The Role of Advective Heat Fluxes in Buffering Annual to Interannual Temperature Variability over U.S. Inner Shelves

大陆架内半部的水温通常是冬季寒冷，夏季温暖，与大气表面热通量的年度循环一致。然而，对历史资料的初步分析和对以往区域研究的综合表明，年周期的振幅存在很大的区域差异。例如，八月和二月的平均温差在美国西海岸的大部分地区沿着不到5摄氏度，但在东海岸则在15到20摄氏度之间沿着。虽然地表热量的年循环也存在很大的区域差异，但地表热通量通常不能解释观测到的年循环幅度或区域差异。这两个结果和previousstudies表明，平流热通量是重要的内大陆架，他们往往缓冲响应表面热通量，并导致重要的生物和社会影响。热应力在生物体功能和群落生态学中起着关键作用，并且内部搁板温度的小幅增加或控制它们的过程的改变可能导致群落结构和/或大规模死亡事件的急剧变化。因此，明确了解平流功能如何起到缓冲作用，就能对未来气候情景中具有生态和商业重要性的沿海海洋物种的潜在变化有一定的预测能力。该研究项目旨在了解在年度和年际时间尺度上控制内大陆架水温变化的过程。该项目包括培训一名研究生，这项研究将首次全面研究内大陆架的热量收支，包括其季节周期和年际变化。现有的温度和速度数据集将用于研究如何通过一些可能的冷却源来维持热平衡，这些冷却源包括：因随深度变化的上升流而产生的跨大陆架交换、沿大陆架温度梯度的沿大陆架平流以及因涡流而产生的跨大陆架交换。结果将被合成，以确定热通量分量的相对贡献及其相关过程的不同大陆架地区的美国。 通过分析，将能够评估大陆架环境（例如宽度）与外部强迫（例如表面热通量、风应力）在驱动所观测到的区域温度模式方面的作用。结果将产生新的信息，大陆架内环流，平流在控制或缓和大陆架内加热的作用，以及更广泛的背景下，以前的研究跨大陆架交换在沿海海洋。

Water temperatures over the inner-half of continental shelves are typically cold in winter and warm in summer, consistent with the annual cycle of surface heat fluxes from the atmosphere. However, preliminary analysis of historical data and synthesis of previous regional studies indicate there are large regional differences in the amplitude of the annual cycle. For example, theaverage temperature difference between August and February is less than 5 C along much of the U.S. West Coast, but is between 15 and 20 C along the East Coast. While there are also large regional differences in the annual cycle of surface heat, the surface heat fluxes do not generally account for the observed amplitude of the annual cycle or the regional differences. Both these results and previousstudies indicate that advective heat fluxes are important over the inner shelf and that they tend to buffer the response to surface heat fluxes and lead to important biological and societal implications. Thermal stresses play a key role in both organism function and community ecology, and small increases in inner shelf temperatures or alterations in the processes that control them can lead to dramatic shifts in community structure and/or mass mortality events. Thus, a clear understanding of how buffering by advection functions would allow some predictive capacity for the potential changes in both ecologically and commercially important coastal marine species in future climate scenarios. This research project aims to understand the processes controlling water temperature variations over the inner shelf on annual and interannual timescales. The project involves training of a graduate student.This study will provide the first comprehensive look at the heat budget of the inner continental shelf, including its seasonal cycle and inter-annual variability. Available temperature and velocity data sets will be used to examine how the heat balance can be maintained by a number of possible sources of cooling including: across-shelf exchange due to depth-dependent upwelling, the along-shelf advection of an along-shelf temperature gradient, and the across-shelf exchange due to eddies. The results will be synthesized to determine the relative contributions of heat flux components and their associated processes for the different shelf regions of the continental US. The analysis will enable an assessment of the role of shelf environment (e.g. width) versus external forcing (e.g. surface heat flux, wind stress) in driving the regional temperature patterns observed. The results will yield new information about inner-shelf circulation, the role of advection in controlling or moderating inner-shelf heating, as well as give broader context to previous studies of across-shelf exchange in the coastal ocean.