| 摘要: |
| 高频地波雷达可以提供沿岸大面积海表流的观测,但单个地波雷达只能提供径向流观测。本研究发展了一套二维变分(Two-Dimensional VARiational Method， 2DVAR)数据融合方法，将台湾海峡海域的地波雷达径向流数据与ROMS (Regional Ocean Model System)模式输出结果进行融合，得到一套较好的融合产品。结果显示，融合产品与雷达径向流的平均相对误差相较于模式输出与雷达径向流的平均相对误差由9.70%降低至1.54%。为进一步检验融合方法，设计了两种独立样本试验。试验一将雷达径向流按空间均匀划分为融合样本与独立样本，使用雷达融合样本与模式输出进行融合，此时融合结果的平均均方根误差(Root Mean Square Error, RMSE)相较于模式输出由0.41 m/s降低至0.19 m/s。试验二将雷达径向流和模式输出在空间上都均匀划分为融合样本与独立样本，对两种数据的融合样本进行融合，使用TC (Triple Collocation)方法估计模式输出、雷达观测与融合结果的误差方差，此时融合结果的平均误差方差最小，且其误差方差相对于独立的雷达径向流与模式输出在远岸处有明显减小。以上结果都表明融合数据更加接近实际海流，证明了2DVAR方法融合海表流的有效性。 |
| 关键词: 海洋水文学 海表流场 2DVAR 高频地波雷达 台湾海 |
| DOI：10.3969/J.ISSN.2095-4972.2020.04.003 |
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| 基金项目:国家重点研发计划资助项目(2016YFC1401600)；国家海洋局公益资助项目(201505003 05) |
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| Application of 2DVAR method in sea surface current blending in Taiwan Strait |
| ZOU Ting,ZHU Da-yong,ZHANG Jun-peng,WANG Xiao-chun |
| (College of Marine Science， Nanjing University of Information Science and Technology， Nanjing 210044， China;Third Institute of Oceanography， MNR， Xiamen 361005， China) |
| Abstract: |
| As an emerging sea state monitoring device, HF radar can provide observations of large-scale sea surface currents along the coastal region. However, a single HF radar can only provide radial flow observation. This paper develops a two-dimensional variational method (2DVAR), which blends radial current observation with surface ocean current vector from the ROMS (regional ocean model system) model of Taiwan Strait to obtain a blended pro duct. The results show that the average relative error of the blended product and the radar radial flow is reduced from 9.70% to 1.54% compared to the average relative error of the model output and the radar radial flow. To further examine the blending method, two independent sampling experiments were designed using the original data. In the first experiment, the radar radial flows were evenly divided into blending samples and independent samples in space. The blending samples of radial velocity observation were then blended with the model output. The mean root mean square error (RMSE) of the blended result is 0.19 m/s compared with the RMSE of model output of 0.41 m/s. In the second experiment, both the radar radial flow and the model output were spatially evenly divided into blending samples and independent samples, and the blending samples of the two kinds of data were blended. The average error variance of the blended result, estimated using the TC (triple collocation) method, is the smallest. And the error variance of the blended result is significantly reduced at the far shore region compared with the error variance of the independent radar radial flow as well as the error variance of the model output. All the above results show that the blended product is closer to the true current, which proves the effectiveness of the 2DVAR method for blending sea surface currents. |
| Key words: marine hydrology sea surface current 2DVAR HF radar Taiwan Strait |
