Ocean Turbulence Estimation Using Fast-response Thermistor with A Free-fall Vertical Microstructure Profiler

基於自由落體式垂向剖面儀觀測的溫度脈動信號對海洋湍流混合進行估計

10.6937/TWC.201912_67(4).0005

陳雪(XUE CHEN)；欒新(XIN LUAN)；宋大雷(DA-LEI SONG)

Turbulence ； Free-fall ； Shear ； Temperature microstructure ； Dissipation rate ； 湍流 ； 自由落體 ； 剪切 ； 溫度脈動 ； 耗散率

台灣水利

67卷4期（2019 / 12 / 01）

48 - 56

英文

The newly designed ocean turbulence free-fall vertical microstructure profiler (FVMP) developed by Ocean University of China (OUC) had been successfully deployed in the Western Pacific with the descend speed of 0.35-0.4 m/s. During the observation period, the signals collected by the FVMP included both temperature microstructure and two perpendicular components of horizontal velocity shear microstructure of every vertical profile. By analyzing the attitude of the FVMP, the results suggest that the platform satisfies the requirements of stability. Estimation of ocean turbulence with a fast-response thermistor is examined by comparing the energy dissipation rate ε_T from a FP07 thermistor with ε from a shear probe, both of which are attached to the free-fall microstructure profiler. The power spectrum curves of the observed temperature microstructure signals match well with the theoretical spectrum and the calculated turbulence dissipation rates are 10^(-8)-10^(-9) W kg^(-1) approximately. Hence it could be available to estimate ocean turbulence using fast-response thermistors with the FVMP, which extends the possibility to obtain much more turbulence data in deep and wide oceans.

由中國海洋大學（Ocean University of China, OUC）自主研發的自由落體式垂向微尺度剖面儀（Free-fall Vertical Microstructure Profiler, FVMP）在西太平洋成功布放，垂向剖面儀在布放過程中以0.35～0.4 m/s的速度做近似勻速下潛運動。在海洋湍流觀測過程中，該垂向剖面儀上安裝的FP07快速響應熱敏電阻用於測量溫度脈動信號，兩個正交的剪切探頭用於采集水平速度剪切在兩個垂直正交方向上的分量信號。通過對垂向剖面儀上搭載的姿態傳感器觀測的姿態信號進行分析，結果表明，自治的垂向剖面儀具有良好的穩定性，能夠滿足深海湍流混合的測量要求。對於觀測的多參數海洋湍流信號，基於溫度脈動信號對湍動能耗散率ε_T進行了間接計算，並將計算結果值與基於速度脈動信號直接計算的湍動能耗散率ε進行了壹致性的對比分析。經分析得到，觀測的溫度脈動波數譜與標準理論譜吻合較好，基於溫度脈動信號計算得到的湍動能耗散率約為10^(-8)-10^(-9) W kg^(-1)。因此，可以認為在垂向剖面儀上搭載快速響應熱敏電阻進行海洋湍流混合的估計是壹種有效的方式，該測量方式采集的湍流數據是可靠有效的，是可用於研究深海湍流混合的可靠平臺。

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