Interannual Variability of Winter-Spring Temperature in the Middle Atlantic Bight: Linkages to Large-Scale Atmospheric and Oceanic Changes

美国东北部的沿海海洋，包括缅因州湾和中大西洋湾，是一个充满活力和高生产力的系统，支持经济上重要的商业渔业。2012年，该区域的海洋温度经历了一次极端变暖事件，对沿海生态系统和商业渔业产生了巨大影响。因此，了解该区域海洋温度的逐年变化，特别是2012年变暖等极端变化，将为生态系统管理提供必要的科学依据，从而对商业捕鱼业产生重要的经济影响。该项目研究大尺度大气和海洋过程在中大西洋湾冬春温度年际变化中的作用，重点是极端温暖和寒冷的年份。 调查人员一直在与国家海洋渔业局的几位科学家讨论这项研究，并计划与他们分享结果。调查人员还将与罗得岛的商业渔业研究基金会密切联系，将结果传达给东北部的商业渔业，并参加研讨会，讨论东北部最近极端年际变化的管理影响。最后，调查人员已经并将继续向公众介绍他们的工作。这项研究的总体目标是更好地了解大尺度大气/海洋过程和美国东北部大陆架年际温度异常之间的机械联系，最终目标是确定极端温度事件的有用预测因子。最近的研究表明，北极变暖增加了极地急流的南北幅度，降低了风速，导致中纬度地区的天气系统移动缓慢，极端事件发生的可能性增加。最近的一项案例研究确定了2011-2012年异常暖冬期间中大西洋湾大陆架大气急流变异与海洋温度异常之间的直接联系。这项研究将把这个案例研究从一个冬天扩展到一个更长的时期，有多个极端温暖/寒冷的冬春季，以解决以下科学问题。美国东北部沿海海洋对气候系统这种极端的逐年变化的反应是什么？在多大程度上是由于大尺度大气强迫，例如，急流变率？海洋过程与大气过程的相对贡献是什么？为了更好地了解大气和海洋过程的相对重要性，将根据观测和数值模拟进行详细的局部海洋热量收支分析。然后，调查人员将探讨与大陆架上空温度异常有关的每个热收支项的年际变化与大规模大气/海洋环流之间的联系。分析将侧重于冬春时期，这一时期的年际异常最大。这也是2012年极端温暖异常和2014年初创纪录低温发生的季节性时间框架。

The coastal ocean off the northeastern U.S. encompassing the Gulf of Maine and the Middle Atlantic Bight is a dynamic and highly productive system supporting economically important commercial fisheries. The ocean temperature in this region experienced an extreme warming event in 2012, which greatly impacted the coastal ecosystem and commercial fisheries. Therefore, understanding year-to-year variability of ocean temperature in this region, especially extreme change such as the 2012 warming, would provide the scientific basis necessary for ecosystem management and thus has important economic impacts for the commercial fishing industry. This project investigates the roles of large-scale atmospheric and oceanic processes in the interannual variability of winter-spring temperatures in the Middle Atlantic Bight, with a focus on the extreme warm and cold years. The investigators have been discussing this research with several scientists in the National Marine Fisheries Service and plan to share the results with them. The investigators will also be in close contact with the Commercial Fisheries Research Foundation in Rhode Island to communicate the results to the commercial fishing industry in the Northeast and participate in workshops dealing with management implications of the recent extreme interannual variability in the Northeast. Finally, the investigators have been, and will continue, presenting their work to the general public. The overall objective of this research is to better understand the mechanistic links between the large-scale atmospheric/oceanic processes and the interannual temperature anomalies on the Northeast U.S. Shelf, with an ultimate goal of identifying useful predictors of extreme temperature events. Recent studies indicate that Arctic warming increases the north-south amplitude of the polar jet stream and reduces its wind speed, resulting in slower-moving weather systems in mid-latitude regions and a higher probability of extreme events. A recent case study identified a direct link between the atmospheric jet stream variability and ocean temperature anomalies on the shelf in the Middle Atlantic Bight during the unusually warm winter of 2011-2012. This research will extend this case study from one winter to a longer period with multiple extreme warm/cold winter-springs to address the following scientific questions. What is the response of the coastal ocean in the northeastern U.S. to such extreme year-to-year variability of the climate system? To what extent is the interannual variability of temperature in the Middle Atlantic Bight due to the large-scale atmospheric forcing, e.g., jet stream variability? What are the relative contributions from oceanic processes versus atmospheric processes? To better understand the relative importance of the atmospheric and oceanic processes, a detailed local ocean heat budget analysis will be carried out based on both the observations and numerical simulations. The investigators will then explore the links between the interannual variability of each heat budget term associated with the temperature anomalies over the continental shelf and the large-scale atmospheric/ocean circulation. The analysis will focus on the winter-spring period, when inter-annual anomalies are the largest. This is also the seasonal time frame when the extreme warm anomaly in 2012 and the record-low temperatures in early 2014 occurred.