| 摘要: |
| 基于1955—1999年间太平洋月平均海温资料, 利用经验正交函数(EOF)分解法, 研究了西太平洋暖池海域(120°E—160°W,18°N—16°S)热含量场的时空变化, 并分析了该海域东、西区热含量变化与南方涛动、副热带高压及ENSO的关系。结果表明, 暖池海域热含量场主要包括年变化型、年际变化型和年代际变化型三个模态, 其主要变化周期依次为1.0、3.6和13.7年。相关和合成分析表明, 暖池东、西区热含量的变化均与南方涛动、副热带高压和
ENSO循环有十分密切的关系。
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| 关键词: 西太平洋,暖池,ENSO循环 |
| DOI：10.11693/hyhz200304005005 |
| 分类号: |
| 基金项目:国家重点基础研究发展规划资助项目,G1998040900号第一部分;中国科学院知识创新工程项目,KZCX2-205 |
附件 |
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| VARIATIONS OF HEAT CONTENT FIELD IN THE WESTERN PACIFIC WARM POOL AREA AND THEIR IMPACT |
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ZHANG Qi-Long, WENG Xue-Chuan, CHENG Ming-Hua
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Institute of Oceanology, The Chinese Academy of Science
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| Abstract: |
| The Western Pacific Warm Pool is a sea area where the air-sea interaction is the most intensive in the Pacific, playing an important role in the global climatic variation and occurrence of some climatic calamity. The effect of the Warm Pool on the atmosphere and climate mainly relieson its thermal state changes, while heat content in the Warm Pool is an important index of its thermal state. In this paper, based on the monthly mean sea temperature data set for the Pacific Ocean from 1955 to 1999, the heat contents in 0—100m in the Western Pacific Warm Pool area (120°E—160°W, 18°N—16°S) were calculated, and the spatial and temporal variations of the heat content field were studied by using empirical orthogonal functions (EOFs). The results show that the heat content field mainly comprised three major modes, i.e., annual (EOF1 mode), interannual (EOF2 mode) and interdecadal (EOF3 mode) variations, accounting for 63.4% of the heat content field variance, whose major periods were 1.0a, 3.6a and 13.7a, respectively. The spatial distributions of the heat contentfield had obvious annual meridional variation (EOF1 mode), interannual zonal variation (EOF2 mode) and interdecadal southeast-northwest variation (EOF3 mode). The interannual variations (EOF2 mode) were associated with ENSO, i.e., the heat content increased in the eastern Warm Pool area and decreased in the west part during El Nino events; on the contrary, the heat content decreased in the east part and increased in the west part during La Nina events.
In order to understand the effect of the interannual variations of the heat content field on the Southern Oscillation (SO), the Subtropical High (SH) and ENSO, the heat contents in 0—100m in both the east region (180°~ 160°W, 6°S ~ 4°N) and the west region (145°~ 165°E, 0°~ 8°N), which were the two most significant variation regions in EOF2 mode, were calculated, to delineate the relationships between the heat content in these two regions and SO, SH and ENSO. The results show close relationships between the heat content in both regions and SO/SH. The interannual change in the heat content of the east region led the change in the Southern Oscillation Index (SOI) anomaly by about 1 month (with a correlation coefficient of -0.56), and led the change in SH area index anomaly by about 6 months (correlation coefficient 0.51). For the heat content of the west region, its interannual change lagged behind the change in SOI anomaly by about 1 month (correlation coefficient 0.63) and led the change in SH area index anomaly by about 5 months (correlation coefficient -0.49). Thus, the interannual change of the Western Pacific Warm Pool is the reflection of the air-sea interaction in the tropical Pacific on both ocean and atmosphere. In addition, the heat content in the two regions is correlated well to the SSTA in the Nino3 region, an ENSO index, with their correlation coefficients being 0.50 and -0.75, respectively (at 99% significance level). The composite analysis shows that during ENSO cycles, there were in phase changes between the heat content anomaly in the east region and the SSTA, and the former led the latter by about 2 months; on the contrary, there were out of phase changes between the heat content anomaly in the west region and the SSTA, and the former lagged behind the latter by about 1 month.
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| Key words: Western Pacific, Warmpool, ENSO cycles |
