Inter-annual Bering Strait Volume Transport in the Warmer Water Months from Satellite Altimeter Data, 1993 - 2020

Abstract: The work done on this project is described in the Final Report for NSF Award 1740756 and the associated manuscript (see the file Sangmanee_ClarkeJPOmanuscript.pdf submitted to the Arctic Data Center) “Interannual Variability and Trend of the Bering Strait Throughflow Gleaned from Satellite Altimeters” that has been accepted for publication in the Journal of Physical Oceanography. All data in this project are seasonal anomalies, i.e., the mean seasonal value has been subtracted from the data to assess the year-to-year variability. Data related to this project are listed in the following 9 CSV files. The data include:“01_Seasonal_BSt_SSH.csv”, the anomalous July-August-September (JAS), August-September-October (ASO), September-October-November(SON), and July-August-September-October (JASO) Seasonal Satellite Sea Surface Heights in 17 Clusters at the Northern End of Bering Strait. “02_Seasonal_BSt_Transport.csv”, the anomalous volume transports through the Bering Strait 50 meter(m)-depth channel calculated from the 10 western-most clusters. The next 7 Sea Surface Height (SSH) clusters in shallower water east of the 50m-deep Bering Strait channel had negligible transport. Near the coast we were able to use the 17th SSH cluster, interpolated Alaskan coastal sea level between Nome and Red Dog Dock and geostrophic balance to estimate the JAS, ASO, SON, and JASO anomalous transport of the fresher water Alaskan Coastal Current (ACC) which hugs the coast. An explanation of how we did this is in section 3d of Sangmanee_ClarkeJPOmanuscript.pdf, and the relevant data for the calculation and the transports are in the data set titled “03_Seasonal_ACC_Transport.csv”. In order to understand the physical cause of the transport through the strait, Arrested Topographic Wave (ATW) theoretical calculations of anomalous JAS, ASO, SON and JASO wind-driven sea level at stations on the Russian Arctic shelf and on the Bering Sea shelf were done as described respectively in sections 6b and section 7 of Sangmanee_ClarkeJPOmanuscript.pdf. The observational and theoretical sea levels for the seasons JAS, ASO, SON and JASO for the Russian Arctic shelf were reported as required in four data sets, one each for the observed sea levels for the eastern (“04_01_Observed_Russian_SLH_E”) and western hemisphere (05_01_Observed_Russian_SLH_W) as well as theoretical sea levels for the eastern ("04_02_Theoretical_Russian_SLH_E") and western hemisphere (“05_02_Theoretical_Russian_SSH_W.csv”). Observed data needed for the JAS, ASO, SON and JASO Bering Sea calculations are given in "06_01_Observed_Alaskan_SSH" and the theoretical results themselves are given in "06_01_Observed_Alaskan_SSH" . All latitude and longitude coordinates used in the “boxes” below are in degrees with degrees latitude North and degrees longitude East being positive.

摘要：本项目的相关研究工作已收录于美国国家科学基金会（National Science Foundation, NSF）资助项目编号1740756的最终报告，以及提交至北极数据中心（Arctic Data Center）的关联手稿《基于卫星高度计数据探究白令海峡通流量的年际变化与趋势》（Sangmanee_ClarkeJPOmanuscript.pdf），该手稿已被《物理海洋学杂志》（Journal of Physical Oceanography）接收待刊。本项目所用全部数据均为季节距平（seasonal anomalies），即通过从原始数据中扣除平均季节值以评估年际变化。本项目相关数据包含于以下9个CSV文件中："01_Seasonal_BSt_SSH.csv"存储白令海峡北端17个聚类的异常季平均卫星海面高度（Sea Surface Height, SSH）数据，涵盖7-8-9月（JAS）、8-9-10月（ASO）、9-10-11月（SON）及7-8-9-10月（JASO）四个时段；"02_Seasonal_BSt_Transport.csv"存储基于最西侧10个聚类计算得到的、白令海峡50米水深水道的异常体积输运量，白令海峡50米水道东侧浅水区的其余7个海面高度聚类的输运量可忽略不计。针对近岸区域，研究团队利用第17个海面高度聚类数据、诺姆（Nome）与红狗码头（Red Dog Dock）之间插值得到的阿拉斯加沿岸海平面数据，结合地转平衡，估算了紧贴海岸的阿拉斯加沿岸流（Alaskan Coastal Current, ACC）的淡水组分在JAS、ASO、SON、JASO四个时段的异常输运量，相关计算方法详见Sangmanee_ClarkeJPOmanuscript.pdf的第3d节，计算所需的关联数据及输运量结果存储于数据集"03_Seasonal_ACC_Transport.csv"。为探究海峡输运的物理成因，研究团队分别依据Sangmanee_ClarkeJPOmanuscript.pdf的第6b节与第7节所述方法，针对俄罗斯北极陆架与白令海陆架站点的风驱异常JAS、ASO、SON、JASO海平面，开展了停滞地形波（Arrested Topographic Wave, ATW）理论计算。俄罗斯北极陆架各季节的观测与理论海平面数据分为4个数据集：东半球观测海平面（"04_01_Observed_Russian_SLH_E"）、西半球观测海平面（"05_01_Observed_Russian_SLH_W"）、东半球理论海平面（"04_02_Theoretical_Russian_SLH_E"）以及西半球理论海平面（"05_02_Theoretical_Russian_SSH_W.csv"）。白令海各季节计算所需的观测数据收录于"06_01_Observed_Alaskan_SSH"，对应的理论计算结果同样存储于该数据集。下文所有"区域框"中使用的经纬度坐标均以度为单位，北纬与东经为正方向。