Observed features of temperature, salinity and current in central Chukchi Sea during the summer of 2012
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摘要: 2012年夏季中国开展了第五次北极科学考察。其间, 在楚科奇海中部(169°00.654'W, 69°30.155'N)布防并回收了一套潜标观测系统, 获得了50天的温度、盐度和海流剖面数据。在本文中我们分析了温度、盐度和流速剖面数据的特征, 获得如下主要结果:(1)总体上, 盐度随深度增加而增大, 温度则随之降低。观测数据的平均温盐分别为2.98℃和32.21 (PSU)。(2)温度和盐度有着很好的负相关性, 相关系数为-0.84。但二者并非总是同步变化的, 在不同的时期呈现不同的共变特征。(3)整个水柱的平均流速为141mm/s, 平均流速方向为347.1°。流速统计分布曲线的宽度随深度的增加而逐渐变窄。北向的海流占观测总体的85%以上, 平均流速介于100-150mm/s之间。(4)从旋转谱分析结果得知, 该点的流速变化以低频变化为主, 最显著谱峰位于0.012 cph处 (对应约3.5天的变化周期), 潮汐运动不显著。(5)各层流速特征的时间变化基本相同, 但随着深度的增加, 流速稍有减弱, 方向向左偏转。海流方向与海表面风向有较好的一致性。在南风条件下单位面积上平均北向水体输运为0.1-0.2m3/s, 但北风爆发时则约为-0.2m3/s。Abstract: During the summer of 2012, the fifth CHINARE Arctic Expedition was carried out, and a submersible mooring system was deployed in M5 station located at (69°30.155'N,169°00.654'W) and recovered 50d later. A set of temperature, salinity and current profile records was acquired. The characteristics of these observations are analyzed in this paper. Some main results are achieved as below. (1) Temperature generally decreases while salinity generally increases with increasing depth. The average values of all records are 2.98℃ and 32.21 psu. (2) Salinity and temperature are well negatively correlated, and the correlation coefficient between them is -0.84. However, they did not always vary synchronously. Their co-variation featured different characters during different significant periods. (3) The average velocity for the whole water column is 141 mm/s with directional angle of 347.1°. The statistical distribution curve of velocity record number gets narrower with increasing depth. More than 85% of the recorded velocities are northward, and the mean magnitudes of dominated northward velocities are 100-150 mm/s. (4) Rotary spectrum analysis shows that motions with low frequency take a majority of energy in all layers. The most significant energy peaks for all layers are around 0.012 cph (about 3.5 d period), while the tidal motion in mooring area is nonsignificant. (5) Velocities in all layers feature similar and synchronous temporal variations, except for the slight decrease in magnitude and leftward twist from top to bottom. The directions of velocity correspond well to those of surface wind. The average northward volume transport per square meter is 0.1-0.2 m3/s under southerly wind, but about -0.2 m3/s during northerly wind burst.
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