The forest-tundra ecotone is the transition zone between the boreal forest and Arctic tundra. This region is undergoing rapid changes and in particular vegetation growth and expansion. In situ observational data are required for validating satellite measurements and surface models which are used to investigate the forest-tundra ecotone. This data collection presents such data from two nearby sites in the forest-tundra ecotone in the Tasiapik valley near Umiujaq in northern Quebec, Canada. One site is on a mixture of lichen and low shrub tundra and the data set there comprises 9 years of meteorological, soil and snow data as well as 3 years of eddy covariance data. The other site, 850 m away, features vegetation consisting of black spruce, tall shrubs and grass. There, 6 years of meteorological, soil and snow data are available. In addition to the data from the automated stations, profiles of snow density and specific surface area were collected during winter field campaigns. This data set corrects and replaces Lackner, G et al. (2022): Hydrometeorological, snow and soil data from a low-Arctic valley in the forest-tundra ecotone in Northern Quebec. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.946538, and provides additional data on snow temperature and thermal conductivity.

Further funding: Natural Sciences and Engineering Research Council of Canada, Discovery grant program (https://www.nserc-crsng.gc.ca/professors-professeurs/grants-subs/dgigp-psigp_eng.asp) Northern Research supplement program (https://www.nserc-crsng.gc.ca/professors-professeurs/grants-subs/dgnrs-sdsrn_eng.asp)