Seasonal spreading of the Persian Gulf Water mass in the Arabian Sea
Seasonal spreading of the Persian Gulf Water mass in the Arabian Sea
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DOI：
10.1029/2000jc000480
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发表时间：
2001-08
影响因子：
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通讯作者：
T. Prasad;M. Ikeda;S. P. Kumar
中科院分区：
文献类型：
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作者：
T. Prasad;M. Ikeda;S. P. Kumar
基于两个月的温度和盐度气候学，利用与波斯湾水团（PGW）相关的地下最大盐度特征来量化波斯湾水团在阿拉伯海温跃层中的扩散和混合。对波斯湾地区热通量和淡水通量的季节性循环的研究表明，PGW的形成是由于冬季蒸发冷却加剧加上日照减少造成的。给出了在σθ = 26.5处的深度、盐度和地转流分布图，该分布图与PGW岩心基本重合。经过霍尔木兹海峡的强烈混合，性质场表明，温暖（> - 17°C）和高盐度（> - 36.2 psu）的PGW进入阿拉伯海，在200 - 300 m之间形成地下盐度极值。我们发现阿拉伯海PGW分布的变异性与阿拉伯海环流的季风变化有关。冬季季风期间，PGW沿西边界向南扩展；在夏天是不存在的。在冬季，来自孟加拉湾的低盐度水在10°N以南地区和沿印度西海岸的侧向混合说明了这些路径上PGW特征的变化。在夏季，整个温盐结构沿着索马里和阿拉伯海岸垂直移位，与Findlater Jet有关。阿拉伯海中部的Ekman辐合是PGW加深的原因。横向或垂直混合都会引起这些区域PGW性质的变化。在此期间，PGW主要沿着阿拉伯海中部向南扩散，这是高盐度的舌头所表明的。
The characteristics of the subsurface salinity maximum associated with the Persian Gulf Water mass (PGW) are used to quantify the spreading and mixing of PGW in the thermocline of the Arabian Sea based on a bimonthly climatology of temperature and salinity. Examination of the seasonal cycles of heat and freshwater fluxes in the Persian Gulf region indicates that PGW forms as a result of elevated evaporative cooling in conjunction with reduced insolation during winter. Maps are presented of the distributions of depth, salinity, and geostrophic flow on σθ = 26.5, which nearly coincides with the core of the PGW. After intense mixing in the Strait of Hormuz, the property fields suggest that warm (>17°C) and high-salinity (>36.2 psu) PGW enters the Arabian Sea to form a subsurface salinity extremum between 200 and 300 m. We have found variability in the distribution of PGW in the Arabian Sea associated with monsoonal changes in the Arabian Sea circulation. During the winter monsoon, there is southward spreading of PGW along the western boundary; during summer it is not present. Lateral mixing with low-salinity water from the Bay of Bengal in the region south of 10°N and along the west coast of India during winter accounts for changes in the characteristics of PGW along these paths. Associated with the Findlater Jet during summer, the entire thermohaline structure is vertically displaced along the coasts of Somalia and Arabia. Ekman convergence in the central Arabian Sea accounts for deepening of the PGW. Either lateral or vertical mixing would cause changes in PGW properties in these regions. During this time, PGW spreads predominantly southward along the central Arabian Sea, as indicated by a tongue of high salinity.