The effect of Oceanic South Atlantic Convergence Zone episodes on regional SST anomalies: the roles of heat fluxes and upper-ocean dynamics
The effect of Oceanic South Atlantic Convergence Zone episodes on regional SST anomalies: the roles of heat fluxes and upper-ocean dynamics
复制标题
南大西洋辐合带事件对区域海温异常的影响：热通量和上层海洋动力学的作用
DOI：
10.1007/s00382-022-06195-3
复制
发表时间：
2022
期刊：
影响因子：
4.6
通讯作者：
Sutil, Ueslei A.
中科院分区：
文献类型：
--
作者：
Pezzi, Luciano P.;Quadro, Mario F.;Lorenzzetti, João A.;Miller, Arthur J.;Rosa, Eliana B.;Lima, Leonardo N.;Sutil, Ueslei A.
南大西洋辐合带是南美洲大陆夏季南部的一个大气系统，有时会延伸到邻近的南大西洋。它的特点是持续的、非常大的、西北-东南方向的云带。它在海洋上的存在导致海面冷却，一些过去的研究表明，这是由于广泛的云层导致进入的太阳热通量减少所致。本文研究了西南大西洋(SWA)Sacz洋幕期间的海-气相互作用过程，以及由此产生的海洋混合层中的调制及其对海洋大气边界层的可能反馈。我们的主要兴趣和新成果是验证大洋SACZ如何作用于动力和热力学机制，并对该区域的海面热平衡作出贡献。在我们的海洋Sacz事件模拟中，我们确认了海洋表面的冷却。模式结果表明，表层大气环流和西南大西洋上空大范围云覆盖带的存在，通过相同量级的动力机制和热力学机制的综合作用，促进了海面的冷却。在巴西东南海岸附近、南巴西湾(SBB)和近海，海洋表面温度(SST)在海洋SACZ位置下的区域下降。这种冷却是由到达海面的太阳短波辐射减少和巴西洋流(BC)地区水平热平流减少所造成的复杂组合的结果。BC向南及邻近近海地区热平流的减弱似乎与海洋Sacz事件引起的地面大气环流有关，Sacz事件旋转了地面风，加强了气旋性海洋中尺度涡旋。本研究中发现的另一个奇特特征是，在S 24°和45°W附近，在850hpa的地面和高空都存在一个位于萨克兹西南的大气气旋性涡旋(CVSS)。CVSS通过诱导辐散的Ekman输送和随后的离岸上升流，导致SST从SACCZ位置向西南方向下降。这表明，与大洋SACZ相关的大气表面环流的动力效应不仅限于云带下的区域，而且还向西南方向扩展，在那里CVSS的存在支持大洋SACZ对流活动，并伴随着改变海洋动力学。因此，这些Sacz事件在海洋动力学中产生的变化可能对许多科学和应用气候研究领域具有重要意义。例如，大洋SACZ事件可能会影响污染物的传播路径以及鱼苗在该区域的扩散。
The South Atlantic Convergence Zone (SACZ) is an atmospheric system occurring in austral summer on the South America continent and sometimes extending over the adjacent South Atlantic. It is characterized by a persistent and very large, northwest-southeast-oriented, cloud band. Its presence over the ocean causes sea surface cooling that some past studies indicated as being produced by a decrease of incoming solar heat flux induced by the extensive cloud cover. Here we investigate ocean–atmosphere interaction processes in the Southwestern Atlantic Ocean (SWA) during SACZ oceanic episodes, as well as the resulting modulations occurring in the oceanic mixed layer and their possible feedbacks on the marine atmospheric boundary layer. Our main interests and novel results are on verifying how the oceanic SACZ acts on dynamic and thermodynamic mechanisms and contributes to the sea surface thermal balance in that region. In our oceanic SACZ episodes simulations we confirm an ocean surface cooling. Model results indicate that surface atmospheric circulation and the presence of an extensive cloud cover band over the SWA promote sea surface cooling via a combined effect of dynamic and thermodynamic mechanisms, which are of the same order of magnitude. The sea surface temperature (SST) decreases in regions underneath oceanic SACZ positions, near Southeast Brazilian coast, in the South Brazil Bight (SBB) and offshore. This cooling is the result of a complex combination of factors caused by the decrease of solar shortwave radiation reaching the sea surface and the reduction of horizontal heat advection in the Brazil Current (BC) region. The weakened southward BC and adjacent offshore region heat advection seems to be associated with the surface atmospheric circulation caused by oceanic SACZ episodes, which rotate the surface wind and strengthen cyclonic oceanic mesoscale eddy. Another singular feature found in this study is the presence of an atmospheric cyclonic vortex Southwest of the SACZ (CVSS), both at the surface and aloft at 850 hPa near 24°S and 45°W. The CVSS induces an SST decrease southwestward from the SACZ position by inducing divergent Ekman transport and consequent offshore upwelling. This shows that the dynamical effects of atmospheric surface circulation associated with the oceanic SACZ are not restricted only to the region underneath the cloud band, but that they extend southwestward where the CVSS presence supports the oceanic SACZ convective activity and concomitantly modifies the ocean dynamics. Therefore, the changes produced in the oceanic dynamics by these SACZ events may be important to many areas of scientific and applied climate research. For example, episodes of oceanic SACZ may influence the pathways of pollutants as well as fish larvae dispersion in the region.
登录
查看更多内容
1976-1993 年期间巴西沙丁鱼 (Sardinella brasiliensis) 在巴西湾东南部产卵
DOI：
--
发表时间：
1998
期刊：
影响因子：
--
作者：
Y. Matsuura
通讯作者：
Y. Matsuura
DOI：
--
发表时间：
2006
期刊：
影响因子：
--
作者：
Mauro Cirano;M. M. Mata;Edmo J. D. Campos;N. F. R. Deiró
通讯作者：
N. F. R. Deiró
南美洲和南大西洋辐合区的次月对流变化
DOI：
--
发表时间：
1999
期刊：
影响因子：
--
作者：
B. Liebmann;G. Kiladis;J. Marengo;T. Ambrizzi;John D. Glick
通讯作者：
John D. Glick
通过格兰杰因果关系研究南大西洋辐合带的海气相互作用
DOI：
--
发表时间：
2015
期刊：
影响因子：
--
作者：
G. Tirabassi;C. Masoller;M. Barreiro
通讯作者：
M. Barreiro
影响因子：
3.1
作者：
KODAMA, YM
通讯作者：
KODAMA, YM