The Influence of Coastal-Trapped Waves on the Inner Continental Shelf: Temperature and Circulation Patterns

以前的研究表明，北美西海岸的海平面、沿陆架的速度和水温的大幅波动是由海岸捕获的海浪造成的。这些海浪向极地传播，周期从几天到几周，主要由风的波动驱动，是一种机制，通过这种机制，一个地点的风会影响远处其他地点的沿海海洋。观察到下加利福尼亚州的远程风波动导致南加利福尼亚州海湾的冷暖水团向岸上输送，这对海藻森林的营养供应、幼虫的运输、内部潮汐温度波动的强度以及沿海污染和有害藻华的捕获或冲刷都有影响。这项研究将检验这样一种假设，即在圣巴巴拉海峡和北海峡群岛周围，由下加利福尼亚州风波动产生的沿海困住波到达的陆架压力梯度是环流和温度变化的主要来源。它将回答以下问题：1)下加利福尼亚州的风波动对海岸压力、速度、温度和层结有什么影响？2)点概念如何影响海岸压力、速度和温度波动的传播？3)内潮汐和内孔是否受海岸困波引起的温跃层浅化的影响？这项以过程为导向的研究将利用现有的观测数据，包括：i)18年来的系泊部署，以及ii)从下加利福尼亚州延伸到加利福尼亚州旧金山的卫星风以及沿海温度和海平面数据。它将包括将观测到的海平面梯度与下加利福尼亚州遥远的风进行比较，以及将海岸附近观测到的速度和温度信号与经过验证的由气压梯度驱动的流动的动力学模型进行比较。这些将有助于确定由于沿海困住波的通过而引起的温跃层深度的区域波动是增强还是抑制内潮汐温度波动，并有助于从动力学上了解下加利福尼亚州远风对沿海海洋的影响。圣巴巴拉海峡和北部海峡群岛支持重要的渔业和海藻森林生态系统，并包含几个海洋保护区，实行基于生态系统的管理。下加利福尼亚州风通过海岸围困波浪机制的影响，对于将生物粒子、营养物质和幼虫输送到该地区生产的海带森林生态系统可能是重要的。因此，这项研究将有助于海洋保护区的管理和规划以及其他跨学科研究，例如国家科学基金会资助的圣巴巴拉海岸长期生态研究项目。它还将通过支持一名新的研究人员的女性PI来帮助保持科学的多样性。

Previous studies show that substantial fluctuations in sea level, along-shelf velocity, and water temperature along the West Coast of North America are due to coastal-trapped waves. These waves propagate poleward, have periods of days to weeks, are mainly driven by wind fluctuations, and are a mechanism by which winds in one location influence the coastal ocean in other locations far away. Remote wind fluctuations in Baja California have been observed to cause transport of warm and cold water masses onshore in the Southern California Bight, with implications for nutrient supply to kelp forests, larval transport, strength of internal tidal temperature fluctuations, and trapping or flushing of coastal pollution and harmful algal blooms. Coastal-trapped waves are also suggested to affect the frequency and strength of internal tidal bores all along the West Coast.This study will test the hypothesis that in the Santa Barbara Channel and around the Northern Channel Islands, along-shelf pressure gradients arriving as coastal-trapped waves generated by wind fluctuations in Baja California are a dominant source of variability in circulation and temperature. It will answer the questions 1) What effect do wind fluctuations in Baja California have on coastal pressure, velocity, temperature, and stratification? 2) How does Point Conception affect the propagation of fluctuations in coastal pressure, velocity, and temperature? and 3) Are internal tides and bores affected by thermocline shoaling due to coastal-trapped waves? This process-oriented study will utilize existing observations from i) mooring deployments covering 18 years, and ii) satellite winds and coastal temperature and sea-level data extending from Baja California to San Francisco, California. It will include comparisons of observed sea-level gradients to remote winds in Baja California, and of observed velocity and temperature signals near the coast to proven dynamical models of flow driven by a pressure gradient. These will help determine whether regional fluctuations in thermocline depth due to the passage of coastal-trapped waves enhance or inhibit internal-tidal temperature fluctuations, and lead to a dynamical understanding of the effects of remote winds in Baja California on the coastal ocean.BROADER IMPACTSCoastal-trapped waves occur worldwide, but their effect on water temperature near the shore and cross-shelf and along-shelf circulation is not well-described. The Santa Barbara Channel and Northern Channel Islands support important fisheries and kelp forest ecosystems and contain several Marine Protected Areas under ecosystem-based management. The influence of winds in Baja California via the coastal-trapped wave mechanism is probably important for delivery of biogenic particles, nutrients, and larvae to productive kelp forest ecosystems in the region. Therefore this study will benefit management and planning of marine protected areas as well as other interdisciplinary research such as at the NSF-supported Santa Barbara Coastal Long-Term Ecological Research project. It will also help maintain diversity in the sciences by supporting a female PI who is a new investigator.