Cryosphere Inland Water Greenhouse Gases Database (CIWD-GHG)

This is a database called Cryosphere Inland Water Greenhouse Gases Database (CIWD-GHG), which provides spatial-temporally resolved greenhouse gases (CO2, CH4, and N2O) data from cryosphere inland waters (lakes, ponds, reservoirs, rivers, and streams). The dataset was created through a synthesis procedure. To compile the dataset, we conducted searches in various sources including peer-reviewed papers, dissertations, theses, and public data repositories. The searches were conducted using platforms such as Web of Science, Google Scholar, ProQuest Dissertations & Theses Global, China National Knowledge Infrastructure, Arctic Data Center, Zenodo, Environmental Data Initiative, and PANGAEA. The search string is: (methane OR CH4 OR carbon dioxide OR CO2 OR nitrous oxide OR N2O OR greenhouse*) AND (river OR stream OR lake OR pond OR reservoir) AND (Arctic* OR Tibet* OR Greenland OR Antarctic OR glacier* OR permafrost). We ensured completeness by conducting multiple searches before April 2023. We applied a consistent criterion for screening and selecting the searched results. Specifically, we included data on greenhouse gas concentrations or fluxes measured in inland water systems such as streams, rivers, ponds, lakes, and reservoirs that are associated with permafrost or glaciers. The study focused on the cryosphere extent, excluding sites outside this extent. Wetland ecosystems and inland waters in cold regions without glaciers or permafrost were also excluded. Additionally, floodplain lakes connected with river channels were excluded, except for those barely connected with high-closure river channels, which were included as lake sites. Gas concentration data in permanently ice-covered water bodies were not included. We also collected auxiliary data on waterbody physical and chemical characteristics, climate, and land cover to the extent possible. The dataset was divided into two separate files: CryoLake.xlsx and CryoRiver.xlsx. CryoLake.xlsx contained data on lakes, ponds, and reservoirs, while CryoRiver.xlsx contained data on rivers and streams. Each file consisted of four sub-tables: source table (data sources), sites table (sites information), concentration table (concentration data), and flux table (flux data). All sub-tables were linked using unique source IDs, and the sites, concentration, and flux tables were further linked using unique site IDs. The temporal resolution varied, with daily data being the shortest resolution. Sub-daily measurements were averaged to daily data, and data reported in monthly, seasonal, and annual scales were also included. Considering the difficulty in obtaining cryosphere-related GHG data, we included all available data. The spatial resolution primarily focused on the plot scale, although aggregated sites were also included. Detailed spatiotemporal information of the measured data was recorded in the data table for further analysis. Due to regional heterogeneity, we did not have a uniform standard for dividing seasons. Instead, seasons were assigned based on the site descriptions provided in each study.

本数据集命名为冰冻圈内陆水体温室气体数据库（Cryosphere Inland Water Greenhouse Gases Database, CIWD-GHG），收录了冰冻圈内陆水体（湖泊、塘堰、水库、河流与溪流）的时空分辨率温室气体（CO₂、CH₄、N₂O）数据。本数据集通过综合汇编流程构建。为完成数据集汇编，我们检索了多种来源的数据，包括同行评议论文、学位论文以及公共数据仓储。检索工作依托Web of Science、Google Scholar、ProQuest Dissertations & Theses Global、中国知网（China National Knowledge Infrastructure）、北极数据中心（Arctic Data Center）、Zenodo、环境数据倡议平台（Environmental Data Initiative）与PANGAEA等平台开展。检索式为：(methane OR CH4 OR carbon dioxide OR CO2 OR nitrous oxide OR N2O OR greenhouse*) AND (river OR stream OR lake OR pond OR reservoir) AND (Arctic* OR Tibet* OR Greenland OR Antarctic OR glacier* OR permafrost)。我们于2023年4月前开展多次检索以确保数据完整性。我们采用统一的筛选标准对检索结果进行甄别与遴选：具体而言，我们纳入与多年冻土或冰川相关的内陆水体系统（溪流、河流、塘堰、湖泊与水库）中测得的温室气体浓度或通量数据；研究聚焦于冰冻圈分布范围，排除该范围外的站点；同时排除湿地生态系统以及无冰川或多年冻土的寒区内陆水体。此外，与河道连通的泛滥平原湖泊亦被排除，仅纳入与高封闭河道几乎无连通的泛滥平原湖泊，并将其视为湖泊站点。永久冰覆盖水体的气体浓度数据未被纳入。我们还尽可能收集了水体理化特征、气候与土地覆盖等辅助数据。本数据集分为两个独立文件：CryoLake.xlsx与CryoRiver.xlsx。其中CryoLake.xlsx收录湖泊、塘堰与水库相关数据，CryoRiver.xlsx收录河流与溪流相关数据。每个文件包含四个子表：源数据表（source table）、站点表（sites table）、浓度数据表（concentration table）与通量数据表（flux table）。所有子表通过唯一源标识符（unique source IDs）进行关联，站点表、浓度数据表与通量数据表进一步通过唯一站点标识符（unique site IDs）进行关联。数据集的时间分辨率存在差异，日尺度为最精细的时间分辨率。亚日尺度的实测数据均被平均至日尺度数据，同时纳入以月、季、年为尺度的报告数据。考虑到获取冰冻圈相关温室气体数据的难度，我们纳入了所有可获取的数据。空间分辨率以样点尺度为主，同时纳入聚合站点数据。实测数据的详细时空信息均记录于数据表中，以供后续分析使用。由于区域异质性，本研究未采用统一的季节划分标准，而是根据各原始研究中提供的站点描述进行季节分配。