热带西北太平洋0~300 m热含量的年代际变化

太平洋是海表温度年际变化和年代际变化发生的主要区域，但对太平洋海洋热含量变化的研究相对较少。为此, 本文分析了1980—2020年太平洋上层(0~300 m)热含量的时空变化特征。基于IAP数据，本文首先利用集合经验模态分解法(EEMD)提取不同时间尺度的海洋热含量信号，并利用正交经验分解法(EOF)对不同时间尺度的海洋热含量进行时空特征分析，得到了太平洋0~300 m海洋热含量的年际变化、年代际变化以及长期变暖的时空特征。结果表明，除了年际变化之外，热带西北太平洋上层热含量还存在明显的年代际变化和长期变暖趋势。在东太平洋和高纬度西太平洋，热含量的年代际变化特征并不突出。热带西北太平洋热含量的年代际变化在1980—1988年和1999—2013年较高，而在1989—1998年和2014—2020年期间较低。此外，针对热带西北太平洋热含量的经向、纬向和垂向特征分析，发现这种年代际变化主要发生在5°N—20°N，120°E—180°E，次表层50~200 m范围内。热带西北太平洋热含量的年代际变化对全球海表温度的年代际变化有着重要作用。

Interdecadal variation of ocean heat content at depth of 0-300 m in the tropical northwest Pacific

The Pacific Ocean is the main region occurring the interannual and interdecadal variabilities of sea surface temperature. Comparing to the sea surface temperature, the variabilities of ocean heat content in the Pacific Ocean were less studied. Therefore, this paper studied the variabilities of ocean heat content (at depth of 0 300 m) in the Pacific Ocean during the period from 1980 to 2020. The Ensemble Empirical Mode Decomposition method (EEMD) was applied to the Institute of Atmospheric Physics (IAP) heat content data to extract the signals at different time scales, and then the Empirical Orthogonal Function (EOF) was applied to analyze the temporal and spatial characteristics of the ocean heat content at different time scales. The results showed that besides the interannual variation, there were also evident interdecadal variations and long term warming trends of heat content at depth of 0~300 m in the tropical northwest Pacific. In the eastern Pacific and the high latitude western Pacific, the interdecadal variability of heat content was not prominent. In the tropical northwest Pacific, the heat content was higher during 1980 1988 and 1999 2013 than those during 1989 1998 and 2014 2020. Our analysis showed that the interdecadal variability was mostly occurred at 5°N—20°N, 120°E—180°E, and at depth of 50 200 m in the tropical northwestern Pacific. The interdecadal variation of ocean heat content in the tropical northwestern Pacific played an important role in the interdecadal variation of global sea surface temperature.