全球海气系统年际和年代际变化的时空特征分析  

TEMPORAL AND SPATIAL CHARACTERISTICS OF INTERANNUAL AND INTERDECADAL VARIATIONS IN THE GLOBAL OCEAN-ATMOSPHERE SYSTEM

作　　者：郭燕娟[1] 杨修群[1] 

机构地区：[1]南京大学大气科学系,南京210093

出　　处：《气象科学》2002年第2期127-138,共12页Journal of the Meteorological Sciences

基　　金：<国家重点基础研究发展规划>G1 9980 4 0 80 0项目;国家基金 4 0 0 75 0 1 7项目的共同资助

摘　　要：本文利用从 195 0 - 1998年共计 4 9年的马里兰 (Maryland)大学全球海洋同化分析资料和 NCEP全球大气再分析资料 ,分析了全球海气系统年际和年代际变化的主要时空特征 ,结果表明 :1)全球上层海洋年际变化的主要模态是位于热带太平洋的 ENSO模态 ,海洋年代际变化的最显著区域为南半球高纬度及中纬度海洋特别是赤道以外区域的热带东太平洋和大西洋 ;2 )全球大气年际和年代际变化都主要位于中高纬地区尤其是两极地区 ,在年际时间尺度上 ,气温异常和气压异常没有明显的对应关系 ,但在年代际时间尺度上 ,气温增暖 (变冷 )常常伴随着气压的降低 (升高 ) ;3)在年际时间尺度上 ,发生在中高纬度陆地地区的大气年际变化和主要发生在热带海洋的上层海洋年际变化没有一致性的内在联系 ,前者主要表现为大气的内部 (浑沌 )变化 ,而后者主要为热带海气相互作用产生的 ENSO变化 ;4 )在年代际时间尺度上 ,全球海洋大气系统大约在 70年代前后 ,均一致性地经历了一次跃变 ,其结果是导致 80年代以来 ,全球大范围地区 (尤其是两极和西伯利亚地区 )气温明显偏暖 ,赤道两侧的热带东太平洋、北美和南美西海岸、及非洲西海岸等海域海表面温度偏高 ,伴随着这种全球大范围背景增暖现象 。Temporal and spatial patterns of interannual and interdecadal variations in the global ocean-atmopshere system are documented in this study with two datasets (1950-1998) of the Maryland Ocean Data Assimilation (ODA) analysis and the NCEP/NCAR atmospheric reanalysis.The main conclusions are as follows. 1) Interannual variations in the global upper ocean are characterized by the ENSO mode located in the tropical Pacific,while the interdecadal variations are mainly confined to the high latitudes of the Southern Hemishpere and the off-equator tropical Pacific and Atlantic. 2) Either interannual or interdecadal variations for the atmosphere appear dominantly in the mid-to-high latitudes especially over polar regions,with interannually coherent,but interdecadally incoherent relationships between temperature and sea level pressure anomalies. 3) On the interannual time scale,the atmospheric variability existing in the mid-to-high latitudes seems not to be related to the tropical oceanic variability,since the former is chaos-related while the latter is ENSO-related. 4) On the interdecadal time scale,the global ocean atmosphere system coherently experienced a sudden change around 1970s,which causes a warming trend over the most of the globe in the air temperature especially over the two polar regions and Siberia,as well as in the sea surface temperature over the off-equator tropical eastern Pacific and the western coasts, however,a cooling trend in the air temperature to the north of Tibetan Plateau and around the Greenland,as well as in the sea surface temperature over the high latitudes of the Southern Hemisphere,since 1980s.

关 键 词：海洋-大气系统 年际变化 年代际变化 

分 类 号：P46[天文地球—大气科学及气象学]