摘要: |
根据黄海1977年5月至1981年11月逐月大面温度、盐度和溶解氧调查资料,采用旋转经验正交函数(REOF)、调和分析和延迟相关分析等方法,分析了黄海表观耗氧量(AOU)场季节循环时空模态与机制.黄海年平均表观耗氧量场表层至30 m层为富氧状态;底层为贫氧状态,涌升流、涡旋流对浅层年平均表观耗氧量场水平分布有显著影响,生物活性组分(BAC)耗生氧作用是影响年平均表观耗氧量场水平与垂直差异的主要因素.黄海表观耗氧量场季节循环主要有两种时空模态:第一模态中涌升流、涡旋流、径向风应力、黄海暖流、沉积物需氧(SOD)以及营养盐调控的生物活性组分耗生氧作用季节变化是主要影响因素, 模态空间分量为三层垂直结构分布,模态时间分量季节变化位相为自表层向深层与自底层向上层传播两种形态;第二模态中涡旋流、涌升流、纬向风应力以及营养盐调控的生物活性组分耗生氧作用季节变化是主要影响因素, 模态空间分量为准四层垂直结构分布,模态时间分量季节变化位相为自表层至30 m层同步季节变化与自30 m层向底层传播两种形态.两种模态时间分量中周期分量是主要分量,贫、富氧期准对称季节分布.增氧过程多数出现在贫氧期,使得贫氧期向富氧期转变,耗氧过程多数出现在富氧期,使得富氧期向贫氧期转变,由此形成表观耗氧量模态季节周期循环过程.黄海春夏季溶解氧垂直最大值现象并不是物理生物过程同步季节作用的结果,而是显著垂直差异的物理生物化学分量连续季节演变的综合作用结果. |
关键词: 物理海洋学 表观耗氧量场 季节循环 时空模态 REOF分析 黄海 |
DOI:10.3969/J.ISSN.2095-4972.2016.03.002 |
|
基金项目:山东省海洋生态环境与防灾减灾重点实验室资助项目(2011011);海洋溢油鉴别与损害评估技术国家海洋局重点实验室资助项目(2015010) |
|
Mechanism and spatio temporal modes on the seasonal cycle of apparent oxygen utilization fields in the Yellow Sea |
SHI Qiang |
(Shandong Province Key Laboratory of Marine Ecological Environment and Disaster Prevention and Mitigation, Qingdao 266033,China;North Chinas Sea Environmental Monitoring Center, State Oceanic Administration, Qingdao 266033,China;Key Laboratory of Marine Spill Oil Identification and Damage Assessment Technology, State Oceanic Administration, Qingdao 266033,China) |
Abstract: |
Based on the monthly dataset of the temperature, salinity and dissolved oxygen (DO) from May 1997 to November 1981 of the Yellow Sea, the mechanism and spatiotemporal modes on the seasonal cycle of apparent oxygen utilization (AOU) field in the Yellow Sea were studied with methods of Rotated Empirical Orthogonal Function (REOF), harmonic analysis and the delay correlation analysis. The results show that the annual mean AOU field in the Yellow Sea is in oxic state from surface to 30 meters layer, while the bottom is in anoxic state. Upwelling and vortex flow have significant influence on the horizontal distribution of annual mean AOU field in the shallow layer, and oxidationphotosynthesis of biological active components (BAC) is the main factor which affects the vertical difference of annual mean AOU field.The seasonal cycle of AOU field in the Yellow Sea is divided into two main kinds of spatiotemporal modes. For the first mode, upwelling, vortex flow, meridional wind stress, the Yellow Sea warm current, Sediment Oxygen Demand (SOD) and oxidationphotosynthesis of BAC regulated by nutrients are main influence factors. The spatial component of modes has a vertical structure of 3 layers, and the seasonal variation phase of time component of modes can be divided into 2 forms, including spread from the surface to the deep layer and from the bottom to the upper layer. For the second modes, vortex flow, upwelling, zonal wind stress and oxidationphotosynthesis of BAC are main influence factors. The spatial component of modes has a vertical structure of 4 layers, and the seasonal variation phase of time component of modes can also be divided into two forms, including synchronous seasonal variation from surface to 30 meters layer and spread from 30 meter layer to the bottom. Periodic component is the main component in time components of both modes. The anoxic and oxic stages show a quasisymmetric seasonal distribution. Oxygen increase process often occurs in anoxic stage, and makes the transition from anoxic stage to oxic stage. By contrast, Oxygen consumption process often occurs in oxic stage, and turns oxic stage to anoxic stage forming the seasonal period cycle of AOU mode. The phenomenon of DO vertical maximum in spring and summer in the Yellow Sea is the result of comprehensive effects of continuous seasonal evolution in physical, biological and chemical components which have significant vertical differences, rather than seasonal synchronization of physical and biological processes. |
Key words: physical oceanography apparent oxygen utilization field seasonal cycle spatio temporal mode REOF analysis Yellow Sea |