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陈宏莉, 徐海明, 马静, 等. 2022. 月内尺度上与冬季北太平洋大范围海温暖异常相联系的海气相互作用特征[J]. 大气科学, 46(2): 293−308. doi: 10.3878/j.issn.1006-9895.2106.21047
引用本文: 陈宏莉, 徐海明, 马静, 等. 2022. 月内尺度上与冬季北太平洋大范围海温暖异常相联系的海气相互作用特征[J]. 大气科学, 46(2): 293−308. doi: 10.3878/j.issn.1006-9895.2106.21047
CHEN Hongli, XU Haiming, MA Jing, et al. 2022. Characteristics of Air–Sea Interaction Associated with Large-Scale Sea Surface Temperature Warm Anomalies over the North Pacific in Winter on Submonthly Timescales [J]. Chinese Journal of Atmospheric Sciences (in Chinese), 46(2): 293−308. doi: 10.3878/j.issn.1006-9895.2106.21047
Citation: CHEN Hongli, XU Haiming, MA Jing, et al. 2022. Characteristics of Air–Sea Interaction Associated with Large-Scale Sea Surface Temperature Warm Anomalies over the North Pacific in Winter on Submonthly Timescales [J]. Chinese Journal of Atmospheric Sciences (in Chinese), 46(2): 293−308. doi: 10.3878/j.issn.1006-9895.2106.21047

月内尺度上与冬季北太平洋大范围海温暖异常相联系的海气相互作用特征

Characteristics of Air–Sea Interaction Associated with Large-Scale Sea Surface Temperature Warm Anomalies over the North Pacific in Winter on Submonthly Timescales

  • 摘要: 本文采用1985~2015年美国气象环境预报中心及能源部(NCEP/DOE)再分析以及美国国家海洋大气管理局(NOAA)海温(SST)等资料,基于大范围SST异常的确定规则,在北太平洋区域选取了8个暖事件,采用跟随SST异常中心的动态合成方法,研究分析了冬季北太平洋生命史为50天左右的大范围SST暖异常在其盛期前后的月内尺度海气结构特征。结果表明:(1)大范围SST暖异常前期主要表现为大气对海洋的强迫作用,后期则主要表现为海洋对大气的强迫作用。(2)SST暖异常伴随的大气结构在前后期发生了明显的转变,前期SST暖异常上空伴随着相当正压的偶极型气压异常(即东北侧为异常高压而西南侧为异常低压),对应大气偏东风异常。后期SST暖异常区北侧上空伴随着相当正压的低压异常,南侧为弱高压异常,对应大气偏西风异常。(3)在SST暖异常后期大气出现了气旋式环流异常响应,这主要是因为高频瞬变涡旋反馈强迫在起关键作用,且瞬变涡度的强迫作用是主要贡献因子。(4)海流结构在前后期也发生了明显的转变,前期海洋动力过程不利于维持SST暖异常,后期异常暖平流和异常下沉流均有助于维持SST暖异常及其对大气的影响。

     

    Abstract: Using the National Centers for Environmental Prediction/Department of Energy reanalysis 2 and the National Oceanic and Atmospheric Administration sea surface temperatures (SSTs) during the 1985–2015 period, eight warm events in the North Pacific are selected based on the definition of large-scale SST anomalies. The dynamic composite method, following the SST anomaly center, is used to study the large-scale SST warm anomalies with a lifespan of 50 days over the wintertime North Pacific and associated characteristics of the air–sea interaction on submonthly timescales before and after their peak stages. The results show the following: (1) The early stage of the large-scale SST warm anomalies are mainly characterized by the forcing of the atmosphere on the ocean, whereas the late stage is dominated by the forcing of the ocean on the atmosphere. (2) The atmospheric structure associated with the SST warm anomalies changes significantly from the early to late stages. The early stage shows an equivalent barotropic dipole pattern of pressure anomalies above the warmer SSTs, with an anomalous high in the northeast and an anomalous low in the southwest, corresponding to the anomalous easterly wind over SST anomalies. At the late stage, an equivalent barotropic anomalous cyclone is located to the north of warmer SSTs, with a weak anomalous anticyclone to the south, corresponding to the anomalous westerly wind over SST anomalies. (3) The cyclonic circulation anomaly occurs at the late stage mainly due to the high-frequency transient eddy vorticity feedback forcing, which acts as the major contributing factor. (4) The structure of the ocean current is also different between the early and late stages. At the early stage, the ocean dynamic process is not conducive to maintaining the SST warm anomalies. At the late stage, both anomalous warm advection and anomalous downwelling act to maintain the SST warming and thus its influence on the atmosphere.

     

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