南岳高山站风对赣北暴雨的指示作用

利用2005—2013年4—6月南岳站逐时风场观测资料、常规探空资料、自动站雨量资料及NCEP/NCAR全球再分析资料（2.5°×2.5°）,分析南岳站气象要素对对流层低层环流场的代表性以及该站风演变对汛期赣北暴雨的指示作用。主要结果是：（1）南岳站逐日风与NCEP资料850 h Pa风场相关系数最大中心（0.72~0.78）位于南岳山附近,该站风对当地850 h Pa风具有较好的代表性;该站风与NCEP资料850 h Pa风场的平均相关系数（0.75）较之其与925 h Pa风场的平均相关系数（0.68）高,证明该站风与当地850 h Pa风场特征更接近。（2）探空站与南岳站距离越近（远）,其各种气象要素的相关性越好（差）,进一步证实南岳站气象要素对当地850 h Pa相应要素具有较好的代表性。（3）汛期,当满足＂南岳山西南风＋切变指标＂时,未来24 h赣北出现局部或区域暴雨的概率达89.8%;当满足＂南岳山西南风＋切变指标＂时,且当日20时至次日08时南岳站由非西南风转为西南风或由弱西南风转为较强西南风后,可预报未来4~18 h（平均10 h）赣北开始产生暴雨;赣北出现暴雨后,当南岳站由持续西南风转为偏北风后1~3 h强降水区开始逐步南压东移,6~17 h（平均10.5 h）后强降水区南压或东移出赣北。

Indicative analysis of wind variations at the Nanyue Mountain Station to heavy rain over Northern Jiangxi

Based on hourly observations of wind field at Nanyue Mountain station between April and June from 2005 to 2013, conventional sounding data, rainfall data from automatic weather station and 2.5 °× 2.5° global reanalysis data from NCEP/NCAR, we analyze the representativeness of data collected at the Nanyue station to the atmospheric general circulation field in the lower troposphere and the indicative function of the evolution characteristics of wind field at the station to heavy rain over Northern Jiangxi in flood season. Main results are as follows. （1） The most significant correlation （correlation coefficient 0.72-0.78） between daily wind at the Nanyue station and daily 850 hPa wind field from NCEP, locates around Nanyue Mountain, in which the wind has a good indicative function to the local wind field at 850 hPa. The average correlation coefficient （0.75） is higher between wind at the station and 850 hPa wind field from NCEP than that （0.68） between wind at the station and 925 hPa wind field from NCEP, which proves that wind at the station is much closer to local wind field at 850 hPa. （2） The closer （farther） the distance between a sounding station and the Nanyue station is, the better （worse） the correlation of various meteorological elements between them is, which further confirms the above conclusions. （3） In flood season, when there is southwest wind at Nanyue station and corresponding shear index, the probability of heavy rain over Northern Jiangxi within 24 h reaches 89.8%. When the above criteria are met and after the wind at the Nanyue station changes from other direction （weak southwest wind） to southwest direction （strong southwest wind） from 20：00 BT of the current day to 08：00 BT next day, we can forecast heavy rain over Northern Jiangxi within 4-18 h （10 hours on average）. After the occurrence of heavy rain over Northern Jiangxi, the severe precipitation area starts to shift southwards and moves eastwards after 1-3 h when wind at the Nanyue statio