Tracking the evolution processes and behaviors of mesoscale eddies in the South China Sea:a global nearest neighbor filter approach
-
摘要: 本文提出了一种基于全局最邻近滤波的涡旋追踪算法(GNNF),用于探索分析南海中尺度涡旋的时空演化过程以及演化行为特征。该算法主要结合了卡尔曼滤波和最优数据关联技术来实现涡旋的迭代追踪。在追踪模拟生成的涡旋轨迹实验中,GNNF算法的追踪错误率约为0.2%,优于目前常用的其他两种涡旋追踪算法。本文采用GNNF方法对1993-2012年的南海涡旋进行了实例研究,一共提取出4912条生命时间超过一周的涡旋轨迹。通过对其中3445条简单演化轨迹的统计分析,本文发现涡旋的生命演化过程存在比较明显的增长和消亡阶段,涡旋的半径、强度和涡度等属性在生命前半段平缓上升变化,后半段平缓下降,涡旋属性的整个变化趋势基本呈开口向下的抛物线状。通过对演化行为进行分析,本文发现涡旋的产生集中在吕宋岛西北和西南两个区域,而涡旋的消亡集中在西沙群岛附近。涡旋的分裂和合并主要分布在吕宋海峡以西,吕宋岛西北,以及越南外海东南海域,而涡旋消隐重现则主要发生在前面两个区域。通过分析涡旋属性在分裂合并等演化行为的前后变化,本文发现涡旋分裂往往导致半径减小和强度减弱,而能量密度和涡度均增加,相反,合并往往增大涡旋半径和强度,但降低了涡旋的能量密度与涡度。Abstract: The eddy tracking approach is developed using the global nearest neighbor filter (GNNF) to investigate the evolution processes and behaviors of mesoscale eddies in the South China Sea (SCS). Combining the Kalman filter and optimal data association technologies, the GNNF algorithm is able to reduce pairing errors to 0.2% in tracking synthetic eddy tracks, outperforming other existing methods. A total of 4 913 eddy tracks that last more than a week are obtained by the GNNF during 1993-2012. The analysis of a growth and a decay based on 3 445 simple eddy tracks show that eddy radius, amplitude, and vorticity smoothly increase during the first half of lifetime and decline during the second half following a parabola opening downwards. The genesis of eddies mainly clusters northwest and southwest of Luzon Island whereas the dissipations concentrate the Xisha Islands where the underwater bay traps and terminates eddies. West of the Luzon Strait, northwest of Luzon Island, and southeast of Vietnam are regions where eddy splits and mergers are frequently observed. Short disappearances mainly distribute in the first two regions. Moreover, eddy splits generally result in a decrease of the radius and the amplitude whereas eddy mergers induce growing up. Eddy intensity and vorticity, on the contrary, are strengthened in the eddy splits and diminished in mergers.
-
Key words:
- mesoscale ocean eddies /
- eddy tracking /
- eddy split /
- eddy merger /
- South China Sea
-
Ari Sadarjoen I, Post F H. 2000. Detection, quantification, and tracking of vortices using streamline geometry. Computers & Graphics, 24(3):333-341,, doi: 10.1016/S0097-8493(00)00029-7 Bar-Shalom Y, Daum F, Huang J. 2009. The probabilistic data association filter. IEEE Control Systems Magazine, 29(6):82-100,, doi: 10.1109/MCS.2009.934469 Bar-Shalom Y, Fortmann T E. 1988. Tracking and Data Association, Bar-Shalom Y, Li X R, Kirubarajan T. 2001. Estimation with Applications to Tracking and Navigation:Theory, Algorithms and Software. New York:John Wiley & Sons, Inc, doi: 10.1002/0471221279 Blackman S S. 1986. Multiple-target Tracking with Radar Applications. Dedham, MA:Artech House, Inc Cai Shuqun, Long Xiaoming, Wu Renhao, et al. 2008. Geographical and monthly variability of the first baroclinic Rossby radius of deformation in the South China Sea. Journal of Marine Systems, 116(C6):C06018, doi: 10.1029/2010jc006716 Chaigneau A, Gizolme A, Grados C. 2008. Mesoscale eddies off Peru in altimeter records:identification algorithms and eddy spatio-temporal patterns. Progress in Oceanography, 79(2–4):106-119,, doi: 10.1016/j.pocean.2008.10.013 Chelton D B, Schlax M G, Samelson R M. 2011. Global observations of nonlinear mesoscale eddies. Progress in Oceanography, 91(2):167-216,, doi: 10.1016/j.pocean.2011.01.002 Chen Gengxin, Hou Yijun, Chu Xiaoqing. 2011. Mesoscale eddies in the South China Sea:mean properties, spatiotemporal variability, and impact on thermohaline structure. Journal of Geophysical Research, 116(6):C06018, doi: 10.1029/2010JC006716 Chen Gengxin, Hou Yijun, Zhang Qilong, et al. 2010. The eddy pair off western Vietnam:interannual variability and impact on thermohaline structure. Continental Shelf Research, 30(7):715-723,, doi: 10.1016/j.csr.2009.11.013 Chow C H, Hu J H, Centurioni L R, et al. 2008. Mesoscale Dongsha cyclonic eddy in the northern South China sea by drifter and satellite observations. Journal of Geophysical Research, 113(C4):C04018, doi: 10.1029/2007JC004542 Chu Xiaoqing, Xue Huijie, Qi Yiquan, et al. 2014. An exceptional anticyclonic eddy in the South China Sea in 2010. Journal of Geophysical Research, 119(2):881-897,, doi: 10.1002/2013JC009314 Dong Changming, Liu Yu, Lumpkin R, et al. 2011. A scheme to identify loops from trajectories of oceanic surface drifters:an application in the Kuroshio extension region. Journal of Atmospheric and Oceanic Technology, 28(9):1167-1176,, doi: 10.1175/JTECH-D-10-05028.1 Forsyth D A, Ponce J. 2002. Computer Vision:A Modern Approach. Englewood Cliffs, NJ:Prentice Hall He Yinghui, Cai Shuqun, Wang Dongxiao, et al. 2015. A model study of Luzon cold eddies in the northern South China Sea. Deep Sea Research:Part I. Oceanographic Research Papers, 97:107-123, doi: http://dx.doi.org/10.1016/j.dsr.2014.12.007 He Yinghui, Xie Jieshuo, Cai Shuqun. 2016. Interannual variability of winter eddy patterns in the western South China Sea. Geophysical Research Letters, 43(10):5185-5193,, doi: 10.1002/2016GL068842 Henson S A, Thomas A C. 2008. A census of oceanic anticyclonic eddies in the Gulf of Alaska. Deep Sea Research:Part I. Oceanographic Research Papers, 55(2):163-176,, doi:10.1016/j.dsr. 2007.11.005 Isern-Fontanet J, García-Ladona E, Font J. 2006. Vortices of the Mediterranean Sea:an altimetric perspective. Journal of Physical Oceanography, 36(1):87-103,, doi: 10.1175/JPO2826.1 Kuhn H W. 2010. The Hungarian method for the assignment problem. In:Jünger M, Liebling T M, Naddef D, et al., eds. 50 Years of Integer Programming 1958–2008:From the Early Years to the State-of-the-Art. Berlin Heidelberg:Springer, 29-47, doi: 10.1007/978-3-540-68279-0_2 Liu Yu, Dong Changming, Guan Yuping, et al. 2012. Eddy analysis in the subtropical zonal band of the North Pacific Ocean. Deep Sea Research:Part I. Oceanographic Research Papers, 68:54-67,, doi: 10.1016/j.dsr.2012.06.001 Liu Qinyu, Kaneko A, Su Jilan. 2008. Recent progress in studies of the South China Sea circulation. Journal of Oceanography, 64(5):753-762,, doi: 10.1007/s10872-008-0063-8 Morrow R, Birol F, Griffin D, et al. 2004. Divergent pathways of cylonic and anti-cyclonic ocean eddies. Geophysical Research Letters, 31(24):L24311, doi: 10.1029/2004GL020974 Munkres J. 1957. Algorithms for the assignment and transportation problems. Journal of the Society for Industrial and Applied Mathematics, 5(1):32-38,, doi: 10.1137/0105003 Nan Feng, He Zhigang, Zhou Hui, et al. 2011. Three long-lived anticyclonic eddies in the northern South China Sea. Journal of Geophysical Research, 116(C5):C05002, doi:10.1029/2010 JC006790 Nencioli F, Dong Changming, Dickey T, et al. 2010. A vector geometry-based eddy detection algorithm and its application to a high-resolution numerical model product and high-frequency radar surface velocities in the Southern California Bight. Journal of Atmospheric and Oceanic Technology, 27(3):564-579,, doi: 10.1175/2009JTECHO725.1 Okubo A. 1970. Horizontal dispersion of floatable particles in the vicinity of velocity singularities such as convergences. Deep Sea Research and Oceanographic Abstracts, 17(3):445-454,, doi: 10.1016/0011-7471(70)90059-8 Penven P, Echevin V, Pasapera J, et al. 2005. Average circulation, seasonal cycle, and mesoscale dynamics of the Peru Current System:a modeling approach. Journal of Geophysical Research, 110(C10):C10021, doi: 10.1029/2005JC002945 Silverman B W. 1986. Density Estimation for Statistics and Data Analysis. New York:Chapman & Hall Simmons H L, Nof D. 2000. Islands as eddy splitters. Journal of Marine Research, 58(6):919-956,, doi: 10.1357/002224000763485755 Su Jilan. 2004. Overview of the South China Sea circulation and its influence on the coastal physical oceanography outside the Pearl River Estuary. Continental Shelf Research, 24(16):1745-1760,, doi: 10.1016/j.csr.2004.06.005 Thrun S. 2000. Probabilistic algorithms in robotics. Ai Magazine, 21(4):93-109,, doi: 10.1609/aimag.v21i4.1534 Thrun S, Burgard W, Fox D. 2005. Probabilistic Robotics, Wang Guihua, Chen Dake, Su Jilan. 2008. Winter eddy genesis in the western South China Sea due to orographic wind jets. Journal of Physical Oceanography, 38(3):726-732,, doi:10.1175/2007 JPO3868.1 Wang Guihua, Su Jilan, Chu P C. 2003. Mesoscale eddies in the South China Sea observed with altimeter data. Geophysical Research Letters, 30(21):2121, doi: 10.1029/2003GL018532 Weiss J. 1991. The dynamics of enstrophy transfer in two-dimensional hydrodynamics. Physica D:Nonlinear Phenomena, 48(2–3):273-294,, doi: 10.1016/0167-2789(91)90088-Q Welch G, Bishop G. 2001. An Introduction to the Kalman filter. Los Angeles, CA, USA:ACM Press Williams S, Petersen M, Bremer P T, et al. 2011. Adaptive extraction and quantification of geophysical vortices. IEEE Transactions on Visualization and Computer Graphics, 17(12):2088-2095,, doi: 10.1109/TVCG.2011.162 Xiu Peng, Chai Fei, Shi Lei, et al. 2010. A census of eddy activities in the South China Sea during 1993–2007. Journal of Geophysical Research, 115(C3):C03012, doi: 10.1029/2009JC005657 Yi J, Du Y, He Z, et al. 2014. Enhancing the accuracy of automatic eddy detection and the capability of recognizing the multi-core structures from maps of sea level anomaly. Ocean Science, 10(1):39-48 Yi Jiawei, Du Yunyan, Zhou Chenghu, et al. 2015. Automatic identification of oceanic multieddy structures from satellite altimeter datasets. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 8(4):1555-1563 Yuan Dongliang, Han Weiqing, Hu Dunxin. 2007. Anti-cyclonic eddies northwest of Luzon in summer-fall observed by satellite altimeters. Geophysical Research Letters, 34(13):L13610, doi: 10.1029/2007GL029401
点击查看大图
计量
- 文章访问数: 1611
- HTML全文浏览量: 77
- PDF下载量: 755
- 被引次数: 0