--------------------------------------------------------------------------- This README file provides a brief description and format of the data sets --------------------------------------------------------------------------- These datasets describe annual historical changes (starting from 1770) in land cover and underlying land-use conversions at 0.5x0.5 degree resolution. The datasets are currently available in NETCDF format. Three distinct estimates of land-cover change and land-use conversions were reconstructed using three different datasets on cropland and pastureland. The three agricultural land-use datasets were based on 1. RF data (updated estimates based on Ramankutty and Foley, 1999) 2. HYDE data (HYDE 3.1 'baseline' scenario - Klein Goldewijk et al. 2011) 3. HH data (Houghton 2008 - estimates based on FAO 2006) All the three estimates used common wood harvesting and urban land data based on Hurtt et al. (2011) and Klein Goldewijk et al. (2010) respectively. The method of reconstruction utilized multiple years of MODIS land cover data (Friedl et al. 2010) as boundary conditions to implicitly account for unaccounted historical land-cover change. The land cover maps produced for recent years are consistent with MODIS satellite estimates. The three estimates developed based on three agricultural datasets (HYDE, RF and HH) are referred to as ISAM-HYDE, ISAM-RF and ISAM-HH respectively. ISAM-HYDE estimates cover the period 1770-2010. ISAM-RF estimates cover the period 1770-2007. ISAM-HH estimates cover the period 1770-2005. The annual land-cover maps contain the area (as percentage of grid cell area) of 28 land-cover types within each 0.5x0.5 degree grid cell. The 28 land-cover types are as follows: 1 Tropical Evergreen Broadleaf Forest 2 Tropical Deciduous Broadleaf Forest 3 Temperate Evergreen Broadleaf Forest 4 Temperate Evergreen Needleleaf Forest 5 Temperate Deciduous Broadleaf Forest 6 Boreal Evergreen Needleleaf Forest 7 Boreal Deciduous Needleleaf Forest 8 Savanna 9 C3 Grassland/Steppe 10 C4 Grassland/Steppe 11 Dense Shrubland 12 Open Shrubland 13 Tundra 14 Desert 15 Polar Desert/Rock/Ice 16 Secondary Tropical Evergreen Broadleaf Forest 17 Secondary Tropical Deciduous Broadleaf Forest 18 Secondary Temperate Evergreen Broadleaf Forest 19 Secondary Temperate Evergreen Needleleaf Forest 20 Secondary Temperate Deciduous Broadleaf Forest 21 Secondary Boreal Evergreen Needleleaf Forest 22 Secondary Boreal Deciduous Needleleaf Forest 23 Water/Rivers 24 C3 Cropland 25 C4 Cropland 26 C3 Pastureland 27 C4 Pastureland 28 Urban land The annual land-use conversion maps contain the area transitioned (as percentage of grid cell area) for each of the 92 unique conversions possible (Please refer supplementary Table S1 in the paper) for each 0.5x0.5 degree grid cell. Land-use conversions which are less than 0.001 % of the grid cell area have been screened out. Please note that certain variables stored in the NETCDF file use a 'scaling factor' for efficiency purposes. The annual land-cover datasets use a scaling factor of 0.01, and land-use conversion datasets use a scaling factor of 0.001. The values stored in the variable should be multiplied by 'scaling factor' to yield the actual values. Detailed information associated with each variable is included as attributes (metadata) in the NETCDF file. Reference Meiyappan, P., and Jain, A. K. (2012), Three distinct global estimates of historical land-cover change and land-use conversions for over 200 years, Frontiers of Earth Science, 6(2), 122-139. ------------------------------------ For any questions, contact: Prasanth Meiyappan University of Illinois at urbana-Champaign meiyapp2@illinois.edu ------------------------------------