A statistical analysis of mesoscale eddies in the Bay of Bengal from 22-year altimetry data
-
摘要: 本文使用一种基于SLA数据的涡旋识别方法,通过22年的AVISO高度计测高数据对孟加拉湾的中尺度涡特征进行了研究。本文主要分析了孟加拉湾涡旋的地理分布、涡旋极性、涡旋生命周期和传播距离、涡旋产生和消失位置、涡旋传播方向和移动轨迹、涡旋运动特征、涡旋属性的演化以及涡旋活动的季节和年际变化等特性。涡旋主要分布在孟加拉湾西部海域,并且大部分涡旋向西移动。涡旋极性分布显示气旋涡更经常出现在湾的西北部和南部,而反气旋涡主要出现在湾的东部。在22年间,共追踪探测到生命周期超过30天的气旋涡565个、反气旋涡389个;对所有生命周期和传播距离而言都是气旋涡数量居多。所有观测到的涡旋的运动属性分析显示气旋涡的涡旋平均振幅大于反气旋涡;对平均半径和平均移动速度而言,气旋涡和反气旋涡相差不大。而且,涡旋属性演化显示生命周期超过90天的涡旋具有明显的双阶段演化特征,包括一个前50天的涡旋成长阶段和一个50天之后的涡旋消亡阶段。针对涡旋活动的季节变化,气旋涡在春季居多而反气旋涡在夏季较多;长生命周期的涡旋季节分布显示在孟加拉湾涡旋活动具有明显的季节分布特征。涡旋数量的年际变化与EKE变化有一个明显的负相关。Abstract: Eddy properties in the Bay of Bengal are studied from 22 a archiving, validation and interpretation of satellite oceanographic (AVISO) data using a sea level anomaly (SLA)-based eddy identification. A geographical distribution and an eddy polarity, an eddy lifetime and propagation distances, eddy origins and terminations, eddy propagation directions and trajectories, eddy kinetic properties, the evolution of eddy properties, seasonal and interannual variabilities of eddy activities are analyzed in this area. Eddies exist principally in the western Bay of Bengal and most of them propagate westward. The polarity distribution of eddies shows cyclones prefer to occur in the northwest and south of the Bay of Bengal, while anticyclones mainly occur in the east of the bay. Five hundred and sixty-five cyclones and 389 anticyclones with the lifetime that exceeds 30 d are detected during the 22 a period, and there is a preference for the cyclones for all lifetime and propagation distances. The kinetic properties of all observed eddies show the average amplitude of the cyclones is larger than that of the anticyclones, whereas that is opposite for average radius, and their average velocities are basically the same. Moreover, the evolution of eddies properties reveals that the eddies with a long lifetime that exceeds 90 d have a significant double-stage feature of the former 50 d growth period and the dying period after 50 d. For the seasonal variability of the eddies, the cyclones occur more often in spring while the anticyclones occur more often in summer. The analysis of long-lived eddy seasonal distributions shows that there is the obvious seasonal variation of the eddy activities in the Bay of Bengal. The interannual variability of an eddy number shows an obvious negative correlation with the EKE variation.
-
Key words:
- mesoscale eddy /
- altimetry data /
- Bay of Bengal /
- eddy characteristics /
- seasonal variability /
- interannual variability
-
Babu M T, Kumar P S, Rao D P. 1991. A subsurface cyclonic eddy in the Bay of Bengal. Journal of Marine Research, 49(3):403-410 Babu M T, Sarma Y V B, Murty V S N, et al. 2003. On the circulation in the Bay of Bengal during northern spring inter-monsoon(March-April 1987). Deep-Sea Research:Part Ⅱ. Topical Studies in Oceanography, 50(5):855-865 Chaigneau A, Gizolme A, Grados C. 2008. Mesoscale eddies off Peru in altimeter records:Identification algorithms and eddy spatiotemporal patterns. Progress in Oceanography, 79(2-4):106-119. Chelton D B, Schlax M G. 2003. The accuracies of smoothed sea surface height fields constructed from tandem satellite altimeter datasets. Journal of Atmospheric and Oceanic Technology, 20(9):1276-1302 Chelton D B, Schlax M G, Samelson R M. 2011. Global observations of nonlinear mesoscale eddies. Progress in Oceanography, 91(2):167-216 Chen Gengxin, Wang Dongxiao, Hou Yijun. 2012. The features and interannual variability mechanism of mesoscale eddies in the Bay of Bengal. Continental Shelf Research, 47:178-185 Cheng Xuhua, Xie Shangping, McCreary J P, et al. 2013. Intraseasonal variability of sea surface height in the Bay of Bengal. Journal of Geophysical Research:Oceans, 118(2):816-830 Doglioli A M, Blanke B, Speich S, et al. 2007. Tracking coherent structures in a regional ocean model with wavelet analysis:application to Cape Basin eddies. Journal of Geophysical Research:Oceans, 112(C5):C05043, doi: 10.1029/2006JC003952 Dussurget R, Birol F, Morrow R, et al. 2011. Fine resolution altimetry data for a regional application in the Bay of Biscay. Marine Geodesy, 34(3-4):447-476 Eigenheer A, Quadfasel D. 2000. Seasonal variability of the Bay of Bengal circulation inferred from TOPEX/Poseidon altimetry. Journal of Geophysical Research:Oceans, 105(C2):3243-3252 Hacker P, Firing E, Hummon J, et al. 1998. Bay of Bengal currents during the northeast monsoon. Geophysical Research Letters, 25(15):2769-2772 Isern-Fontanet J, García-Ladona E, Font J. 2003. Identification of marine eddies from altimetric maps. Journal of Atmospheric and Oceanic Technology, 20(5):772-778 Isern-Fontanet J, García-Ladona E, Font J, et al. 2006. Non-Gaussian velocity probability density functions:an altimetric perspective of the Mediterranean Sea. Journal of Physical Oceanography, 36(11):2153-2164 Le Traon P Y, Dibarboure G. 2004. An illustration of the contribution of the TOPEX/Poseidon-Jason-1 tandem mission to mesoscale variability studies. Marine Geodesy, 27(1-2):3-13 Le Traon P Y, Faugère Y, Hernandez F, et al. 2003. Can we merge Geosat follow-On with TOPEX/Poseidon and ERS-2 for an improved description of the ocean circulation?. Journal of Atmospheric and Oceanic Technology, 20(6):889-895 Le Traon P Y, Nadal F, Ducet N. 1998. An improved mapping method of multisatellite altimeter data. Journal of Atmospheric and Oceanic Technology, 15(2):522-534 Lou Hao, Bracco A, Di Lorenzo E. 2011. The interannual variability of the surface eddy kinetic energy in the Labrador Sea. Progress in Oceanography, 91(3):295-311 McWilliams J C. 1990. The vortices of two-dimensional turbulence. Journal of Fluid Mechanics, 219:361-385 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 Pascual A, Faugère Y, Larnicol G, et al. 2006. Improved description of the ocean mesoscale variability by combining four satellite altimeters. Geophysical Research Letters, 33(2):L02611, doi: 10.1029/2005GL024633 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:Oceans, 110(C10):C10021, doi: 10.1029/2005JC002945 Qiu Yun, Li Li. 2006. Review of study on upper ocean circulation in the Bay of Bengal. Advances in Marine Science (in Chinese), 24(4):593-603 Sadarjoen I A, Post F H. 2000. Detection, quantification, and tracking of vortices using streamline geometry. Computers & Graphics, 24(3):333-341 Sangrà P, Pascual A, Rodríguez-Santana Á, et al. 2009. The Canary Eddy Corridor:a major pathway for long-lived eddies in the subtropical North Atlantic. Deep-Sea Research:Part I. Oceanographic Research Papers, 56(12):2100-2114, doi: 10.1016/j.dsr.2009.08.008 Sarma Y V B, Rao E P R, Saji P K, et al. 1999. Hydrography and circulation of the Bay of Bengal during withdrawal phase of the southwest Monsoon. Oceanologica Acta, 22(5):453-471 Schott F A, McCreary Jr J P. 2001. The monsoon circulation of the Indian Ocean. Progress in Oceanography, 51(1):1-123 Somayajulu Y K, Murty V S N, Sarma Y V B. 2003. Seasonal and interannual variability of surface circulation in the Bay of Bengal from TOPEX/Poseidon altimetry. Deep-Sea Research:Part Ⅱ. Topical Studies in Oceanography, 50(5):867-880 Souza J M A C, de Boyer Montégut C, Le Traon P Y. 2011. Comparison between three implementations of automatic identification algorithms for the quantification and characterization of mesoscale eddies in the South Atlantic Ocean. Ocean Science, 7(3):317-334, doi: 10.5194/os-7-317-2011 Sreenivas P, Gnanaseelan C, Prasad K V S R. 2012. Influence of El Niño and Indian Ocean dipole on sea level variability in the Bay of Bengal. Global and Planetary Change, 80-81:215-225 Vinayachandran P N, Masumoto Y, Mikawa T, et al. 1999. Intrusion of the southwest monsoon current into the Bay of Bengal. Journal of Geophysical Research:Oceans, 104(C5):11077-11085 Yu Lisen, O'Brien J J, Yang Jiayan. 1991. On the remote forcing of the circulation in the Bay of Bengal. Journal of Geophysical Research:Oceans, 96(C11):20449-20454
点击查看大图
计量
- 文章访问数: 1280
- HTML全文浏览量: 74
- PDF下载量: 551
- 被引次数: 0