Possible solar modulation of the ENSO cycle
Possible solar modulation of the ENSO cycle
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DOI：
10.2467/mripapers.55.21
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发表时间：
2005-03
影响因子：
--
通讯作者：
K. Kodera;邦彦 小寺
中科院分区：
文献类型：
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作者：
K. Kodera;邦彦 小寺
以往的研究表明，太阳活动可能会影响厄尔尼诺/南方涛动（ENSO）周期，如在对流层两年振荡（TBO）的振幅调制。这项研究表明，由于太阳活动周期的TBO的差异，事实上，来自印度洋海表温度（SST）与太平洋SST的关联的差异。从夏季到冬季，在低太阳活动（LS）期间，随着太平洋变暖，印度洋出现高SST。然而，这种关系在高太阳活动期间是不存在的。这种SST的差异与赤道上空对流活动的分布有关。在HS期间，对流活动在太平洋部门更加局部化，但在LS期间，对流活动在印度洋上更加纬向和延伸。对流层中的垂直速度也存在差异。暖SST区的上升流在LS期间与平流层有联系，而在HS期间仅限于对流层内，这可能是由于太阳对赤道对流层的影响不是由海洋温度的变化引起的，而是通过赤道平流层的纬向环流的变化引起的。这种环流调节对流活动的垂直范围以及沿沿着的水平分布。
Previous studies suggested that solar activity may influence the El Nino/ Southern Oscillation (ENSO) cycle, such as in the modulation of the amplitude of the Tropospheric Biennial Oscillation (TBO). This study shows that the difference of the TBO due to the solar cycle is, in fact, derived from a difference in the association of the Indian Ocean sea-surface temperatures (SSTs) with the Pacific Ocean SSTs. High SSTs appear in the Indian Ocean following a warming in the Pacific Ocean during low solar activity (LS) from summer to winter. However, such a relationship is absent during high solar activity (HS). This difference in SSTs is related to the distribution of convective activity over the equator. Convective activity is more localized over the Pacific sector during HS, but more zonal and extending over the Indian Ocean during LS. Differences are also found in the vertical velocity in the troposphere. Up-welling over a warm SST region is connected to the stratosphere during LS, but limited within the troposphere during HS.A possible mechanism suggested from this study is that the solar influence in the equatorial troposphere does not arise from a change in the ocean temperature, but originates from the equatorial stratosphere through changes in the meridional circulation. This circulation modulates the vertical extent of convective activity as well as the horizontal distribution along the equator.