The impact of drying and warming on ecosystem carbon balance: weekly thaw depth data from the DryPEHR project, Healy AK, 2011

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 weekly ground thaw measurements.

本研究依托联合干湿增温实验（DryPEHR）解答以下三项科学问题：
1. 生态系统干旱化、增温及冻土融化是否会引发碳从生态系统向大气的净释放或碳吸收？
2. 占土壤碳库主体的老碳的分解过程是否会影响生态系统的碳流失？
3. 干旱化与增温会如何作用于植物群落与生态系统属性？

该实验与永久冻土碳实验加热研究（Carbon in Permafrost Experimental Heating Research, CiPEHR）项目共址，选址于阿拉斯加山脉山麓、阿拉斯加州希利镇附近的高地苔原野外监测站点。本实验的增温处理方案为：生长季利用开顶箱（open top chambers, OTC）实现空气温度增温（约1℃），并在积雪期通过雪栅栏实现土壤‘增温’。干旱化处理则通过自动抽水系统降低干旱样地的地下水位实现。土壤增温实验始于2008年，而开顶箱布设与干旱化处理均于2011年启动。本数据集包含每周一次的土壤解冻监测数据。