RECORD COASTAL UPWELLING IN THE CALIFORNIA CURRENT IN 1999
RECORD COASTAL UPWELLING IN THE CALIFORNIA CURRENT IN 1999
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1999 年加利福尼亚州沿岸上升流创纪录
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
K. Sakuma
中科院分区：
文献类型：
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作者：
Franklin U. Sczhwing;S. Ralston;K. Sakuma
根据直接和间接观测，描述了 1999 年春季和夏季加州海流系统 (CCS) 大部分地区出现的极其不寻常的沿海上升流水平。 1999 年的风和海洋异常（以赤道 La Niiia 为特征的时期）与前几年的气候趋势进行了比较，并与 1997-98 年 El Niiio 事件相关的极端情况进行了特别对比。 1999 年春季和夏季 CCS 的状况与极高水平的持续沿海上升流一致。太平洋渔业环境实验室 (PFEL) 上升流指数自 1946 年以来连续创历史新高。从 1998 年末到 1999 年的大部分时间，在沿海浮标处测得强劲、持续的上升流有利风。沿海海面温度 (SST) 比 1999 年春季的季节平均值低 3"-4"C，比该地区的出口温度低约 10"。 1997 年底发生的一次。加利福尼亚州中部附近的水文调查表明，相对于长期春季平均水位上升 100 米或更多，CCS 北部的沿海海平面 (CSL) 异常为至少 65 年来的最低水平，这意味着加利福尼亚洋流向南的输送量比平时要大，这可能与不寻常的海洋状况和从厄尔尼奥岛到拉尼亚岛的显着转变有关。 CCS 的物理条件可能会迅速而剧烈地变化，其海洋种群的反应似乎也几乎同样迅速。 1999 年发生的巨大物理和生物变化可能标志着 CCS 新气候制度的启动。 简介 在不到两年的时间里，加州洋流系统 (CCS) 大部分地区的海面温度 (SST) 从 1997 年末厄尔尼奥高峰期间的有记录以来的最高温度下降。比季节平均值高 6°C；Lynn 等人，1998 年）到 1999 年几十年来未见的低温（比正常值低 3 英寸以上）。这种快速冷却是前所未有的，特别是在
An extremely unusual level of coastal upwelling in the spring and summer of 1999 over much of the California Current system (CCS) is described, based on direct and indrect observations. Wind and ocean anomalies in 1999, a period characterized by an equatorial La Niiia, are compared to climate trends for the previous several years, and specifically contrasted with the extremes associated with the 1997-98 El Niiio event. Conditions in the CCS during the spring and summer of 1999 were consistent with extremely high levels of sustained coastal upwelling. The Pacific Fisheries Environmental Laboratory (PFEL) upwelling indices reached record highs for a series ex- tending back to 1946. Strong, sustained upwelling- favorable winds were measured at coastal buoys through late 1998 and much of 1999. Coastal sea-surface teni- peratures (SSTs) were 3"-4"C below their seasonal mean in spring 1999, and about 10" cooler than the region ex- perienced in late 1997. Hydrographic surveys off central California suggest upwelling of water by 100 m or more relative to the long-term spring average. Coastal sea-level (CSL) anomalies in the northern CCS were the lowest in at least 65 years. Greater than usual southward trans- port by the California Current is implied. A number of population and ecological changes observed during this period may be linked to the unusual ocean conditions and the striking transition from El Niiio to La Niiia. Physical conditions in the CCS can change swiftly and dramatically, and its marine populations appear to re- spond nearly as rapidly. The large physical and biological changes that occurred in 1999 may signi@ the initiation of a new climate regime for the CCS. INTRODUCTION In less than two years sea-surface temperatures (SSTs) over much of the California Current system (CCS) dropped from the warmest on record during the height of El Niiio in late 1997 (as much as 6°C above the sea- sonal mean; Lynn et al. 1998) to low temperatures in 1999 not seen in decades (more than 3" below normal). This rapid cooling is unprecedented, particularly in the