TIME SERIES OF ACTIVE LAYER THICKNESS IN THE RUSSIAN ARCTIC, 1930-1990 DATA ORGANIZATION The directory structure of the ZIP is outlined below: Data files are named following the convention TMD2.sss.max where sss is the three-digit station identification number. The supplementary composite file including the average active layer thickness of all 31 sites for each year is titled Composite_1930-1990_ALT.txt. The following files are also included in the directory: pf_station_locations.gif - This GIF file shows the distribution of the 31 ground-based stations where data was collected. Active_Layer_Station_List.xls - This Excel file includes a list of the 31 ground-based stations with their station ID, region ID, World Meteorological Organization ID, station name, latitude, longitude, and elevation (m). DOCUMENTATION Please be sure to read the complete documentation in detail before working with the data.