2008年夏季楚科奇海余流分布特征

Distribution Characteristics of Residual Current in the Chukchi Sea in Summer 2008

根据2008-08-05-09-07在楚科奇海布放的一套浅水潜标系统(71°40′1.4″N,167°58′54.6″W)获得的海流剖面资料及温盐资料,采用Lanczos余弦滤波的方法,研究了楚科奇海中央水道余流剖面及温盐时间序列的结构和变化特征,对表层余流与风场的关系及影响温盐结构的因素进行了分析。结果表明,余流的方向和大小在垂直方向上存在明显的差异:表层余流全流呈现西向流态,平均流速为19.6cm/s,方向为257.4°,受表层风场影响显著;中、下层的余流全流平均流速为6.6cm/s,流向为29.6°,呈现东北偏北方向。在整个观测期间,温度时间序列表现出剧烈的震荡,振幅达到3.7℃以上,而盐度序列变化缓慢,波动区间相对较小,为32.0～32.8,并表现出逐渐降低的趋势;温盐序列的变化受底层余流分布的影响较弱。

Based on the current profiles from Acoustic Doppler Current Profiler and the temperature and sa- linity data from a shallow mooring deployed in the central channel of the Chukchi Sea （71°40＇1.4＂ N, 167° 58＇54.6＂ W） during August 5 to September 7 in 2008, the distribution characteristics o{ residual current and the time-series structures and variations of temperature and salinity in the central channel were studied and the relationship between the surface residual current and the wind field was analyzed by means of Lanczos-window cosine filter function. In addition, the factors that can possibly affect the structures of temperature and salinity were also discussed. The overall results show that the residual current is vertical- ly quite different in its direction and magnitude. The surface residual current flows entirely westward, with an average velocity of 19.6 cm/s and a direction of 257.4, and is strongly influenced by the surface wind field. The residual currents in the middle and the lower layers flow entirely toward northeast by north and have an average velocity of 6.6 cm/s and a direction of 29.6 . During the whole observation, the time-series variation of temperature fluctuates significantly, being greater than 3.7 ℃ in amplitude. How- ever, the time-series variation of salinity is slow and small in its fluctuation range （32.0-32.8） and tends to decrease gradually. The time-series variations of temperature and salinity are weakly influenced by the bottom residual current.