ZEROCALM-2_Active_layer

Active layer is measured c. 400 m south of the runway on a south facing slope at an elevation of 11-22 m a.s.l. Vegetation changes from dry dryas heath at the upper end to a waterlogged Eriophorum fen in the lower end. The site consists of 208 measuring points in a 120 m x 150 m grid (16 almost N-S oriented rows each with 13 points. There are 10 m between every point. Active layer is measured manually using a metal rod. The dataset was iniated in 1996. Measurements are started as soon as the one point is free of snow in the grid. Measurements are repeated every week until only the snow fan on the south-facing slope is left, thereafter measurements are repeated every second week until the upper part of the soil starts to freeze.

活动层（Active layer）的测量点位位于跑道南侧约400米的南向坡，海拔为11至22米（a.s.l.，即海拔标高）。站点植被从坡上端的干生仙女木灌丛（dryas heath）逐渐过渡至坡下端的积水羊胡子草沼泽（Eriophorum fen）。该站点采用120米×150米的网格布设，共设置208个测点，包含16条近乎南北向的样行，每条样行含13个测点，测点间距为10米。活动层厚度采用金属杆进行人工测量。本数据集于1996年启动。当网格内任意一个测点无积雪覆盖时，即开始测量工作；测量频率为每周一次，直至仅南向坡上残留雪扇，此后改为每两周复测一次，直至土壤上层开始冻结。