Assessment of theoretical approaches to derivation of internal solitary wave parameters from multi-satellite images near the Dongsha Atoll of the South China Sea
Assessment of theoretical approaches to derivation of internal solitary wave parameters from multi-satellite images near the Dongsha Atoll of the South China Sea
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DOI：
10.1007/s13131-022-2015-3
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发表时间：
2022-04
影响因子：
1.4
通讯作者：
Huarong Xie;Qing Xu;Q. Zheng;Xuejun Xiong;Xiaomin Ye;Yongcun Cheng
中科院分区：
文献类型：
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作者：
Huarong Xie;Qing Xu;Q. Zheng;Xuejun Xiong;Xiaomin Ye;Yongcun Cheng
本研究评估了Korteweg-de弗里斯（KdV）和非线性薛定谔（NLS）方程解在从卫星图像推导内孤立波（ISW）动力学参数中的准确性和适用性。以南海北方东沙环礁附近5颗空间分辨率为5 ~ 250 m的卫星遥感器拍摄的可见光波段图像为基线。从基线开始，通过两种方法估计了2017年7月10日至13日发生的ISW振幅，并与同期系泊观测结果进行了比较。以无量纲色散参数与无量纲非线性参数的平方之比为判据，明确区分了两种方法的最佳适用范围。对18例的统计表明，在各50%的情况下，KdV和NLS方法给出了更准确的估计ISW振幅。结果表明，两种理论方法计算的ISW振幅的相对误差与对数底斜率密切相关。这可能是由于ISW振幅的非线性增长，传播沿着变浅的温跃层或地形。利用三幅连续卫星图像反演ISW传播速度的试验结果表明，使用多幅（>2幅）卫星图像可以提高反演相速度的精度。同时，如果附近有系泊数据，则ISW的重复多卫星图像可以帮助确定ISW的类型。
This study assesses the accuracy and the applicability of the Korteweg-de Vries (KdV) and the nonlinear Schrödinger (NLS) equation solutions to derivation of dynamic parameters of internal solitary waves (ISWs) from satellite images. Visible band images taken by five satellite sensors with spatial resolutions from 5 m to 250 m near the Dongsha Atoll of the northern South China Sea (NSCS) are used as a baseline. From the baseline, the amplitudes of ISWs occurring from July 10 to 13, 2017 are estimated by the two approaches and compared with concurrent mooring observations for assessments. Using the ratio of the dimensionless dispersive parameter to the square of dimensionless nonlinear parameter as a criterion, the best appliable ranges of the two approaches are clearly separated. The statistics of total 18 cases indicate that in each 50% of cases, the KdV and the NLS approaches give more accurate estimates of ISW amplitudes. It is found that the relative errors of ISW amplitudes derived from two theoretical approaches are closely associated with the logarithmic bottom slopes. This may be attributed to the nonlinear growth of ISW amplitudes as propagating along a shoaling thermocline or topography. The test results using three consecutive satellite images to retrieve the ISW propagation speeds indicate that the use of multiple satellite images (>2) may improve the accuracy of retrieved phase speeds. Meanwhile, repeated multi-satellite images of ISWs can help to determine the types of ISWs if mooring data are available nearby.