北极区域海冰异常变化与华北夏季降水的年际关系及其年代际变化

【作者】 刘海文；

【导师】 郭品文；

【作者基本信息】 南京气象学院 ， 气象学， 2004， 硕士

【摘要】 选用英国Hadley气候研究中心的UK／GISST海冰面积指数资料集、NCEP／NCAR逐月再分析资料500Hpa位势高度场资料和中国160站降水资料，分析了冬季戴维斯海峡海冰面积变化与华北夏季降水年际关系及其年代际变化。结果表明： 冬季北极海冰面积有明显的年际、年代际变化特点，冬季北极海冰面积变化近50年来有趋势性减少特征。 冬季戴维斯海峡海冰面积与华北7月降水在年际变化尺度上有明显的反相关关系。冬季戴维斯海峡的海冰面积增多(少)，同年华北7月降水偏少(多)。冬季戴维斯海峡海冰是影响华北7月降水的“强信号”。 冬季戴维斯海峡海冰面积与华北夏季及7、8月降水年际关系有明显的年代际变化特征：其与夏季总降水的年际关系由1974年前较好的负相关在1974年后变差，与7月降水的年际关系由1974年前较好的负相关在1974年后变弱，与8月降水的年际关系由1974年前较好的负相关在1974年后变差；另一方面，其与中国160站夏季及7、8月降水的年际关系在1974年前后发生变化的主要特征是：与夏季总降水、7月、8月降水的年际关系由1974年前的相关系数分布呈“东西型”变为1974年后相关系数分布呈“-+-”的“南北型”。 冬季戴维斯海峡海冰面积和北半球夏季、7月500Hpa位势高度场年际关系的年代际变化主要是相关系数分布型的变化：1974年前，相关系数分布型呈一个自新地岛开始经巴尔喀什湖到日本海的“-+-”型，该型和同期华北降水的反相关较好；1974年后，相关系数分布型变为呈自乌拉尔山开始经贝加尔湖到河套的“+-”型，该型和同期华北降水相关差。1974年前，冬季戴维斯海峡海冰面积和北半球8月500Hpa位势高度场的相关系数呈一个自乌拉尔山开始到鄂霍次克海以北分布的“+-+”型，该型和8月华北降水的反相关较好；1974年后，相关在欧亚大陆地区变差，没有明显的相关型，冬季戴维斯海峡海冰面积和8月华北降水关系变差。更多还原

【Abstract】 The features of the interannual relationship between winter sea-ice extent of Davis strait and rainfall of North China and the interdecadal variability of its interannual relationship are analyzed by Using UK/GISST sea-ice data-set of Hadley , monthly 500Hpa height field of NCEP/NCAR reanalysis data and monthly rainfall data from 160 stations in China. The results are as follows:The extent of arctic sea-ice has apparent characteristics of interannual, interdecadal variability and decreasing trend during the last 50 years in winter.Winter sea-ice extent of Davis Strait which is strong information for July rainfall of North China is negatively correlated with July rainfall of North China. When winter sea-ice extent of Davis Strait increases(decreases), July rainfall of North China decreases(increases).The apparent characteristics of interdecadal variability of interannual relationship between winter sea-ice extent of Davis Strait and Summer, July and August rainfall of North China are: The strongly negative correlation between winter sea-ice extent of Davis Strait and Summer rainfall of North China turns into bad correlation. The strongly negative correlation between winter sea-ice extent of Davis Strait and July rainfall of North China turns into weaker correlation. The strongly negative correlation between winter sea-ice extent of Davis Strait and August rainfall of North China turns into bad correlation. All the turn-point year is around 1974. Another feature of interdecadal variability of interannual relationship between winter sea-ice extent of Davis Strait and Summer, July and August rainfall of 160 stations is that The interannual correlation pattern have changed from East-West pattern to "+-+" North -South pattern around 1974.The interdecadal characteristics of correlation distribution pattern of interannual relationship between winter sea-ice extent of Davis Strait and Summer, July 500hpa height of Northern hemisphere are: "-+-" pattern from the beginning of Novoya Zemlya island, by way of Balkhash lake to Japan sea which is strongly negatively correlated with the rainfall of North China at the same period before 1974and "+-" pattern from the beginning of Ural mountains ,by way of Bujr lake to Hetao basin which is badly correlated with the rainfall of North China at the same period after 1974. The interdecadal characteristics of correlation pattern of interannual relationship between winter sea-ice extent of Davis Strait and August 500hpa height of Northern hemisphere is "+-+"pattern from Ural Mountains to north of sea of Okhotsk which is strongly negatively correlated with the August rainfall of North China before 1974,and it has not apparent correlation pattern in Europe-Asia continent after 1974.更多还原