Vegetation Warming Experiment: 15N Uptake Experiment Inorganic Nitrogen and Phosphorus on Resins, Utqiagvik (Barrow), Alaska, 2018

This dataset consists of inorganic ammonia, nitrate, and phosphate bound to anion and cation binding resins deployed from July through September 2018 in the surface soils of vegetation warming experiment enclosures and paired control plots. Vegetation warming chambers (Zero Power) were deployed on the Barrow Environmental Observatory (BEO), Utqiagvik, Alaska. These chambers (Figure 1) consistently elevated air temperatures by approximately 4°C using a self-venting system described by Lewin et al (2017). Five chambers were deployed from June 17, 2018 to September 24, 2018 on the BEO within a 1 km2 area centered on 71.275N, -156.641W. Each chamber was co-located with an ambient plot where temperatures were not manipulated on patches of tundra containing the target species Arctagrostis latifolia. An intensive field campaign in late July investigated the impact of warming had on A. latifolia biomass, chemistry, and uptake of 15N labeled ammonia that was injected into the surface soils for one week. Initial measurements were taken on July 21, 2018. Harvest occurred on July 27, 2018. Water-extractable nutrients in soils were measured in July following harvests of A. latifolia plants and underlying soils. Availability of ammonia, nitrate, and phosphate throughout the growing season was measured by extracting nutrients bound to anion and cation binding resins deployed from July through September. Environmental variables (thaw depth, surface soil temperatures, surface soil moisture) were measured. Leaf traits and root traits of A. latifolia were also measured. Included is one *.csv data file and one *.pdf user guide. The Next-Generation Ecosystem Experiments: Arctic (NGEE Arctic), was a research effort to reduce uncertainty in Earth System Models by developing a predictive understanding of carbon-rich Arctic ecosystems and feedbacks to climate. NGEE Arctic was supported by the Department of Energy's Office of Biological and Environmental Research. The NGEE Arctic project had two field research sites: 1) located within the Arctic polygonal tundra coastal region on the Barrow Environmental Observatory (BEO) and the North Slope near Utqiagvik (Barrow), Alaska and 2) multiple areas on the discontinuous permafrost region of the Seward Peninsula north of Nome, Alaska. Through observations, experiments, and synthesis with existing datasets, NGEE Arctic provided an enhanced knowledge base for multi-scale modeling and contributed to improved process representation at global pan-Arctic scales within the Department of Energy's Earth system Model (the Energy Exascale Earth System Model, or E3SM), and specifically within the E3SM Land Model component (ELM).

本数据集包含2018年7月至9月间，部署于植被增温实验围栏及配对对照样地表层土壤中的阴离子、阳离子结合树脂所吸附的无机氨、硝酸盐与磷酸盐。
植被增温箱（零功率（Zero Power））部署于阿拉斯加州乌特恰维克（Utqiagvik）的巴罗环境观测站（Barrow Environmental Observatory, BEO）。该类增温箱（图1）采用Lewin等人2017年报道的自通风系统，可将空气温度稳定提升约4℃。
2018年6月17日至9月24日期间，在以71.275°N、-156.641°W为中心的1平方千米范围内，于BEO站点共部署5个增温箱。每个增温箱均配套设置了未进行温度调控的原生环境对照样地，样地内为包含目标物种宽叶羊草（Arctagrostis latifolia）的苔原斑块。
2018年7月末开展了集中野外观测，以探究增温对宽叶羊草生物量、化学组成以及对注入表层土壤为期1周的¹⁵N标记氨的吸收效果的影响。初始测量于2018年7月21日完成，样品采集于2018年7月27日进行。
在采集宽叶羊草植株及下层土壤后，于同年7月对土壤中水提取态营养物质进行了测定。通过提取2018年7月至9月间部署的阴离子、阳离子结合树脂所吸附的营养物质，对整个生长季内氨、硝酸盐与磷酸盐的生物有效性进行了监测。同时测定了冻融深度、表层土壤温度、表层土壤湿度等环境变量，并对宽叶羊草的叶片性状与根系性状进行了测量。
本数据集包含1个*.csv数据文件与1份*.pdf用户指南。
下一代生态系统实验：北极（Next-Generation Ecosystem Experiments: Arctic, NGEE Arctic）项目旨在通过构建富碳北极生态系统的预测性认知及其对气候的反馈机制，降低地球系统模型的不确定性。该项目由美国能源部生物与环境研究办公室资助。
NGEE Arctic项目设有两个野外研究站点：1）位于阿拉斯加州乌特恰维克（旧称巴罗）附近北坡的巴罗环境观测站北极多边形苔原沿海区域；2）阿拉斯加州诺姆以北苏厄德半岛不连续多年冻土区的多处区域。
通过观测、实验与现有数据集综合分析，NGEE Arctic为多尺度建模提供了更完善的知识库，并推动了美国能源部地球系统模型（能源极端尺度地球系统模型（Energy Exascale Earth System Model, E3SM），尤其是其陆面模型组件（ELM））在全球泛北极尺度下的过程表征精度提升。