Regional Ocean Current Field Construction based on an Empirical Bayesian Kriging Algorithm using Multiple Underwater Gliders

Zhang, R.; Yang, S.; Wang, Y., and Yin, Y., 2020. Regional ocean current field construction based on an empirical Bayesian kriging algorithm using multiple underwater gliders. In: Zheng, C.W.; Wang, Q.; Zhan, C., and Yang, S.B. (eds.), Air-Sea Interaction and Coastal Environments of the Maritime and Polar Silk Roads. Journal of Coastal Research, Special Issue No. 99, pp. 41-47. Coconut Creek (Florida), ISSN 0749-0208.The ocean current is an important component of the complex marine environment. Ocean current forecasting data mainly come from computational simulation, which merges satellite remote sensing data and in situ data measured from marine vehicles. Having a deep understanding of ocean currents is essential for ocean observation and path guidance of ships or other marine vehicles. In this paper, the regional depth-averaged flow is deduced according to the motion characteristics of underwater glider. Through virtual mooring observations of three underwater gliders in the northern South China Sea, sea trial data from June 25th to July 11th 2019 are obtained. After denoising and filtering, the depth-averaged flow data are used to construct the depth-averaged flow field with the spatial interpolation method. Then, the inverse distance weight (IDW) method, radial basis interpolation (RBI) method and empirical Bayesian kriging (EBK) method are adopted to construct the depth-averaged flow field. Thus, the results from the three constructed methods are compared with the real flow field data, demonstrating that the EBK method shows a better balance in interpolation accuracy and performance than the other methods. More specifically, for the EBK method, the mean error value is 0.00441, and the root-mean-square of error is 0.14977, which are lower than those of the other two methods. Furthermore, the evaluation results thoroughly verify the validity of the EBK method and prove that an underwater glider is a useful tool for observing ocean currents.