热带西太平洋潜流模拟:(Ⅱ)潜流结构与输运及其季节变化

Simulation of undercurrents in Western Tropical Pacific: (Ⅱ) Velocity structure, transport and the seasonal variations

通过分析积分30a的准全球HYCOM(HYbrid Coordinate Ocean Model)模式结果,研究了热带西太平洋潜流结构与输运及其季节变化。在年平均状态下,新几内亚沿岸潜流流核位于约175m、2.8°S附近,最大流速超过45cm/s,约110km宽;棉兰老潜流流核位于离岸处,约400～800m深度、127.5°～128.5°E范围,最大速度超过3cm/s。在季节时间尺度上,新几内亚沿岸潜流流核位置比较稳定,海流强度与体积输运表现出夏秋季强、冬春季弱的季节变化特征;棉兰老潜流流核位置、流速强度都具有较大的时空变化特征,棉兰老潜流的体积输运约2.5～11.5Sv,其季节变化规律不够明显,2～7月份,体积输运较弱,8～1月份,体积输运较强。

Velocity structure and volume transport of undercurrents in western tropical Pacific and their seasonal variations are studied by analyzing modeling results of a quasi-global HYCOM integrated 30 model years. In the mean state, the core of New Guinea Coastal Undercurrent （NGCUC） is located near about 175m, 2.8° S, with the maximum velocity over 45cm/s, the width about ll0km, and the core of Mindanao Undercurrent （MUC） is located off shore at 400-800m, 127.5-128.5° E, with the maximum velocity 3cm/s. In the seasonal timescale, the core of the NGCUC is stable and its velocity and volume transport is characterized by obvious seasonal variation. Both the core of the MUC and its velocity magnitude are with quite large time-spatial variation. Volume transport of the MUC is about 2.5 - 11.5Sv （Sv=10^6m^3/ s）, without significant seasonal variation, and it is weaker during February through July, and stronger during August through January.