 0-10mm,,and the ruslts were opposite when predicted values were above 10mm. Then the raingauge data were used to evaluate the accuracy of hourly rainfall. Result show that precision evaluation index of mixed clouds were better than that of stratiform and convective clouds, the extrapolative hourly rainfall were closer to raingauge data and the correlation coefficient reaches 0.6737. The forecast accuracy of relatively small thershlods were much better than that of larger values. Because the radar rainfall estimation was based on the relationship between Z and I, using radar echo after quality control as the extrapolation parameter has certain indication to precipitation nowcasting.
引文
[1]Pierce C.E., Hardaker P.J.,Collier C.G.,et al.A system for generating automated nowcasts of convective precipitation.Meteorological Applications,2000,7:341-360
[2]Joss J, Waldvogel A.Precipitation Measurement and Hydrology//Atlas D.Radar in Meteorology:Battan Memorial and 40th Anniversary,1990:577-606
[3]Harrison D L, Driscoll S J D, Kitchen M.Improving precipitation estimates from weather radar using quality control and correction techniques.Meteoro Appl,2000,7(2):135-144
[4]Vignal B, Andrieu H, Creutin J D. Identification of vertical profiles of reflectivity from volume scan radar data. J Appl Meteor,1999,38:1214-1228
[5]Kitchen M, Brown R, Davies A G. Real-time correction of weather radar data for the effects of bright band, range and orographic growth in widespread precipitation. Q J R Meteorol Soc,1994,130:1231-1254
[6]Joss J, Lee R. The application of radar-gauge comparisons to operational precipitation profile corrections. J Appl Meteor,1995,34:2612-2630
[7]Andreu H, Creutin J D. Identification of vertidal profiles of radar reflectivity for hydrological applicati-ons using an inverse method.Partl:Formulation.J Appl Meteor,1995, 34:225-239
[8]Smyth T J,Illingworth A J. Radar estimates of rainfall rates at the ground in bright band and non-bright ban events. Q J R Meteorl Soc,1998,124:2417-2434
[9]Smith C J.The reduction of errors caused by bright bands in quantitative rainfall measurements made using radar.J Atmos Oceanic Technol,1986,3:129-141
[10]Cheng M,C G Collier.An objective method for recognizing and partially correcting brightband error in radar images.J Appl Meteor,1993.32:1142-1149
[11]Fabry F,I Zawadzki.Long-term radar observations of the melting layer of precipitation and their interpr-Etation J Atmos Sci,1995,52:838-851
[12]Sanchez-Diezma R,I Zawadzki, D Sempere-Torres.Identification of the bright band through the ana-lysis of volumetric radar data.J Geophys Res,2000,105(D2):2225-2236
[13]White A B, D J Gottas, E T Strem, et al.An automated brightband height detection algorithm for use with Doppler radar spectral moments.J Atmos Oceanic Technol,2002,19:687-697
[14]Gourley J,C Calvert.Automated detection of the bright band using WSR-88D data.Wea Forecasting,2003,18:588-599
[15]杜秉玉,高志球.雷达反射率因子垂直廓线研究和多种遥感资料综合估计降水.南京气象学院学报,1998,12(4)：729-736
[16]杨凡,顾松山,黄兴友,等.利用雷达回波垂直廓线估测地物阻挡区域层状云降水的技术研究.南京气象学院学报,2009,32(1)：145-150
[17]史锐,程明虎.多普勒雷达实时反射率因子垂直廓线观测研.气象,2005,31(9)：39-43
[18]陈明轩,高峰.利用一种自动识别算法移除天气雷达反射率因子中的亮带.应用气象学报,2006,17(2)：207-215
[19]曹俊武,刘黎平,陈晓辉,等.3836C波段双线偏振多普勒雷达及其在一次降水过程中的应用研究.应用气象学报,2006,17(2)：192-200
[20]吴翠红,万玉发,吴涛,等.雷达回波垂直廓线及其生成方法.应用气象学报,2006,17(2)：232-239
[21]肖艳姣,刘黎平,李中华,等.雷达反射率因子数据中的亮带自动识别和抑制.高原气象,2010,29(1)：197-205
[22]张乐坚,程明虎,陶岚.CINRAD-SA/SB零度层亮带识别方法.应用气象学报,2010,21(2)：171-179
[23]梁丰,陈明轩,王玉彬.近两届奥运会气象服务保障综述.气象,2002,28(10)：3-8
[24]Eilts M.D., Johnson J.T., Mitchell E.D., et al.Severe weather warning decision support system.18th Conf.on Severe Local srorms,Amer.Meteor.Soc.,san Fransisco,CA,1996.536-540
[25]Dixon M, Wiener G.TITAN:Thunderstorm Identification, Tracking, Analysis, and Nowcasting-A Radar-Based Methodology.J.Atmos.Oceanic Tech.,1993,10 (6):785-797
[26]Mueller C., Saxen T, Roberts R., et al.NCAR Auto-Nowcast System. Wea.Forecasting, 2003,18 (4):545-561
[27]Joe P., Falla M., Rijin P.V., et al. Radar Data Processing for Severe Weather in the National Radar Project of Canda.21th Conf.SELS.,San Antonio,TX,AMS,2003.221-224
[28]Golding B.W.Nimrod:A system for generating automated very short range forecasts.Meterorol.Appl.,1998,5:1-16
[29]Browning,K.A.The FRONTIERS plan:A strategy for using radar and satellite imagery for very-short-range precipitation forecasting.The Meteorological Magazine,1979,108:161-184
[30]Webb R.M.,Treloar A.,Colquhoun J.,et al.Overview of Sydney Weather During the Forecast Demon-stration Project. AMS 30th Int. Conf. Radar Met., Munich, Germany, Amer. Meteor. Soc.,19-24 July,2001.503-505
[31]汤达章,赵清云.雷达跟踪回波运动方法的研究(1)—相关分析法的误差及其来源.南京气象学院学报,1988,11(1)：89-99
[32]汤达章,傅得胜,张亚萍.暴雨回波跟踪及临近预报初探.南京气象学院学报,1992,15(1)：66-71
[33]肖艳姣,汤达章,李中华.风暴的自动识别、跟踪与预报.南京气象学院学报,1998.21(2)：232-239
[34]杜秉玉,姚祖庆.上海地区强对流天气短时预报系统.南京气象学院学报,2000.,23(2)：242-250
[35]金鸿祥,杨金政.长江中游暴雨监测预报业务系统(MUTRONS)的设计和结构.气象,1994,20(8)：17-21
[36]徐双柱,项经魁,万玉发,等MYTRONS系统在暴雨临近预报和研究中的应用.气象,1994,20(8)：37-42
[37]黄伟健,黎守德,李炳华.从雷达回波的移动趋势预报短期的降雨情况.粤港澳中尺度天气预测分析会,深圳,1998年8月10-11日
[38]李炳华,黎守德.交叠雨带和辐合线上强对流的雷达观测分析.全国季风与暴雨科学讨论会.珠海季风雨暴雨学术研讨会,珠海,中国,2000年4月12日
[39]李炳华,林超英.临近预报在城市地质灾害中的应用.中国气象学会2003年年会学术报告(特邀报告),中国,北京,2003年12月8-10日
[40]黎守德,李炳华.[／J、涡旋]-1999及2000年暴雨验证及最新发展策略.第十五届粤港澳重要天气研讨会,中国,香港,2001年2月14-15日
[41]陈建宇,李炳华.临近预报在香港[山泥倾泻警告]中的应用.第十七届粤港澳气象科技研讨会报告,中国,澳门,2003年1月22-23日
[42]广州中心气象台.基于GRAPES的综合临近预报系统(雨燕GRAPES-SWIFT)项目简介.广东科技,2010,6(238)：110-111
[43]宗蓉,刘春云.雷达反射率数据质量控制方法初探.气象与环境学报,2009,25(2)：62-67
[1]张培昌,杜秉玉,戴铁丕,等.雷达气象学,第3版.北京：气象出版社,2005
[2]俞小鼎,姚秀萍,熊廷南,等.新一代天气雷达原理及应用讲义.北京：中国气象局培训中心科学技术培训部,2000.435
[3]Koistinen, J., Michelson D.B., Hohti H.,et al.Operational Measurement of Precipitation in Cold Climates. Springer monograph series "Physics of Earth and Space Enviroment", Meischner, P.(ed.),2003.337
[4]Kitchen M.,Jackson P.M.Weather radar performance at long range-simulated and observed. J. Appl. Meteor.,1993,32:975-985
[5]Anderson I.Measurement of 20-GHz transmission through a radome in rain, IEEE Trans. Antennas and Propagation, AP-23,1975.619-622
[6]Zawadzki I.,Fabry F.,Elia R. de, et al.On quantitative interpretation of radar measurements. Preprints 29th Intern.Conf.on Radar Meteorology,Amer.Met.Soc.,Boston,1999.784-786
[7]Blanchet B., Neuman A., Jacquet G., et al.Improvement of rainfall measurements due to accurate synchronization of raingauges and due to advection use in calibration, volume Cluckie I.D. and Collier C.G(eds). Hydrological applications of weather radar, Ellis Horwood,England,1991.213-218
[8]Fabay F., Bellon A., Duncan M.R., et al.High resolution rainfall measurements by radar for very small basins:the sampling prolem reexamined.J.Hydrol.,1994,161:415-428
[9]Hannesen R., Gysi H.An enhanced precipitation accumulation algorithm for radar data.In Proc.2nd European Conference on Radar in Meteorology and Hydrology (READ),Delft, Neverlands, Copernicus GmbH,2002
[10]Gray W.R., Seed A.W.The characterisation of orographic rainfall.Meteorol.Appl.,2000,7: 105-119
[11]Gunn R., Kinzer GD.The terminal velocity of fall for water droplets in stagnant air. J. Meteorol.,1949,6:243-248
[12]Kessler E.Kinematic effect of vertical drafts on precipitation near earth's surface. Mon. Weather Review.1987,115:2862-2864
[13]Lee A.C.L.The influence of vertical air velocity on the remote microwave measurement of rain. J. Atmos.Oceanic Tech.,1988,5:727-735
[14]Collier C.Applications of weather radar systems:a guide to uses of radar data in meteoro-logy and hydrology.2nd Edition, Praxis John Wiley & Sons Ltd.,1996.190
[15]Joss J., Waldvogel A.Precipitation measurement and hydrology, a review.Radar Meteoro-logy, D.Atlas, Ed.Boston, MA:American Meteorol.Soc,1990.577-606
[16]程明虎,刘黎平,张沛源,等.暴雨系统的多普勒雷达反演理论和方法.北京：气象出版社,2004.254
[17]杨洪平,万蓉,石燕,等.淮河流域“6.30”暴雨过程的三部雷达联合反演降水分析.见：中国气象学会水文气象学委员会编.气象科技创新与大气科学发展(7),北京：气象出版 社,2003.423
[18]姚学祥,徐晶.2003年淮河流域大水期间体积降水量的研究.气象学报,2004,62(6)：803-813
[19]Wilson J.W.,Crook N.A.,Muller C.K.,et al "Nowcasting thunderstorms:a status report". Bull. Amer. Meteor. Soc.,1998,79(10):2079-2099
[20]Berenguer M., Davila J.,Corral.,et al.Hydrological evaluation of a nowcasting thchnique applied to flood forecasting.Preprints 31th Conf.on Radar Meteorology, Seattle,Washington, Amer. Meteor. Soc,2003.708-709
[21]Rinehart R E, Garvey E T. Three dimensional storm motion detection by convectional weather radarNature,1978,273:287-289
[22]Austin G L,Bellon A.The use of digital weather radar records for short-term precipitation forecasting.Quart J Roy Meteorol Soc,1974,100:658-664.
[23]俞小鼎,姚秀萍,熊廷南,等.新一代天气雷达讲义(试用).中国气象局培训中心,2000.
[24]Muell C,Ssxen T, Roberts R,et al.NCAR Auto-nowcast system.Weather and Forecasting, 2003,18:545-561
[25]Li P W, Wong W K, Chan K Y, et al.SWIRLS-An Evolving Nowcsting System.Technical Note, No.100Hong Kong Observatory,2000.
[26]Browning K A, Collier C G, Larker P R, et al.On the forecasting of frontal rain using a weather radar n-etwork.Mon Wea Rev,1982,110:534-552
[27]Einfalt T, Denoeus T,Jaquet G. A radar rainfall forecasting method designed for hydrological purposes.J Hydrol,1990,114:229-244.
[28]Wolf D E,Hall D J, Endlich R M, Experiment in automatic cloud tracking using SMS-GOES data.J Appl Meteor,1977,16:1219-1230
[29]Thorpe A J, Miller M J, Moncrieff M W.Two-dimensional convection in nonconstant shear: A model of mid-latitude squall lines.Qualt J Roy Meteorl Soc,1982,108:739-762.
[30]Rotunno R J,Klemp J B,Weisman M L.A theory for strong,long-lived squall lines.J Atmos Sci,1984,45:463-485
[31]Weisman M L,Klemp J B, Rotunno R J.Sreucture and evolution of numerically simulated squall lines.J Atmos Sci,1988,45:1990-013
[1]张培昌,杜秉玉,戴铁丕,等.雷达气象学,第3版.北京：气象出版社,2005
[2]SteinerM, Smith JA.Use of three dimensional reflectivity structure for automated detection and removal of non-precipitating echoes in radar data[J].Journal of Alomospheric and Oceanic Technology,2002,19(5):-673-686.
[3]Kessinger C, Ellis S, Andel J V.The radar echo classifier:A fuzzy logic algorithm for the WSR-88D[R]. Preprints CD,3rd Conference on Artificial Intelligence Application to the Environmental Science, American Meteorological Society,2003.
[4]Zhang J, Wang S, Clarke B.WSR-88D reflectivity quality control using horizontal and vertical reflectivity structure [R]. Preprints for 11st Conference on Aviation, Range, and Aerospace Meteorology, American Meteorological Society,2004.
[5]Lakshmanan V,Hondl.k.,tumpf.G,et al.Quality control of WSR-88D data Preprints,31st Int Conf.on Radar Meterology,AMS,2003:522-525
[6]Lakshmanan V,Hondl.k.,tumpf.G,et al.Quality control of Weather radar data using texture features and a neural network.5th Int.ConfAdv in Patt Recogn, IEEE, Kolkota,2003
[7]刘黎平,吴林林,杨引明.基于模糊逻辑的分步式超折射地物回波识别方法的建立和效果分析.气象学报,2007,65(2)：253-256.
[8]王佑兵,万玉发.雷达体扫反射率场的自动质量控制.气象科技,2006,34(5)：616-617.
[9]宗蓉,刘春云.雷达反射率数据质量控制方法初探.气象与环境学报,2009,25(2)：62-67
[10]Zhang J, Langston C, Howard K.Bright band identification based on vertical profiles of reflectivity from the WSR-88D.J Atmos Oceanic Technol,2008,25:1859-1872
[11]吴翠红,万玉发,吴涛,等.雷达回波垂直廓线及其生成方法.应用气象学报,2006,17(2)：232-239
[12]Stewart R E. Deep 0℃ isot hermal lauers within precipitation bands over soughern Ontatio[J]. J Geophys Res,1984,89:2567-2572
[13]肖艳娇,刘黎平,李中华,等.雷达反射率因子数据中的亮带自动识别和抑制.高原气象,2010,29(1)：197-205
[1]冯业荣,曾沁,梁巧倩等.综合临近预报系统“雨燕”(GRAPES-SWIFT)的研究开发.第21届奥港澳气象科技研讨会,香港,2007年1月24-25日
[2]Tuttle J D, G B Foote.Determination of the boundary layer airflow from a single Doppler radar[J].J.Atmos.Ocean.Tech.,1990,7:218-232.
[3]庄薇,刘黎平,王楠.新疆地区一次对流性降水的三维中尺度风场研究.应用气象学报,2006,1(4)：444-451
[4]Seed A.W.A dynamic and spatial scaling approach toadvection forecasting.Journal of App Meteorology, Vol.42:381-388.
[5]Germann U., and I.Zawadzki,2002:Scale-dependence of the predictability of precipitation from continent al radar images.Part I:Description of the methodology. Mon. Wea. Rev.,130, 2859-2873.
[6]Marc Berenguer, Carles Corral, Rafael Sanchez-Diezma et al. Hydrolo-gical validation of a radar-based nowcasting technique.Journal of Hydrometeorology,2005.
[7]俞小鼎,姚秀萍,熊廷南等.新一代天气雷达原理与应用讲义.北京：中国气象局培训中心科学技术培训部,2000.435.
[8]Rinehart R E, Garvey E T.Three-dimensional storm motion detection by conventional weather radar. Nature,1978,273:287-289
[9]Byers,H.R.,Braham R.R.The Thunderstorm Project.U.S.Government Printing Office, Washington, D.c.1949.287
[10]Browning K.A.,Collier C.GNowcasting of precipitation systems, Rev.Geoghys.1989,27: 245-370
[11]Colle B.A., Westrick K.J., Mass C.F.Evaluation of MM5 and Eta-10 precipitation forecasts over the Pacific Northwest during the cool season.Wea.Forecasting,1999,14:137-154.
[1]欧阳首承,陈刚毅,林益.信息数字化与结构预测,第1版.北京：气象出版社,2009
