An Analysis of SSH Ridges and SST Frontal Bands in Mid-Latitude Oceans

智慧价值：月平均海表面温度(SST)锋面概率图像显示，所有主要大洋盆地的中纬度纬向带状分布，经向间隔约400公里。这些波段在视觉上与南太平洋东部海面高度异常的脊线和水深测量相关联。此外，它们在许多年内都是稳定的。导致这些特征的动态目前还不清楚。目前的假设范围从斜压不稳定和地转湍流引起的纬向急流，到由平均流或涡旋相互作用确定的首选涡流路径。该项目的具体目标是：量化平均SSH场中锋面概率的持续带和持续脊线之间的关系；确定SST锋面概率的准纬向带的起源和维持；表征锋面概率场中带位置的年际变化；以及分析海底地形对锋面概率带的影响。观测到的纬向结构的普遍存在、其纬向范围、在时间上的持续性以及在所有盆地和所有季节中的均匀经向尺度表明，它们是海洋基本动力过程的结果。这些构造的特征与深部水深测量之间的紧密对应表明，它们参与了远低于主温跃层的过程。因此，了解它们的起源可能有助于更好地了解海洋的一般环流。更广泛的影响：在该项目过程中，将向海洋界提供从1981年到目前各种空间和时间分辨率的各种卫星SST场的正面数据集。初步工作表明，与锋面带有关的海温异常对海洋和大气的影响。具体地说，这些异常上方的大气水汽含量高于背景。与地质学也有潜在的联系，因为与这些带有关的特征在时间上是持久的--可能在很长一段时间内对海底的沉积和冲刷产生影响。了解纬向条纹的动态和持久性对于理解影响气候的长时间尺度上的海洋输送也很重要，从而有助于我们理解海洋在地球气候中的作用。这也将推动努力将这些海洋过程参数化，以便在粗略耦合的全球气候模式中表现出来。本提案中提出的波段探测算法及其分析提供了重要的尺度信息，可用于全球海洋观测系统的设计和维护。该项目还将支持一名研究生的培训。

Intellectual Merit: Images of monthly averaged sea surface temperature (SST) front probability show zonal bands at mid-latitudes in all major ocean basins with a meridional separation of approximately 400 km. These bands are visually correlated with ridges of sea surface height (SSH) anomaly in the eastern South Pacific and with bathymetry. Furthermore, they are stable over many years. The dynamics giving rise to these features are not understood at present. Current hypotheses range from zonal jets resulting from baroclinic instability and geostrophic turbulence to preferred eddy pathways determined by mean flows or eddy interactions. The specific objectives of this project are: to quantify the relationship between persistent bands of frontal probability and persistent ridges in mean SSH fields; to determine the origin and maintenance of quasi-zonal bands of SST front probability; to characterize the inter-annual variability of the location of bands in the frontal probability fields; and, to analyze the impact of bottom topography on bands of frontal probability. The ubiquity of the observed zonal structures, their zonal extent, their persistence in time and the uniform meridional scale in all basins and all seasons suggests that they result from fundamental dynamic processes in the ocean. The tight correspondence between features in these structures and deep bathymetry suggests that they are involved with processes that extend well below the main thermocline. As such, understanding their origin will likely contribute to a better understanding of the general circulation of the ocean. Broader Impacts: In the course of the project, frontal data sets from a variety of satellite-derived SST fields extending from 1981 to present at a variety of spatial and temporal resolutions will be made available to the oceanographic community. Preliminary work suggests an ocean to atmosphere impact of the SST anomalies associated with frontal bands. Specifically, atmospheric water vapor is higher over these anomalies than the background. There is also a potential connection with geology in that the features associated with the bands are persistent in time - possibly over very long times with impacts on deposition on and scouring of the sea floor. Understanding the dynamics and persistence of the zonal striations will also be important to understanding ocean transports over long timescales affecting climate and thereby benefit our understanding of the ocean role in Earth's climate. This would also motivate efforts for parameterizing these ocean processes for representation in coarse coupled global climate models. The band detection algorithms and the analyses therein, as developed in this proposal, provide important scale information that can be useful in the design and maintenance of global ocean observing systems. This project will also support the training of one graduate student.