基于GIS的南海中尺度涡旋典型过程的特征分析

GIS-based analysis on temporal-spatial features of typical processes of meso-scale eddies in the South China Sea

以具有复杂时空演变过程的海洋中尺度涡旋为研究对象，以定量表达和组织涡旋典型过程案例为前提，基于Global NLOM（NavalResearchLaboratoryLayeredOceanModel）所得的SSH（SeaSurfaceHeight）、SST（SeaSurfaceTemperature）和表层海流场，对海洋中尺度涡旋进行综合辨认和动态跟踪。以南海为例，通过提取涡旋典型过程中的典型状态，建立中尺度涡旋典型案例库。然后以库中所有过程案例为对象对涡旋进行GIS（GeographicInformationSystem）时空特征分析。所得结果为：（1）南海中尺度涡旋整体上呈东北．西南向分布，涡旋水平移动速度为3～16cm／s，平均速度为8．4cm／s。（2）大部分涡旋向西移动。春夏季涡旋主要向西北方向移动，秋冬季涡旋主要向西南方向移动。（3）南海东北部涡旋主要集中在9～10月以及次年的1～2月发生，涡旋先向西北方向移动，后又转向西南方向移动，大部分中尺度涡旋不能西移太远。南海中部气旋涡主要发生在冬、春两季。一部分涡旋沿陆坡向西南运动，其中一些反气旋涡沿南海海盆向西运动。南海东南部在研究期内只有反气旋涡出现，向西或西北偏西运动，这里的涡旋比较弱，但移动距离较长，也有较长的生命周期。南海西南部夏季出现的涡旋多于冬季，且夏季的绝大部分涡旋以偶极子结构出现，该区域涡旋移动的距离较小。该研究引入GIS技术，基于大量时空数据对具有复杂时空特征的中尺度涡旋的信息进行组织、存储，以期通过对涡旋生消过程的时空分析来揭示其演变规律，为进一步研究海洋涡旋的空间推理预测奠定了坚实的基础。

Meso-scale marine eddies with complicated temporal-spatial evolution process were studied. They are expressed quantitatively and then organized as typical-process cases. These eddies were synthetically identified and dynamically tracked by using SSH （Sea Surface Height）, SST （Sea Surface Temperature） and surface horizontal circulation distribution obtained by Global NLOM （Naval Research Laboratory Layered Ocean Model）. Taking the South China sea （SCS） as an example, a case-based database was built by some typical states extracted from each process of meso-scale eddies. Then the GIS （Geographic Information System） temporal-spatial features of all cases in the database were analyzed. The results show that the meso-scale eddies were distributed as a belt style in NE-SE direction in the SCS, and the horizontal moving speed was 3-16 cm/s with an average value of 8.4 cm/s. Most of them moved towards west. These eddies moved towards the NW direction in spring and summer but towards the EW direction in autumn and winter. The meso-scale eddies in the northeastern SCS mainly originated in September-October and January- February the following year. They moved toward NW first, and then turned to SW. Most of the westward movement of the northeastern eddies can＇t be too far. The meso-scale eddies in the central SCS mainly originated in winter and spring, part of which moved toward SW along the slope. Some of anticyclonic eddies moved toward W along the SCS basin. There were only some anticyclonic eddies identified in the southeastern SCS in the study. They moved toward W or WNW. Their intensity and vorticity were weak, but usually they moved a long distance and had a long lifetime. In the southwestern SCS, eddies originated in summer were more than that in winter, most of which appeared in dipole, and usually they moved a short distance.