School of Marine and Environmental Affairs, University of Washington, Seattle, Washington, United States of America.
Applied Physics Laboratory, University of Washington, Seattle, Washington, United States of America.
PLoS One. 2023 Feb 1;18(2):e0280646. doi: 10.1371/journal.pone.0280646. eCollection 2023.
The northern portion of Washington's outer coast-known locally as the Olympic coast-is a dynamic region characterized by seasonal upwelling that predominates during summer interrupted by occasional periods of downwelling. We examined spring-to-fall water temperature records collected along this coast from 2001-2015 from April to October at four nearshore locations (Cape Elizabeth to Makah Bay) that span one degree of latitude and are located within 15 km of the shore. When compared against a long-term climatology created for 2001-2013, seven-day smoothed temperature anomalies of up to 4.5°C at 40 m depth during 2014 and 2015 show short-term warm events lasting 10-20 days. These periods of warming occurred within the well documented marine heatwave in the Northeast Pacific and were about twice the seasonal temperature range in the climatology at that depth. These warm events were strongly correlated with periods of northward long-shore winds and upper ocean currents, consistent with what is expected for the response to downwelling-favorable winds. While our focus a priori was on 2014 and 2015, we also found large positive temperature events in 2013, which were potentially related to the early stage of the marine heatwave, and in 2011, which did not have a documented marine heatwave. This indicates that near-shore short-term warm events occur during periods of large-scale offshore marine heatwave events, but also can occur in the absence of a large-scale marine heatwave event when downwelling-favorable winds occur during the summer/early fall.
华盛顿外海岸的北部地区——当地人称为奥林匹克海岸——是一个充满活力的地区，其特点是季节性上升流，主要在夏季出现，偶尔会出现下降流。我们研究了 2001 年至 2015 年期间从 4 月到 10 月在这条海岸线上从四个近岸地点（伊丽莎白角到马卡湾）收集的春至秋季水温记录，这些地点跨越一个纬度，位于离海岸 15 公里范围内。与 2001-2013 年创建的长期气候数据相比，2014 年和 2015 年 40 米深处长达 7 天的平滑温度异常高达 4.5°C，表明持续 10-20 天的短期暖事件。这些升温期发生在东北太平洋有记录的海洋热浪中，是该深度气候数据中季节性温度范围的两倍左右。这些暖事件与向北的长岸风和上层海洋流的时期密切相关，与预期的下降流有利风的响应一致。虽然我们的重点是 2014 年和 2015 年，但我们也发现 2013 年出现了较大的正温度事件，这可能与海洋热浪的早期阶段有关，2011 年也没有记录到海洋热浪。这表明，近岸短期暖事件发生在大规模海上热浪事件期间，但在夏季/初秋出现下降流有利风时，即使没有大规模的海洋热浪事件，也可能发生近岸短期暖事件。
