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.

本数据集的冻土活动层（Active layer）测量点位位于跑道以南约400米的南向坡地，海拔范围为11~22米。该区域植被呈梯度变化：坡上端为干生仙女木灌丛，坡下端则为积水羊胡子草（Eriophorum）沼泽。研究区在120米×150米的网格内布设了208个测量测点，该网格包含16条近似南北走向的样行，每条样行设有13个测点，测点间距为10米。冻土活动层采用金属杆进行人工测量。本数据集始建于1996年，当网格内任意一处测点无积雪覆盖时即启动当季测量工作；测量频率为每周一次，直至仅南向坡地残留雪扇，此后改为每两周测量一次，直至土壤上层开始冻结。