Water Table Depth (WTD) NIMS grid Barrow, Alaska 2014

Water table depth (WTD) measurements were taken along the Networked Info-mechanical System (NIMS) grid in Barrow, Alaska during the summer of 2014. The NIMS grid is situated about 200 meters to the north east side of the International Tundra Experiment (ITEX) dry sites. If a uniform representation of the water table within each plot was visible, then a WTD tube was placed there to measure the change in water table throughout the season. For instance if the plot was half saturated and half dry, then that plot was skipped and no tube was placed there. The exact location of WTD tubes are as follows: Between meters 0-1, 2-3, 5-6, 7-8, 9-10, 11-12, 13-14, 15-16, 18-19, 20-21, 24-25, 26-27, 28-29, 30-31, 32-33, 34-35, 36-37, 38-39, 42-43, 44-45, 47-48, & 49-50. A total of 22 WTD tubes were installed into the NIMS grid in Barrow. Measurements were made once a week during the summer snow free period between mid June and mid August. WTD was calculated as the difference between the depth (cm) of the water table above or below the measuring tube (- Values = water above tube, + Values= water level below the height of the tube) and the height of the top of the measuring tube above the ground level. Measurements were not made (NA in data sheet) if there was persistent snow cover, interference or disturbance from other experimental infrastructure, or if water table depth tubes were dry to the upper surface of the permafrost.2014年夏季，在阿拉斯加州巴罗（Barrow）的网络化信息机械系统（Networked Info-mechanical System, NIMS）网格沿线开展了地下水位深度（Water table depth, WTD）测量工作。NIMS网格位于国际冻原实验（International Tundra Experiment, ITEX）干燥样地东北侧约200米处。若某样地内地下水位分布均匀且可被表征，则在此处布设地下水位观测管以监测整个生长季内的地下水位变化。例如，若样地存在半饱和与半干燥的分区，则跳过该样地，不布设观测管。地下水位观测管的确切位置如下：0-1米、2-3米、5-6米、7-8米、9-10米、11-12米、13-14米、15-16米、18-19米、20-21米、24-25米、26-27米、28-29米、30-31米、32-33米、34-35米、36-37米、38-39米、42-43米、44-45米、47-48米及49-50米区间。本次研究总计在巴罗的NIMS网格中安装了22根地下水位观测管。测量工作于夏季无雪期开展，即6月中旬至8月中旬，每周进行一次。地下水位深度的计算方式为：观测管上方或下方的地下水位深度（单位：厘米，负值代表水位高于观测管顶部，正值代表水位低于观测管顶部高度）与观测管顶部距地面高度的差值。若存在持续积雪、其他实验设施的干扰或破坏，或地下水位观测管至永久冻土上层表面均处于干燥状态，则未开展测量，此类情况在数据表中记为NA。