近几十年北半球孤立子阻塞和偶极子阻塞活动的对比研究

对1958—1997年美国NCEP逐日高度场再分析资料进行低通滤波,利用滤波后的资料统计分析了北半球的孤立子阻塞和偶极子阻塞的地理位置分布、年际变化、季节特点等,又对大西洋、太平洋和乌拉尔山地区3个阻塞多发地的孤立子阻塞和偶极子阻塞活动特点进行比较,发现偶极子阻塞的纬度主要活动带比孤立子阻塞偏北5~10个纬度;孤立子阻塞主要在大西洋地区和乌拉尔山区活动,偶极子阻塞主要发生在太平洋地区,无论孤立阻塞还是偶极子阻塞在60°W~140°W(即美洲地区)都是最少的;孤立子阻塞和偶极子阻塞都有明显季节变化,孤立子阻塞活动的纬度峰值区是春季、秋季和冬季一致,夏季最偏北;偶极子阻塞活动的纬度峰值区是夏秋季位置最偏南,冬季发生区最偏北。孤立子阻塞经度的季节性要比偶极子阻塞更显著,但夏季经度位置最偏东和冬季最偏西的特点一样;太平洋地区无论孤立子阻塞还是偶极子阻塞活动纬度区都比大西洋和乌拉尔山地区偏北5~10个纬度;孤立子阻塞和偶极子阻塞天数都是冬季最多,春季次之,孤立子阻塞天数夏、秋数量相差不多,秋季稍多,偶极子阻塞秋季最少;孤立子阻塞和偶极子阻塞都有逐年减少的趋势,两者具有相反的年际变化等一些有意义的结果。

A Comparative Study of Soliton and Dipole Blockings in the Northern Hemisphere

The geographical position and interannual variation and seasonal variation of soliton and dipole blockings in the Northern Hemisphere are statistical studied by using the daily NCAR-NECP reanalysis data during 1958 to 1997 which be filtered.Dipole blocking is 5~10 degree more north than soliton blocking in the Atlantic,Pacific and Ural mountain.Soliton blocking generally occurs in the Atlantic and the Ural mountains,but dipole blocking mainly occurs in the Pacific.These blocking patterns are minimum in 60 W...