来自sap流量测量的全球蒸腾数据：SAPFLUXNET数据库

摘要

植物蒸腾作用将植被水供应生理反应和与陆地-大气界面的水文、能量和碳收支联系起来。然而，尽管蒸腾作用是全球范围内的主要陆地蒸发通量，但其对环境驱动因素的响应目前并未受到很好的观测。本研究中，我们介绍了全球首次液流流量测量（SAPFLUXNET，https://sapfluxnet.creaf.cat/，最后访问日期：2021年6月8日）。我们在一个用R编程语言实现的半自动数据工作流程中对全球贡献者提供的单个数据集的质量进行了协调。数据集包括一个或多个生长季节的树液流和水文气象驱动因素的每日时间序列，以及关于林分特征、植物属性和测量技术细节的元数据。SAPFLUXNET包含202个全球分布的数据集，其中包含174属2714种植物（主要是树木）的液流时间序列。SAPFLUXNET具有广泛的生物气候覆盖范围，林地/灌木丛和温带森林生物群落尤其具有代表性（80 % 数据集）。这些测量涵盖了林分的各种结构特征和植物大小。数据集涵盖了1995年至2018年，50%的数据集时间跨度至少为3年。大多数数据集都有相应的辐射和蒸汽压亏缺数据，56%的数据集有现场土壤含水量数据。 许多数据集来自占据90或更多的总林分断面积的物种，允许在不同的生态环境中估算林分蒸腾作用。SAPFLUXNET增加了现有的植物特征数据集、生态系统通量网络和遥感数据，以帮助我们更好地了解植物用水、植物对干旱的反应和生态水文过程。可从Zenodo存储库免费获得SAPFLUXNET版本0.1.5(https://doi.org/10.5281/zenodo.3971689；Poyatos et al., 2020a)）。“sapfluxnetr”R软件包——旨在访问、可视化和处理SAPFLUXNET数据—可从CRAN获得。

Global transpiration data from sap flow measurements: the SAPFLUXNET database

Abstract

Plant transpiration links physiological responses of vegetation to water supply and demand with hydrological, energy, and carbon budgets at the land–atmosphere interface. However, despite being the main land evaporative flux at the global scale, transpiration and its response to environmental drivers are currently not well constrained by observations. Here we introduce the first global compilation of whole-plant transpiration data from sap flow measurements (SAPFLUXNET, https://sapfluxnet.creaf.cat/, last access: 8 June 2021). We harmonized and quality-controlled individual datasets supplied by contributors worldwide in a semi-automatic data workflow implemented in the R programming language. Datasets include sub-daily time series of sap flow and hydrometeorological drivers for one or more growing seasons, as well as metadata on the stand characteristics, plant attributes, and technical details of the measurements. SAPFLUXNET contains 202 globally distributed datasets with sap flow time series for 2714 plants, mostly trees, of 174 species. SAPFLUXNET has a broad bioclimatic coverage, with woodland/shrubland and temperate forest biomes especially well represented (80 % of the datasets). The measurements cover a wide variety of stand structural characteristics and plant sizes. The datasets encompass the period between 1995 and 2018, with 50 % of the datasets being at least 3 years long. Accompanying radiation and vapour pressure deficit data are available for most of the datasets, while on-site soil water content is available for 56 % of the datasets. Many datasets contain data for species that make up 90 % or more of the total stand basal area, allowing the estimation of stand transpiration in diverse ecological settings. SAPFLUXNET adds to existing plant trait datasets, ecosystem flux networks, and remote sensing products to help increase our understanding of plant water use, plant responses to drought, and ecohydrological processes. SAPFLUXNET version 0.1.5 is freely available from the Zenodo repository (https://doi.org/10.5281/zenodo.3971689; Poyatos et al., 2020a). The “sapfluxnetr” R package – designed to access, visualize, and process SAPFLUXNET data – is available from CRAN.