本文利用舟山地区的雷暴观测资料、闪电定位资料、MICAPS(meteorology information comprehensive analysis process system)常规气象资料等,对舟山绿色石化基地地区2017—2021年雷暴天气时空分布特征及分类特征进行统计分析。结果表明:...本文利用舟山地区的雷暴观测资料、闪电定位资料、MICAPS(meteorology information comprehensive analysis process system)常规气象资料等,对舟山绿色石化基地地区2017—2021年雷暴天气时空分布特征及分类特征进行统计分析。结果表明:2017—2021年该地区年均地闪密度约为1.9~2.1次/km^(2)·a;雷暴天气在2019年后逐年增加。月雷暴分布呈双峰型,8月雷暴最多,月均雷暴日为7.2 d。5年内夏季发生雷暴的次数占全年的58%。从热动力学结构特征将该地区的雷暴天气分为5类:准正压类、斜压锋生类、暖平流强迫类、冷平流强迫类和高架雷暴类,依次占比51%、19%、16%、10%和4%;夏季以准正压类占主导,春季多为斜压锋生类。通过对NCEP 1°×1°物理量再分析场对雷暴过程的指示性进行统计分析,结果显示:CAPE、K指数、LI指数、PWAT是判断夏、秋两季出现强对流的敏感性指标,而春季仅有K指数有较好的指示意义;T(850~500 hPa)在23~24℃,是判断是否出现雷暴的有利指标;高低空垂直风切变(春季:14.61 s^(-1)、夏季:6.89 s^(-1)、秋季:8.30 s^(-1))是指导不同季节是否发生雷暴最有区分度的判据。展开更多
Based on various statistical indices,the abilities of multi-generation reanalyses,namely the NCEP/NCAR Reanalysis 1(R1),the NCEP-DOE Reanalysis 2(R2)and the NCEP Climate Forecast System Reanalysis(CFSR),to reproduce t...Based on various statistical indices,the abilities of multi-generation reanalyses,namely the NCEP/NCAR Reanalysis 1(R1),the NCEP-DOE Reanalysis 2(R2)and the NCEP Climate Forecast System Reanalysis(CFSR),to reproduce the spatiotemporal characteristics of precipitation over Zhejiang Province are comprehensively compared.The mean absolute bias percentages for three reanalyses are 20%(R1),10%(R2)and 37%(CFSR).R2(R1)gives the best(worst)general depiction of the spatial characteristics of the observed precipitation climatology,whereas a significant wet bias is noticed in the CFSR.All reanalyses reasonably reproduce the interannual variability with the correlation coefficients of 0.72(R1),0.72(R2)and 0.84(CFSR).All reanalyses well represent the first two modes of the observed precipitation through Empirical Orthogonal Function analysis,with CFSR giving the best capture of the principal components.The root-mean-square error(RMSE)is the largest(smallest)in the CFSR(R2).The large RMSE of CFSR in summer(especially in June)contributes mostly to its systematic wet bias.After 2001,the wet bias of CFSR substantially weakens,probably attributed to increasing observations assimilated in the CFSR.On a monthly basis,the percentage of neutral bias cases are similar for all reanalyses,while the ratio of positive(negative)bias cases for CFSR is distinctly larger(smaller)than that of R1 and R2.The proportions of negative bias cases for R1 and R2 begin to increase after 2001 while keeping stable for CFSR.On a daily basis,all reanalyses give good performances of reproducing light rain;however,the reflection of moderate rain and heavier rain by the CFSR is better than R1 and R2.Overall,despite being a third-generation reanalysis product,the CRSR does not exhibit comprehensive superiorities over R1 and R2 in all aspects on a regional scale.展开更多
基金Zhejiang Province Basic Public Welfare Program(LGF19D050001)Key R&D Program of Zhejiang Province(2021C02036)+2 种基金China Meteorological Administration Special Fund for Forecasters(CMAYBY2019-048)National Key R&D Program of China(2018YFC1505601)Key Program of Zhejiang Meteorological Bureau(2020ZD14)。
文摘Based on various statistical indices,the abilities of multi-generation reanalyses,namely the NCEP/NCAR Reanalysis 1(R1),the NCEP-DOE Reanalysis 2(R2)and the NCEP Climate Forecast System Reanalysis(CFSR),to reproduce the spatiotemporal characteristics of precipitation over Zhejiang Province are comprehensively compared.The mean absolute bias percentages for three reanalyses are 20%(R1),10%(R2)and 37%(CFSR).R2(R1)gives the best(worst)general depiction of the spatial characteristics of the observed precipitation climatology,whereas a significant wet bias is noticed in the CFSR.All reanalyses reasonably reproduce the interannual variability with the correlation coefficients of 0.72(R1),0.72(R2)and 0.84(CFSR).All reanalyses well represent the first two modes of the observed precipitation through Empirical Orthogonal Function analysis,with CFSR giving the best capture of the principal components.The root-mean-square error(RMSE)is the largest(smallest)in the CFSR(R2).The large RMSE of CFSR in summer(especially in June)contributes mostly to its systematic wet bias.After 2001,the wet bias of CFSR substantially weakens,probably attributed to increasing observations assimilated in the CFSR.On a monthly basis,the percentage of neutral bias cases are similar for all reanalyses,while the ratio of positive(negative)bias cases for CFSR is distinctly larger(smaller)than that of R1 and R2.The proportions of negative bias cases for R1 and R2 begin to increase after 2001 while keeping stable for CFSR.On a daily basis,all reanalyses give good performances of reproducing light rain;however,the reflection of moderate rain and heavier rain by the CFSR is better than R1 and R2.Overall,despite being a third-generation reanalysis product,the CRSR does not exhibit comprehensive superiorities over R1 and R2 in all aspects on a regional scale.
