基于1979—2008年京津冀地区175个气象站的冰雹观测资料,应用气候趋势系数、倾向率、集中度和集中期,以及连续功率谱等方法,分析了京津冀地区及4个划分关键区冰雹发生的多时间尺度变化特征和变化趋势,并运用蒙特卡罗方法检验了气候趋势系数的显著性。结果表明：近30年该地区的冰雹有明显减少趋势,北部地区比南部地区减少幅度要大,山地区域比平原地区减少幅度大;基本上都存在2.0～2.5年的变化周期,该地区冰雹的发生具有准两年周期振荡的特征;南部平原冰雹发生的集中度最大,该区冰雹在年内发生时间最为集中;南部平原集中期较早,出现在6月初,其他几个关键区冰雹主要发生在6月底到7月初。应用气候要素累计距平曲线、Yamamoto方法进行了气候突变分析,结果表明京津冀地区冰雹在1993年发生了减少的突变,山地区域尤为显著。%Based on the daily hail data at 175 stations in Beijing,Tianjin and Hebei Province（BTH for short hereinafter） during 1979 to 2008,using climate trend coefficient,trend rate,concentration degree （CD）,concentration period（CP）,and continuous power spectrum,the multiple time-scale variation characteristics and trend variation of hail in BTH area are analyzed.It focuses on the four different key regions. Meanwhile,the significance of trend coefficient is tested by Monte Carlo scheme.The results show that the hail during last 30 years has increased obviously,the negative trend of hail is that reduction is larger in the northern areas than the southern areas,and larger in the mountain regions than the plain regions; there are 2.0—2.5 year periodic oscillations for interannual variations in all key regions,the interannual change of the occurring frequency of hail is characteristic of quasi-biennial oscillation（QBO）;The hail-concentration degree（HCD） in the southern area was the biggest,indicating that the time when hail occurred in this key region was relatively concentrated;The hail-concentration period（HCP） in all regions except southern area being in pentad 31（about early June）,was pentads 36-37,indicating that hail mainly occurred from late June to early July.Analysis on abrupt climate change using accumulated anomaly method and Yamamoto method shows that an abrupt decreasing occurred in 1993,especially in mountain regions.
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