Oceanic processes of upper ocean heat content associated with two types of ENSO
Oceanic processes of upper ocean heat content associated with two types of ENSO
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与两类 ENSO 相关的上层海洋热含量的海洋过程
DOI：
10.1007/s10872-017-0452-y
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发表时间：
2018
影响因子：
2.3
通讯作者：
Shoude Guan
中科院分区：
文献类型：
--
作者：
Junqiao Feng;Feifei Jin;Dunxin Hu;Shoude Guan
利用次表层海洋热量收支分析方法，研究了两种类型的厄尔尼诺-南方涛动（ENSO）过程中赤道太平洋上层海洋热含量（HC）和次表层海洋热量的时空变化特征。结果表明，两种ENSO过程中HC的变化趋势主要受混合层下海洋热平流向温跃层的输送控制，地面净热通量的作用可以忽略。其中最重要的三项是气候流引起的纬向和垂直异常热量平流（QUT ′，QW 0 T ′）和气候流引起的纬向异常热量平流（QU′ T 0）。QU 0 T ′的贡献较大，沿着赤道太平洋由西向东延伸。QU ′ T0的贡献主要集中在160°W以东，而QW 0 T ′的贡献主要集中在180°E ~ 120°W之间的中太平洋。特别是在EP ENSO期间，在100°W以东的远东太平洋也观测到QW 0 T ′的主要贡献。异常流对气候学热量的纬向平流（QV′T0）也有很小的贡献。而气候流引起的异常热量纬向平流（QV 0 T ′）和气候流引起的异常热量垂直平流（QW′T0）则是影响HC趋势的两个阻尼因子，其中前者占主导地位。与两种类型的ENSO热平流的空间分布的差异也被提出。我们将暖水热指数（WWH）定义为在130°E-80°W和5°S-5°N范围内的等密度线深度超过26 kg m− 3的积分热含量。进一步的研究表明，WWH的充放电参与了两种类型的厄尔尼诺现象，尽管有一些差异。首先，在EP（CP）ENSO期间，充放电周期的演变需要大约42（55）个月。第二，EP厄尔尼诺事件在放电阶段达到峰值，在补给时间之后的7-8个月。CP厄尔尼诺在补给阶段达到峰值，在补给时间之前4-5个月。厄尔尼诺成熟期HC异常相对于补充期HC异常的位置解释了EP和CP厄尔尼诺峰值出现在补充-释放过程不同阶段的原因。
The spatiotemporal variability of equatorial Pacific upper ocean heat content (HC) and subsurface heat during two types of El Niño-Southern Oscillation (ENSO), namely eastern and central Pacific (EP and CP) types, is investigated using subsurface ocean heat budget analysis. Results show that HC tendencies during both types of ENSO are mainly controlled by oceanic heat advection beneath the mixed layer to the thermocline, and the role of net surface heat flux can be neglected. The most important three terms are the zonal and vertical advections of anomalous heat by climatological currents (QU0T′,QW0T′) and zonal advection of climatological heat by anomalous current (QU′T0). The large contribution ofQU0T′ extends from west to east along the equatorial Pacific. The considerable contribution ofQU′T0is confined to the east of 160°W, and that of theQW0T′ is observed in the central Pacific between 180°E and 120°W. In particular, a major contribution ofQW0T′ is also observed in the far eastern Pacific east of 100°W during EP ENSO. There is also a small contribution from meridional advection of climatological heat by anomalous current (QV′T0). In contrast, the meridional advection of anomalous heat by climatological currents (QV0T′) and vertical advection of climatological heat by anomalous current (QW′T0) are two damping factors in the HC tendency, with the former dominating. Differences in spatial distribution of the heat advection associated with the two types of ENSO are also presented. We define a warm water heat index (WWH) as integrated heat content above 26 kg m−3potential density (26σɵ) isopycnal depth within 130°E–80°W and 5°S–5°N. Further examination suggests that the recharge–discharge of WWH is involved in both types of El Niño, though with some differences. First, it takes about 42 (55) months for the evolution of a recharge–discharge cycle during an EP (CP) ENSO. Second, the EP El Niño event peaks during the discharge phase, 7–8 months after the recharge time. The CP El Niño peaks during the recharge phase, 4–5 months before the recharge time. The locations of HC anomalies in the El Niño mature phase relative to those at recharged time explain why the EP and CP El Niño peak in different stages of the recharge–discharge process.