CCHDO Hydrographic Data Archive, Version 2025-11-01. In CCHDO Hydrographic Data Archive

CCHDO contains hydrographic data collected from research vessels globally. Data are aggregated from science party submissions from programs such as GO-SHIP, WOCE, and CLIVAR aimed at reference-quality data. The data are assembled by cruise into several standard formats (e.g. WHP-Exchange, WOCE, and netCDF), as well as assessed for consistent parameter naming and flags, and known units of measurement. Data are not further quality controlled by CCHDO.

The primary location of the CCHDO dataset is https://cchdo.ucsd.edu/. Snapshots of the CCHDO data and metadata are being deposited periodically for long-term preservation and access at the UC San Diego Library and are therefore also available through this collection. The most recent snapshot can be accessed at the top of the list of collection items.

Data Formats:
Data are available in CF/netCDF, WHP Exchange, COARDS netCDF, and WOCE text formats. CF/netCDF is a netCDF file following the Climate and Forecast metadata conventions available at https://cfconventions.org/, it is specifically using the incomplete multidimensional array representation of profiles defined in section 9.3.2. The WHP Exchange format is a CSV-like format described at https://exchange-format.readthedocs.io/. COARDS netCDF is an older netCDF metadata convention and uses one file per profile. The WOCE text formats, which are defined in Chapter 4 of WOCE Publication 90-1 uses separate formats for discrete and continuous data. Users of WOCE data must also download the Station Summaries, defined in Chapter 3 of WOCE Publication 90-1, for profile time and space information.

File Names:
All the file names in this snapshot have been regularized from what may be available on https://cchdo.ucsd.edu. All file names will start with the expedition identifier called an Expocode followed by an extension that identifies the type of data. Files and data from the same expedition will have the same Expocode. The following is a list of the extensions:

* Bottle
- CF/netCDF: _bottle.nc
- WHP Exchange: _hy1.csv
- COARDS netCDF _nc_hyd_.zip
- WOCE Text: hy.txt
* CTD
- CF/netCDF: _ctd.nc
- WHP Exchange: _ct1.zip
- COARDS netCDF _nc_ctd.zip
- WOCE Text: ct.zip
* Large Volume
- WOCE Text: lv.txt
* Cruise Reports:
- PDF: do.pdf
- text: do.txt
* Station Summaries
- WOCE Text: su.txt

Bottle Data:
The bottle data contains data from the analysis of water samples. While most of these data are from samples collected from Niskin bottle closures, it can also include any other discrete sample that was collected on an expedition. These data also typically include the readings from CTD sensors at the time of the bottle closure. For older data, it may also include readings from reversing thermometers. These data are available in all 4 formats.

CTD Data:
The CTD data contain in situ readings from instruments that were lowered into the ocean. Typically only the data read while the instrument package was being lowered is included. These data are usually grouped into 1 to 2 decibar pressure bins. Data from the major programs (WOCE, CLIVAR, GO-SHIP, GEOTRACES) will have had the sensors calibrated using data from the bottle samples. These data are available in all 4 formats.

Large Volume Sample Data:
Eleven expeditions from WOCE reported separate large volume samples. The large volume samples were done almost exclusively for radiocarbon measurements using a device called a Gerard Barrel. Improved analysis techniques eliminated the need for separate large volume sampling so radiocarbon measurements are integrated with the rest of the bottle data. These data are only available in the WOCE text format.

Cruise Reports:
The cruise reports are narratives of what happened on each expedition. These will include expedition goals, techniques utilized, preliminary data reports, and reports of issues. These reports are often very useful when investigating why some data may look unusual. These reports are available in PDF and text formats. The PDF formats will include figures and images not able to be included with the text versions.

Station Summaries:
Station summaries contain profile information including longitude, latitude, and times. It will contain one row per event and a single profile may have multiple events. The format is defined by chapter 3 of WOCE Publication 90-1. When using WOCE text formatted CTD, Bottle, or Large Volume sample data, these station summaries must also be downloaded.

CCHDO数据集收录了全球范围内科研船舶采集的水文数据。这些数据汇集自全球共享海洋断面观测计划（GO-SHIP）、世界海洋环流实验（WOCE）以及气候变率与可预报性研究计划（CLIVAR）等旨在获取参考级质量数据的项目的科研团队提交的资料。数据按航次整合为多种标准格式（如WHP交换格式（WHP-Exchange）、WOCE格式与网络通用数据格式（netCDF）），同时对参数命名、标记符及标准计量单位的一致性进行核查。CCHDO不会对这些数据进行额外的质量控制。

CCHDO数据集的主访问地址为https://cchdo.ucsd.edu/。CCHDO的数据与元数据快照会定期存入加州大学圣地亚哥分校图书馆以实现长期保存与访问，因此本馆藏也可获取这些快照。最新的快照可在馆藏条目列表顶部获取。

数据格式：
本数据集提供CF/netCDF、WHP交换格式、COARDS netCDF以及WOCE文本格式四类数据。CF/netCDF格式是遵循https://cfconventions.org/公布的《气候与预报元数据规范》的netCDF文件，其具体采用了第9.3.2节定义的剖面不完全多维数组表示法。WHP交换格式是一种类CSV格式，具体规范详见https://exchange-format.readthedocs.io/。COARDS netCDF是一种较旧的netCDF元数据规范，每个剖面对应一个文件。WOCE文本格式由《WOCE第90-1号出版物》第4章定义，该格式为离散数据与连续数据分别设置了不同的子格式。使用WOCE格式数据的用户还需下载《WOCE第90-1号出版物》第3章定义的站点摘要，以获取剖面的时空信息。

文件名规范：
本快照中的所有文件名均已从https://cchdo.ucsd.edu/上的原始命名规则进行了标准化处理。所有文件名均以航次标识符（Expocode）开头，随后附上用于标识数据类型的扩展名。同一航次的文件与数据将使用相同的Expocode。以下为各类扩展名的对应说明：
* 采水器（Bottle）数据
- CF/netCDF格式：后缀为_bottle.nc
- WHP交换格式：后缀为_hy1.csv
- COARDS netCDF格式：后缀为_nc_hyd_.zip
- WOCE文本格式：后缀为hy.txt
* CTD数据
- CF/netCDF格式：后缀为_ctd.nc
- WHP交换格式：后缀为_ct1.zip
- COARDS netCDF格式：后缀为_nc_ctd.zip
- WOCE文本格式：后缀为ct.zip
* 大体积样品数据
- WOCE文本格式：后缀为lv.txt
* 航次报告
- PDF格式：后缀为do.pdf
- 纯文本格式：后缀为do.txt
* 站点摘要
- WOCE文本格式：后缀为su.txt

采水器数据：
采水器数据包含水样分析所得的相关数据。这类数据大多源自尼斯金采水器采集的水样，也可涵盖航次中采集的其他离散水样。此类数据通常还包含采水器闭合时CTD传感器的读数；对于老旧数据，还可能包含颠倒温度计的观测值。采水器数据支持上述四类全部格式。

CTD数据：
CTD数据包含下入海洋的仪器的原位观测读数，通常仅收录仪器下放过程中采集的数据。此类数据通常按1至2分巴的压力区间进行分组。来自WOCE、CLIVAR、GO-SHIP、全球海洋痕量元素与同位素研究计划（GEOTRACES）等主要项目的CTD数据，均已利用采水器样品数据对传感器进行过校准。CTD数据支持上述四类全部格式。

大体积样品数据：
WOCE项目共有11个航次采集了独立的大体积样品。这类样品几乎全部用于使用杰拉德桶（Gerard Barrel）设备开展的放射性碳测量。随着分析技术的改进，现已无需单独采集大体积样品，因此放射性碳测量数据已整合至常规采水器数据中。大体积样品数据仅支持WOCE文本格式。

航次报告：
航次报告为各航次执行情况的纪实文档，内容涵盖航次目标、采用的观测技术、初步数据分析报告以及异常情况记录。在排查部分数据异常的原因时，此类报告通常具有重要参考价值。航次报告提供PDF与纯文本两种格式，其中PDF格式可包含纯文本版本无法展示的图表与图像。

站点摘要：
站点摘要包含剖面的相关信息，包括经度、纬度与时间。每条记录对应一个观测事件，单个剖面可能包含多个事件。其格式由《WOCE第90-1号出版物》第3章定义。当使用WOCE文本格式的CTD、采水器或大体积样品数据时，必须同步下载对应的站点摘要文件。