The impact of drying and warming on ecosystem carbon balance: Half-hourly soil moisture and temperature data from the DryPEHR project, Healy AK, 2010-2013

This drying and warming experiment addresses the following questions: 1) Does ecosystem drying, warming and permafrost thaw cause a net release or uptake of C from the ecosystem to the atmosphere?, 2) Does the decomposition of old C that comprises the bulk of the soil C pool influence ecosystem C loss? 3) How do drying and warmign affect plant communities and ecosystem properties? We are answering these questions using a combined warming and drying experiment (DryPEHR), which is situated with the Carbon in Permafrost Experimental Heating Research (CiPEHR) project and located in an upland tundra field site near Healy, Alaska in the foothills of the Alaska Range. Warming treatment here refers to growing season air temperature warming (~1C) using open top chambers (OTC) combined with soil 'warming' using snow fences during the snow covered months. Drying is achieve using an automated pumping system that lowers the water table in the dry plots. Soil warming began in 2008; OTCs and drying in 2011. This data set includes half-hourly values of surface moisture content (gravimetric, 0-5cm), depth-integrated soil moisture (volumetric, 0-20 cm), and soil temperature in winter warming and summer warming, drying, and control treatment plots at DryPEHR.

本干湿与增温实验旨在解答以下科学问题：1）生态系统的干旱化、增温与冻土融化，是否会引发碳从生态系统向大气的净释放或净吸收？2）占土壤碳库主体的老旧碳的分解过程，是否会对生态系统碳流失产生影响？3）干旱化与增温会如何影响植物群落与生态系统属性？本研究依托联合增温与干旱实验平台（DryPEHR）解答上述问题，该平台与冻土碳实验增温研究（Carbon in Permafrost Experimental Heating Research, CiPEHR）项目共址，设于阿拉斯加山脉山麓、阿拉斯加州希利附近的高地苔原野外样地。本实验的增温处理方案为：在生长季利用开顶式气室（Open Top Chambers, OTC）实现空气温度增温（约1℃），并在积雪期通过雪栅实现土壤增温。干旱化处理则通过自动化抽水系统降低干旱样地的地下水位。土壤增温实验始于2008年，而开顶式气室安装与干旱化处理则于2011年启动。本数据集包含DryPEHR平台各处理样地（冬季增温、夏季增温、干旱化与对照组）的半小时级观测数据，指标包括：0-5cm土层重量法地表土壤含水量、0-20cm土层体积法深度整合土壤含水量，以及土壤温度。