Abstract Oceanographic observations collected at Station P (145°W, 50°N) in the northeast Pacific extend for over six decades, representing one of the longest available records of subsurface ocean water properties. As such, this record is well suited to examine secular trends in properties of the subarctic waters of the North Pacific. In this paper, previously published trends are reviewed and updated, based on a newly compiled dataset for the station. Vertically integrated quantities such as ocean heat content and steric height are examined, as well as local water properties through the water column including temperature, salinity and, in particular, oxygen. Consideration is also given to upper-ocean stratification, along with depths of the mixed layer and isopycnal surfaces. The results provide a comprehensive view of long-term changes to ocean conditions in the deep waters of the subarctic Pacific. Increases in 0/2000 dbar ocean heat content and steric height are evident, due primarily to ocean warming through the upper 500 dbar of the water column. However, about a third of the overall 0/2000 dbar steric height trend is due to halosteric effects. A significant freshening trend is evident through the upper layer to the top of the permanent pycnocline. Significant changes are also found below the permanent pycnocline, in particular warming on isopycnal surfaces along with downward migration of isopycnals. On the other hand, no robust trend emerges in the strength of the stratification associated with the permanent pycnocline, a result that likely has implications for turbulent exchanges between the surface mixed layer and the deep ocean, including the supply of nutrients to the euphotic zone. Statistically significant declines in dissolved oxygen are observed on isopycnals below the pycnocline, down to great depth. Column-integrated dissolved oxygen has declined at a rate of 0.72 mol m−2 y−1, representing a net loss over six decades of 11.7 ± 3.5% in total oxygen content per square metre. This is substantially greater than the global average of 2%, underscoring the northeast Pacific as a region of comparatively rapid deoxygenation. Changes in solubility due to local warming have made only a minor contribution to the observed decline.

中文翻译：

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东北太平洋 P 站水特性的长期趋势：更新分析

摘要 在东北太平洋的 P 站（西经 145 度，北纬 50 度）收集的海洋观测资料延续了 60 多年，是最长的地下海水性质记录之一。因此，该记录非常适合检查北太平洋亚北极水域特性的长期趋势。在本文中，根据新编译的台站数据集，对先前发布的趋势进行了审查和更新。垂直综合量，如海洋热含量和空间高度，以及通过水柱的局部水特性，包括温度、盐度，尤其是氧气，都被检查。还考虑了上层海洋分层，以及混合层和等密度面的深度。结果提供了亚北极太平洋深水海洋条件长期变化的综合视图。0/2000 dbar 海洋热含量和空间高度的增加是明显的，主要是由于通过水柱上部 500 dbar 的海洋变暖。然而，整体 0/2000 dbar 空间高度趋势的大约三分之一是由于卤代效应。从上层到永久斜斜的顶部，明显的清新趋势很明显。在永久密克林下方也发现了显着变化，特别是等密云表面的变暖以及等密云的向下迁移。另一方面，在与永久pycnocline相关的分层强度方面没有出现强劲的趋势，这一结果可能对表层混合层和深海之间的湍流交换产生影响，包括向透光区供应营养物质。在 pycnocline 下方的等密度线上观察到溶解氧的统计显着下降，直至很深。柱集成溶解氧以 0.72 mol m-2 y-1 的速率下降，代表每平方米总氧含量在 60 年间的净损失为 11.7 ± 3.5%。这大大高于 2% 的全球平均水平，突显出东北太平洋是一个脱氧速度相对较快的地区。由于局部变暖引起的溶解度变化对观察到的下降的贡献很小。在 pycnocline 下方的等密度线上观察到溶解氧的统计显着下降，直至很深。柱集成溶解氧以 0.72 mol m-2 y-1 的速率下降，代表每平方米总氧含量在 60 年间的净损失为 11.7 ± 3.5%。这大大高于 2% 的全球平均水平，突显出东北太平洋是一个脱氧速度相对较快的地区。由于局部变暖引起的溶解度变化对观察到的下降的贡献很小。在 pycnocline 下方的等密度线上观察到溶解氧的统计显着下降，直至很深。柱集成溶解氧以 0.72 mol m-2 y-1 的速率下降，代表每平方米总氧含量在 60 年间的净损失为 11.7 ± 3.5%。这大大高于 2% 的全球平均水平，突显出东北太平洋是一个相对较快的脱氧区域。由于局部变暖引起的溶解度变化对观察到的下降的贡献很小。强调东北太平洋是一个相对较快的脱氧区域。由于局部变暖引起的溶解度变化对观察到的下降的贡献很小。强调东北太平洋是一个相对较快的脱氧区域。由于局部变暖引起的溶解度变化对观察到的下降的贡献很小。