Active layer is measured on a welldrained white arctic bell-heather, just north of the Climate station. The site consist of 121 measuring points in a 100m x 100 m grid (11 almost N-S oriented rows each with 11 points). There are 10 m between every point. The grid nodes are numbered from 1-121. 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 all grid nodes are snow free, thereafter measurements are repeated every second week until the upper part of the soil starts to freeze.