Atlantic Meridional Overturning Circulation Near 41N from Altimetry and Argo Observations

Updated January 8, 2024 to include estimates through calendar year 2023. These files contain an estimate of the Atlantic Meridional Overturning Circulation (AMOC) volume and heat transports, computed using observations of temperature, salinity and subsurface velocity from the Argo array of profiling floats (DOI: 10.17882/42182 #98126), and satellite-based observations of sea level from altimetry (DOI: 10.48670/moi-00148). The estimates are computed using the techniques of Willis (2010) and Hobbs and Willis (2012). In addition, estimates of wind stress at the surface were estimated from European Center for Medium Range Weather Forecast, ERA5 analysis (DOI: 10.24381/cds.143582cf). Note that in all files, although there are 12 time-steps per year, each time step represents a 3-month average, so the time series is over sampled. The .txt file contains comma separated values of the time series, with 1 header line and the following columns, estimated as in Willis (2010) and Hobbs and Willis (2012): Column 1: Decimal year Column 2: Ekman Volume Transport (Sverdrups) Column 3: Northward Geostrophic Transport (Sverdrups) Column 4: Meridional Overturning Volume Transport (Sverdrups) Column 5: Meridional Overturning Heat Transport (PetaWatts) The file called “trans_Argo_ERA5.nc” contains an estimate of the geostrophic transport as a function of latitude, longitude, depth and time, for the upper 2000 m for latitudes near 41 N in the Atlantic Ocean, estimated as described in Willis (2010). Also included are Ekman Transport and Overturning Transport as functions of time and latitude for this region. The file called “Q_ARGO_obs_dens_2000depth_ERA5.nc” contains estimates of heat transport for these regions based on various assumptions about the temperature of the ocean at depths unmeasured by the Core Argo array (depths below 2000m), estimated as described in Hobbs and Willis (2012). These assumptions are described in the variable “Hpar”. If you use these data please cite: Willis, J. K., and Hobbs, W. R., Atlantic Meridional Overturning Circulation Near 41N from Altimetry and Argo Observations. Dataset access [YYYY-MM-DD] at 10.5281/zenodo.8170366. References: Hobbs, W. R., and J. K. Willis (2012), Midlatitude North Atlantic heat transport: A time series based on satellite and drifter data. J. Geophys. Res., 117, C01008, doi:10.1029/2011JC007039. Willis, J. K. (2010), Can in situ floats and satellite altimeters detect long-term changes in Atlantic Ocean overturning?, Geophys. Res. Lett., 37, L06602, doi:10.1029/2010GL042372. http://www.agu.org/pubs/crossref/2010/2010GL042372.shtml Copernicus Climate Change Service, Climate Data Store, (2018): Sea level gridded data from satellite observations for the global ocean from 1993 to present. Copernicus Climate Change Service (C3S) Climate Data Store (CDS). DOI: 10.24381/cds.4c328c78 (Accessed on 21-Dec-2022) Hersbach, H., et al. (2017): Complete ERA5 from 1940: Fifth generation of ECMWF atmospheric reanalyses of the global climate. Copernicus Climate Change Service (C3S) Data Store (CDS). DOI: 10.24381/cds.143582cf (Accessed on 24-Dec-2022) Wong, A. P. S., et al. (2020), Argo Data 1999–2019: Two Million Temperature-Salinity Profiles and Subsurface Velocity Observations From a Global Array of Profiling Floats, Frontiers in Marine Science, 7(700), doi: https://doi.org/10.3389/fmars.2020.00700 (Accessed on 19-Dec-2022)

本数据集更新于2024年1月8日，补充了截至2023日历年的估算结果。本数据集包含大西洋经向翻转环流（Atlantic Meridional Overturning Circulation, AMOC）的体积输运与热输运估算值，其计算基于Argo剖面浮标阵列获取的温度、盐度及次表层流速观测数据（DOI: 10.17882/42182 #98126），以及卫星高度计获取的海平面观测数据（DOI: 10.48670/moi-00148）。该估算采用Willis（2010）与Hobbs、Willis（2012）提出的技术方法完成。此外，地表风应力的估算数据源自欧洲中期天气预报中心（European Center for Medium Range Weather Forecast）的ERA5再分析资料（DOI: 10.24381/cds.143582cf）。
需注意，所有数据文件中每年均包含12个时间步长，但每个时间步长代表3个月的平均值，因此该时间序列存在过采样情况。
本项目提供的.txt文件以逗号分隔值（CSV）格式存储时间序列数据，包含1行表头，各列估算结果严格遵循Willis（2010）与Hobbs、Willis（2012）的方法定义，各列含义如下：第1列：十进制年份；第2列：埃克曼体积输运（单位：斯维尔德鲁普，Sverdrups）；第3列：北向地转输运（单位：斯维尔德鲁普）；第4列：经向翻转体积输运（单位：斯维尔德鲁普）；第5列：经向翻转热输运（单位：拍瓦，PetaWatts）。
名为"trans_Argo_ERA5.nc"的文件包含大西洋北纬41度附近海域上层2000米的地转输运估算值，该估算值为纬度、经度、深度与时间的函数，计算方法详见Willis（2010）。该文件同时包含该区域埃克曼输运与翻转输运随时间与纬度变化的估算结果。
名为"Q_ARGO_obs_dens_2000depth_ERA5.nc"的文件包含该区域的热输运估算值，其基于对核心Argo阵列未观测到的2000米以深海域海水温度的多种假设，计算方法详见Hobbs与Willis（2012）。相关假设已在变量"Hpar"中进行说明。
若您使用本数据集，请引用如下文献：Willis, J. K. 与 Hobbs, W. R., 《大西洋北纬41度附近基于高度计与Argo观测的经向翻转环流》，数据集访问链接[访问日期：YYYY-MM-DD]：10.5281/zenodo.8170366。
参考文献：
1. Hobbs, W. R. 与 J. K. Willis (2012), 中纬度北大西洋热输运：基于卫星与漂流浮标数据的时间序列. 《地球物理学研究杂志》, 117, C01008, doi:10.1029/2011JC007039.
2. Willis, J. K. (2010), 原位浮标与卫星高度计能否探测到大西洋经向翻转环流的长期变化？《地球物理学研究快报》, 37, L06602, doi:10.1029/2010GL042372. 可访问：http://www.agu.org/pubs/crossref/2010/2010GL042372.shtml
3. 哥白尼气候变化服务中心, 气候数据存储库 (2018): 1993年至今全球海洋卫星观测海平面格点数据. 哥白尼气候变化服务中心（C3S）气候数据存储库（CDS）. DOI: 10.24381/cds.4c328c78（2022年12月21日访问）
4. Hersbach, H. 等. (2017): 1940年起完整ERA5数据集：全球气候第五代ECMWF大气再分析资料. 哥白尼气候变化服务中心（C3S）数据存储库（CDS）. DOI: 10.24381/cds.143582cf（2022年12月24日访问）
5. Wong, A. P. S. 等. (2020), 1999–2019年Argo数据：来自全球剖面浮标阵列的200万条温度-盐度剖面与次表层流速观测数据, 《海洋科学前沿》, 7(700), doi: https://doi.org/10.3389/fmars.2020.00700（2022年12月19日访问）