北黄海冷水团锋面日变化特征及其年际变化特征分析

The Yellow Sea Cold Water Mass(YSCWM) is the typical marine phenomenon of China Sea.The new observation in the northeastern part of north YSCWM show that the daily variation near the bottom area is up to 5-8 degree. In the same time, the temperature-salinity chain buoy in the area found daily variation of the depth of thermocline could exceed 15 meters, the synchronous temperature daily variation conld exceed 8 degree in the thermocline. The phenomenon influnce the fishery and cultivation works in the area. This project intend to use advanced investigation equipment-Moving Vessel Proflier(MVP) and high presion bottom temperature-salinity array to design the high time-apcae resolution observing scheme. With the history data and numerical modelling results, this project intend to decribe the daily variability and space distribution of north YSCWM front. The project will also research the interannual variability of the position and intensity of north YSCWM front. Combining the daily and interannual variability of north YSCWM front, we could give the area of north YSCWM front whose daily temperature variation excceed 4 degree and its interannual variability. The mechanism of daily and interannual variability of north YSCWM front will analysis synchronously. The project will provide the theory foundation of the prediction of the front of north YSCWM and provide the scientific support for the marine economics in the area.

黄海冷水团是中国近海最典型的海洋现象之一。最新的观测发现夏季黄海冷水团东北侧锋面区底层温度存在强烈的周日波动，可达5-8度。同时北黄海冷水团跃层深度的日变化幅度也在15米左右，跃层区域温度最大变率近8度，上述海洋现象对该区域的渔业捕捞和养殖生产造成了巨大损失。项目拟应用先进的调查装备-MVP,高分辨率底层温盐阵等，针对北黄海冷水团锋面设计高时空分辨率调查方案，结合历史资料分析和数值模型研究手段，阐明北黄海冷水团锋面的日周期变化特征和分布范围。同时研究黄海冷水团锋面位置和强度的年际变化特征，系统阐述北黄海冷水团锋面区底层温度日变化率大于4度的空间分布范围及其年际变化特征，并研究其影响机制，为黄海冷水团锋面区温盐结构预报奠定理论基础，从而更好服务于该区域海洋经济的发展。

经过4年的工作，项目组针对对黄海冷水团锋面区域的日周期变化设计了海底温度观测阵列和潜标的组合调查方案，并使用MVP对冷水团锋面的精细结构进行了初步调查，对日周期变化的空间分布和有了一个较为系统的认识。同时，对黄海冷水团的年际变化特征开展了系统研究，发现了北黄海冷水团和南黄海冷水团的在近30年间存在降盐、增温趋势，北黄海冷水团锋面存在减弱趋势，数值模式的工作也进一步验证了观测结果。.跃层和锋面的剧烈震荡对区域的生态环境和养殖生产活动将造成重要影响，其长期演变趋势也将为区域的生态环境和养殖环境治理提供新的依据。同时跃层起伏会对海域密度场造成重要影响，而密度的剧烈改变会对潜艇等水下作战平台的姿态保持造成影响，严重的时候回造成断崖现象。本项目的研究研究成果将对水下作战平台的航行安全提供一定的支撑作用。