Relation between sea level and bottom pressure and the vertical dependence of oceanic variability
Relation between sea level and bottom pressure and the vertical dependence of oceanic variability
复制标题
海平面和底部压力之间的关系以及海洋变化的垂直依赖性
DOI：
10.1029/2006gl028588
复制
发表时间：
2007
影响因子：
5.2
通讯作者：
D. Stammer
中科院分区：
文献类型：
--
作者：
N. Vinogradova;R. Ponte;D. Stammer
利用实际强迫下的环流模式的长（50年）模拟，研究了大尺度海平面和底压变率之间的关系。利用导纳和相干分析来表征海底压力和海平面之间的关系，并将其作为周期、水平空间尺度和位置的函数。在模式格网尺度（1°）上，除热带地区外，在<30天的周期内，底部压力基本上与海平面相当。这种等效性在较长时间内（~ 100天）仍然成立，但仅在高纬度（60°左右）和浅深度（<200米）。在其他地方，底部压力和海平面场可能有很大的不同。结果表明，随着纬度和空间尺度的降低，斜压信号的重要性增加，在许多亚热带和中纬度地区存在明显的季节内和较长时间的斜压信号。无论位置和空间尺度如何，年际变率明显是斜压的。研究结果对卫星测高和重力资料的解释和处理及其同化到数值模式具有广泛的意义。
The relation between large‐scale sea level and bottom pressure variability is studied using long (50‐yr) simulations of a general circulation model under realistic forcing. Admittance and coherence analyses are used to characterize the bottom pressure and sea level relationship as a function of period, horizontal spatial scale, and location. At the model grid scale (1°), bottom pressure is found to be essentially equivalent to sea level at periods <30 days, except in the tropics. This equivalence still holds for longer periods (∼100 days), but only at high latitudes (>60°) and in shallow depths (<200 m). Elsewhere, bottom pressure and sea level fields can differ significantly. Results indicate an increase of the importance of baroclinic signals with decreasing latitude and spatial scale, with significant baroclinic signals at intra‐seasonal and longer periods present in many subtropical and mid‐latitude regions. Variability is clearly baroclinic at inter‐annual periods, regardless of location and spatial scale. Results have broad implications for the interpretation and processing of both satellite altimetry and gravity data and for their assimilation into numerical models.