楚科奇陆坡流的海表时空特征

Spatiotemporal Variation of Chukchi Slope Current at Surface

【目的】研究2002-2018年楚科奇海表层陆坡流的变化特征。【方法】利用多个卫星高度计融合的海表动力高度和地转流场数据产品,分析2002-2018年8-10月楚科奇海表层陆坡流的时空变化特征。【结果与结论】楚科奇海东北部陆坡流特征明显,研究区域内陆坡流的平均宽度为(41±11)km,平均最大流速为西向(0.15±0.06)m/s,最大流速处离90 m等深线(陆架坡折处)的平均距离为(63±14)km,且流径在向西过程中发生侧向摆动。该3个特征量在8-10月呈季节内变化,宽度主要为25~60 km,最大流速主要为0.06~0.24 m/s,最大流速所在位置距90 m等深线的距离主要为40~80 km,且宽度的最小值、最大流速以及最大流速位置距90 m等深线最小距离均出现在9月。8-10月研究区域陆坡流的3个平均特征量均呈现明显年际变化,2003年平均最大流速较弱且平均宽度最大,2011年和2017年平均最大流速较强且2017年平均宽度较小,这些年份北极海域和南部的阿留申群岛海域的气压及所引起的风场均明显不同。2006年前后陆坡流最大流速和偏东风之间的位相关系变化也体现风场对陆坡流的影响。

【Objective】 To study the spatial and temporal variations of the Chukchi Slope Current at sea surface in 2002-2018. 【Method】 Spatial and temporal variations of the Chukchi Slope Current during August-October from 2002 to 2018 were analyzed using sea surface absolute dynamic topography and geostrophic current datasets which merged different satellite altimeters. 【Result and Conclusion】The feature of the Chukchi Slope Current was significant on the northeastern slope of the Chukchi Sea. At the study area the mean width of the slope current is(41 ± 11) km, the maximum velocity is(0.15 ± 0.06) m/s westward, and the mean distance from the location of the maximum velocity to the 90-m isobaths is(63 ± 14) km with a meandering path of the current. The three features of the current revealed intraseasonal variations from August to October, with the minimum width, the maximum velocity, and the minimum distance from the location of the maximum velocity to the 90-m isobath all showing up in September. For the interannual variations, the current was wide and weak in2003, and was strong in 2011 and 2017 with a narrow feature in 2017, during which the wind fields due to the variations of sea level pressure fields in the northern Arctic region and southern Aleutian region showed different patterns. The variations of the velocity maximum and eastern wind changed from outphase before 2006 to in-phase after 2006, suggesting the influence of wind on the current.