钱代丽,管兆勇. 2019. 滤除ENSO信号前后夏季热带印度洋海盆尺度海温异常对西太平洋副热带高压的不同影响[J]. 气象学报, (0):-, doi:10.11676/qxxb2019.030
滤除ENSO信号前后夏季热带印度洋海盆尺度海温异常对西太平洋副热带高压的不同影响
Qian Daili, Guan Zhaoyong. 2018. Impacts of sea surface temperature anomaly in tropical Indian Ocean on variations of summertime western Pacific subtropical high: Dependent and independent of ENSO.
投稿时间:2018-04-16  修订日期:2018-09-02
DOI:10.11676/qxxb2019.030
中文关键词:  西太平洋副热带高压,印度洋海盆尺度模,厄尔尼诺,开尔文波,非绝热加热
英文关键词:West Pacific Subtropical High, Indian Ocean basin-wide mode, El Niñ  o, Kelvin wave, Diabatic heating
基金项目:国家自然科学基金重点资助项目(41330425)
作者单位E-mail
钱代丽 南京信息工程大学 气象灾害教育部重点实验室/气象灾害预报预警与评估协同创新中心/气候与环境变化国际合作联合实验室 66181640@qq.com 
管兆勇 南京信息工程大学 气象灾害教育部重点实验室/气象灾害预报预警与评估协同创新中心/气候与环境变化国际合作联合实验室 guanzy@nuist.edu.cn 
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中文摘要:
      本文使用NCEP/NCAR再分析资料、哈德莱海表温度(sea surface temperature,SST)和中国国家气候中心的西太平洋副热带高压(以下简称西太副高)特征指数,对比分析了在ENSO背景下的夏季印度洋(Indian Ocean,IO)海盆尺度模(Indian Ocean basin mode,IOBM)与独立于ENSO的IOBM(以下称pure Indian Ocean basin mode,IOBM_P)对西太副高的不同影响机理。结果表明,滤除前期ENSO信号后,西北太平洋上为冷SSTA,并在其西北侧强迫出Gill型反气旋。另IO与海洋性大陆(Maritime continent,MC)间存在西高东低的海温异常(sea surface temperature anomaly,SSTA)梯度,印度洋暖SSTA激发出的赤道Kelvin波影响至MC西部地区,强迫出的异常大气环流关于赤道基本对称。加之此时我国南海至西北太平洋地区降水偏弱,潜热释放偏少,从而非绝热冷却,导致西太副高异常偏强、偏南。而在前期El Ni?o的影响下,来年夏季IO与MC地区均有利于出现暖海温异常,Kelvin波的影响偏强偏东,强迫出的异常环流偏在北半球,通过“Ekman 抽吸”和非绝热冷却在对流层低层制造出异常负涡度并进而影响西太副高,使其明显偏强、偏西、偏南。由于IOBM_P在2年和8年周期上对西太副高的影响最明显,而ENSO信号中主要是3-7年的短周期振荡,因此,ENSO背景下的印度洋增暖对WPSH的遥强迫实际包含了来自热带中太平洋的3-7年周期信号的滞后影响和印度洋地区局地变化特别是2年和8年周期变化的作用。这些结果对人们深刻理解西太副高变化规律和做出有效预报提供了线索。
英文摘要:
      Using the NCEP/NCAR reanalysis, Hadley sea surface temperature (SST) data and the indices of the Western Pacific Subtropical High (WPSH) provided by National Climate Center (NCC), we have investigated the different impacts of Indian Ocean (IO) SST anomaly (SSTA) dependent and independent of ENSO on variations of summertime WPSH. It is demonstrated that when the preceding El Ni?o signal is removed from SSTA, it is warmer than normal in IO while cooler in the Maritime Continent (MC) in summer. The anomalous anticyclonic circulation appears in the northwest side of the cold SSTA center. At the same time, the warm IO SSTA triggers the Kelvin wave, mainly affecting the region west of MC. The abnormal atmospheric circulations look roughly symmetrical about the equator in the western Pacific. Meanwhile, the abnormal cooling over the South China Sea and the northwest Pacific caused by less laten heat release leads the WPSH to intensify and expand southwestward. However, in the background of early El Ni?o, the SSTA is warm in both IO and MC, resulting in more eastward propagation of Kelvin waves, leading to stronger circulation anomalies north of the equator. The diabatic cooling and the Ekman pumping generate abnormal negative vorticity in the lower troposphere, being favorable for intensification and the southwest expansion of the WPSH. Moreover, in the background of ENSO, the WPSH is forced to vary by the remote forcing of IO SSTA, which actually includes both the lagging effects of the signals with a short period of 3-7 years from the central-east Pacific and the simultaneous impacts of local SSTA in 2yr and 8yr oscillation from the tropical India Ocean. These results are helpful for our better understanding and predicting the variations of WPSH.
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