基于卫星遥感和数值模拟的夏季舟山沿岸上升流研究
发布时间：2019-01-27 11:47
【摘要】：本文基于12年(2003-2014)的卫星遥感数据,分析了夏季舟山沿岸上升流区海表温度(SST)、叶绿素和上升流强度的变化,以及海面风场对上升流强度的影响;进一步,基于Delft3D模型,模拟了 2014年舟山群岛海域的温度、盐度、海流等水文、动力要素,通过控制试验和改变影响因子的敏感性试验,探讨了夏季诱导舟山沿岸上升流的动力机制。卫星遥感数据分析结果表明:不同年份夏季舟山沿岸上升流的强度变化很大,呈现4～5年的周期,分别于2004、2009、2013年达到峰值;夏季偏南风对舟山沿岸上升流区SST的变化影响很大,尤其是7月份,上升流强度与经向风应力呈现较好的线性关系,相关系数高达0.87;上升流区的叶绿素浓度较高,与SST的变化呈现负相关。基于Delft3D数值模型的控制试验与实测站点的潮位吻合良好,海表温度均方根误差在1℃以内,盐度均方根误差在2ppt左右,模拟SST水平分布表明:2014年的夏季舟山沿岸上升流,6月份较弱,7、8月份逐渐加强,9月份明显减弱,与2014年遥感观测的结果基本一致。控制试验结果较为准确,模型能够用来进行上升流研究。同时,本文分别进行了无风与偏北风、无长江径流、改变斜坡地形、无潮4个敏感性数值试验,以探讨诱导夏季舟山沿岸上升流的动力机制。无风与偏北风模拟的结果表明夏季舟山沿岸上升流低温中心仍然存在,上升流强度无风时较偏南风时稍弱,偏北风时较前两种情况下更弱,风场对上升流的形成贡献不大,但综合卫星遥感数据的分析结果,可以得出风场的变化对上升流强度的变化具有显著的影响,其中偏南风有利于夏季舟山沿岸上升流强度的增加,偏北风则会削弱上升流的强度;无长江径流模拟结果表明,舟山上升流强度略有减弱,长江径流对舟山上升流强度有一定的影响;去除海底斜坡地形的数值试验结果表明,在地形平缓的情况下,舟山上升流几乎消失不见,而地形坡度较陡时则能产生明显的上升流现象。由此可见,斜坡地形对舟山上升流有显著的诱导作用;无潮数值试验中,从SST分布上看不到上升流迹象,断面温盐分布上也无明显的等值线抬升现象,表明潮汐对舟山上升流的产生有显著的诱导作用。综上所述,夏季舟山沿岸上升流是在多种动力要素的共同作用下产生的。其中,潮汐和地形的作用较大,风场和径流的作用较小。底层海水在潮流产生的混合效应和斜坡地形的诱导下,向上爬升形成上升流。风场对上升流的形成贡献较小,但对上升流强度的短期与长期变化有较为显著的影响。
[Abstract]:Based on the satellite remote sensing data of 12 years (2003-2014), the variation of (SST), chlorophyll and upwelling intensity in the upwelling zone along Zhoushan coast in summer and the influence of sea surface wind field on the upwelling intensity are analyzed. Furthermore, based on the Delft3D model, the hydrological and dynamic factors such as temperature, salinity and current in the Zhoushan Islands in 2014 were simulated. The dynamic mechanism of induced upwelling along Zhoushan coast in summer is discussed. The results of satellite remote sensing data analysis show that the intensity of the upwelling along Zhoushan coast in summer varies greatly in different years, showing a period of 4 ~ 5 years, which reached its peak in 2009 and 2013, respectively. The southerly wind in summer has a great influence on the variation of SST in the upwelling zone along the Zhoushan coast, especially in July, there is a good linear relationship between the upwelling intensity and the meridional wind stress, and the correlation coefficient is as high as 0.87; The chlorophyll concentration in upwelling region was higher and negatively correlated with the change of SST. The control test based on Delft3D numerical model is in good agreement with the measured tidal level. The root mean square error of sea surface temperature is less than 1 鈩，
本文编号：2416230
[Abstract]:Based on the satellite remote sensing data of 12 years (2003-2014), the variation of (SST), chlorophyll and upwelling intensity in the upwelling zone along Zhoushan coast in summer and the influence of sea surface wind field on the upwelling intensity are analyzed. Furthermore, based on the Delft3D model, the hydrological and dynamic factors such as temperature, salinity and current in the Zhoushan Islands in 2014 were simulated. The dynamic mechanism of induced upwelling along Zhoushan coast in summer is discussed. The results of satellite remote sensing data analysis show that the intensity of the upwelling along Zhoushan coast in summer varies greatly in different years, showing a period of 4 ~ 5 years, which reached its peak in 2009 and 2013, respectively. The southerly wind in summer has a great influence on the variation of SST in the upwelling zone along the Zhoushan coast, especially in July, there is a good linear relationship between the upwelling intensity and the meridional wind stress, and the correlation coefficient is as high as 0.87; The chlorophyll concentration in upwelling region was higher and negatively correlated with the change of SST. The control test based on Delft3D numerical model is in good agreement with the measured tidal level. The root mean square error of sea surface temperature is less than 1 鈩，
本文编号：2416230
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