Terrestrial water data synthesis for hydrological catchments around the world in the Anthropocene

We here synthesise hydro-climatic data reported by previous studies for 65 hydrological catchments around the world [1-7] for further meta-analysis of how water fluxes of precipitation (P), runoff (R), and actual evapotranspiration (ET) on land change in the Anthropocene epoch, from before to after its start in the 1950's [8]. These water flux changes alter how much water ends up sustaining crops and other plants (evapotranspiration) and how much remains for the lateral water flows (runoff) through the landscape and the societal water uses and ecosystems they support. How this partitioning changes as integral part of global change is key for water and food security, and life on land and below water around the world’s land areas and coasts. To distinguish the impacts of direct human drivers on evapotranspiration and runoff changes based on instrumental data for wide-ranging water, human-activity and climate conditions around the world, the 65 study catchments are divided in two comparative sets. One set includes 52 large catchments, selected from two previous data compilations and studies [1,2] and is in the data files referred to as the world set of catchments. The study periods are 1901–2008 for 21 [2] and 1930–1979 for the other 31 [1] of these catchments. The second set includes 13 catchments selected from previous studies [3-7] of both the water flux changes and associated dominant human drivers of these for time periods that are largely consistent with those for the world set of catchments (within 1901-2016); this is in the data files referred to as the known human-shifted set of catchments. The dominant direct human drivers of water-flux changes in these catchments include expanded/intensified rainfed agriculture (RA), irrigated agriculture (IA), or dams and reservoirs for engineered flow regulation (FR), as listed and cited for each known human-shifted catchment in the data files. For each study catchment, we have quantified and report in the data files long-term average P, R and ET values over the total study period and changes in period-average values between two subperiods within it. The subperiods are 1901–1954 and 1955–2008 for 21 [2], and 1930–1954 and 1955–1979 for the other 31 [1] world catchments, and largely consistent for the known human-shifted catchments [3-7] (as listed in the data files). Each study catchment is also classified as water or energy limited by quantifying the associated Budyko-based aridity index PET/P, where PET is potential evapotranspiration. Average PET is estimated as PET≈325+21T+0.9T² where T is long-term annual and catchment average surface temperature in °C, calculated from monthly temperature data in the previous catchment studies [1-7]. The resulting PET/P index classifies actual ET/P in each catchment as energy limited for average PET/P &lt; 1 or water limited for average PET/P &gt; 1, as listed in the data files. Other catchment information included in the data files, uploaded in both pdf and xlsx formats, include source references, catchment name, area and station ID and continent and latitude location. Overall, this dataset provides a wide-ranging sample of catchment-wise related, water balance-constrained local-regional changes in average P, R and ET under major RA, IA, FR developments (known for the second human-shifted set of catchments [3-7]) and various other human-activity and climate developments around the world from before to after the Anthropocene start in the 1950’s [8].为开展元分析，我们整合了既往研究报道的全球65个水文流域（hydrological catchments）的水文气候数据[1-7]，旨在解析人类世（Anthropocene epoch）时期陆地降水（precipitation, P）、径流（runoff, R）与实际蒸散发（actual evapotranspiration, ET）的水文通量变化——该时期以1950年代为分界[8]。 这些水文通量变化会改变用于维持作物与其他植被的水量（通过蒸散发消耗），以及留存于景观侧向径流、支撑社会用水与生态系统的水量。这种水量分配格局的变化是全球变化的核心组成部分，对全球陆地与海岸带的水安全、粮食安全以及陆地和水下生命均至关重要。 为基于覆盖全球多样水文、人类活动与气候条件的实测数据，厘清直接人类活动驱动力对蒸散发与径流变化的影响，本研究将65个研究流域划分为两组对比数据集。第一组包含52个大型流域，源自两项既往数据汇编与研究[1,2]，在数据文件中被称为全球流域集（world set of catchments）；该组中21个流域的研究时段为1901–2008年[2]，其余31个流域的研究时段为1930–1979年[1]。 第二组包含13个流域，源自既往针对水文通量变化及其主导人类驱动力的研究[3-7]，其研究时段与全球流域集基本一致（1901–2016年区间内）；该组在数据文件中被称为人类活动扰动流域集（known human-shifted set of catchments）。这些流域内水文通量变化的主要直接人类驱动力包括扩张/强化的雨养农业（rainfed agriculture, RA）、灌溉农业（irrigated agriculture, IA），以及用于人工径流调控的水坝与水库（flow regulation, FR），相关信息已在数据文件中为每个人类活动扰动流域逐一列出并标注引用。 针对每个研究流域，我们已量化并在数据文件中公布了全研究时段的长期平均P、R与ET值，以及该时段内两个子阶段的时段平均变化量。对于全球流域集的21个流域[2]，其子阶段为1901–1954年与1955–2008年；其余31个流域[1]的子阶段为1930–1954年与1955–1979年；人类活动扰动流域集的子阶段则与上述时段基本一致[3-7]（详见数据文件）。 我们还通过量化基于布迪科（Budyko）的干旱指数PET/P（PET为潜在蒸散发（potential evapotranspiration, PET）），将每个研究流域划分为水分受限型或能量受限型。潜在蒸散发的长期平均值通过公式PET≈325+21T+0.9T²估算，其中T为长期年际与流域平均地表温度（单位：℃），数据源自既往流域研究的月度温度资料[1-7]。由此得到的PET/P指数可将每个流域的实际ET/P划分为两类：当平均PET/P < 1时为能量受限型，当平均PET/P > 1时为水分受限型，相关分类结果已列入数据文件。 数据文件以PDF和XLSX两种格式上传，其中还包含其他流域信息：来源参考文献、流域名称、面积、站点ID、所在大洲与纬度坐标。 总体而言，本数据集覆盖了全球范围内自1950年代人类世起始前后[8]，在主要RA、IA、FR活动（第二组人类活动扰动流域集[3-7]已明确此类活动）以及其他各类人类活动与气候变化背景下，受水量平衡约束的局地-区域尺度P、R、ET平均变化的多流域样本。