A decadal spiciness mode in the tropics
A decadal spiciness mode in the tropics
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DOI：
10.1029/1999gl002348
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发表时间：
2000-01
影响因子：
5.2
通讯作者：
N. Schneider
中科院分区：
文献类型：
--
作者：
N. Schneider
对一个复杂气候模式的分析表明，热带太平洋存在一种海洋-大气耦合变率模式，具有以下动力学特征。异常强的太平洋信风加速了北赤道流和逆流。在10° ~ 15°N的中太平洋温跃层，这引起等密度面上温度和盐度平均梯度的异常平流，并产生0.3°K量级的冷/鲜辣度异常。这些都是平流的平均环流通过西边界地区的赤道太平洋在大约五年。在赤道露头的等密度线，冷/新鲜的异常影响表面热量收支，并被假设为启动信风的放松，这是加强了正反馈与温跃层的斜率和海气通量的热量和淡水。在5°到10°S，贸易量的减少是由异常平流冷/新鲜辣度异常产生的，这些异常在一到两年内迁移到赤道，并提供正反馈。在10° ~ 15°N，信差的减少使北赤道流和逆流减速，并导致等密度线上的暖/咸异常，这些异常在5年后到达赤道并关闭循环。
Analysis of a complex climate model suggests the existence of a mode of coupled ocean‐atmosphere variability in the tropical Pacific with the following dynamics. Anomalous strong Pacific trade winds accelerate the North Equatorial current and Countercurrent. At 10° to 15°N in the central Pacific thermocline this causes anomalous advection across mean gradients of temperature and salinity on isopycnal surfaces and generates cool/fresh spiciness anomalies of the order of 0.3°K. These are advected by the mean circulation via the western boundary region to the equatorial Pacific in approximately five years. At the equatorial outcrops of the isopycnals, the cool/fresh anomalies affect the surface heat budget and are hypothesized to initiate a relaxation of the trade winds that is reinforced by positive feedbacks with the slope of the thermocline and with air‐sea fluxes of heat and freshwater. At 5° to 10°S the decrease of the trades generates by anomalous advection cool/fresh spiciness anomalies that migrate to the equator in one to two years and provide a positive feedback. At 10° to 15°N, the decrease of the trades decelerates North Equatorial current and Countercurrent and causes warm/salty anomalies on isopycnals that arrive at the equator five years later and close the cycle.