This readme.txt file was generated on 2016-10-06 by Georgia Huang (DRUM Curator) ------------------- GENERAL INFORMATION ------------------- 1. Title of Dataset: Reconstruction of North American drainage basins and river discharge since the Last Glacial Maximum 2. Author Information Name: Wickert, Andrew D Institution: Department of Earth Science, University of Minnesota-Twin Cities Email: awickert@umn.edu 3. Date of data collection: 2011-11-01 to 2016-12-13 4. Geographic coverage of the data: North America 5. Information about funding sources that supported the collection of the data: Sponsorship: National Defense Science & Engineering Graduate Fellowship Program; National Science Foundation Graduate Research Fellowship under Grant No. DGE 1144083; Emmy Noether Programme of the Deutsche Forschungsgemeinschaft (DFG) through funds awarded to T. Schildgen under Grant No. SCHI 1241/1-1; Start-up funds from the University of Minnesota -------------------------- SHARING/ACCESS INFORMATION -------------------------- 1. Licenses/restrictions placed on the data: Attribution-ShareAlike 3.0 United States 2. Links to publications that cite or use the data: Wickert, A. D. Reconstruction of North American drainage basins and river discharge since the Last Glacial Maximum, Earth Surf. Dynam. Discuss. http://dx.doi.org/10.5194/esurf-2016-8 3. Was data derived from another source? Yes. The dataset is based on five ice-sheets and solid-Earth reconstructions. See citations below: ICE-3G: Tushingham, A. M., and W. R. Peltier (1991), Ice-3G: A new global model of Late Pleistocene deglaciation based upon geophysical predictions of post-glacial relative sea level change, J. Geophys. Res., 96(B3), 4497, doi:10.1029/90JB01583. ICE-5G: Peltier, W. R. R. R. (2004), Global Glacial Isostasy and the Surface of the Ice-Age Earth: The ICE-5G (VM2) Model and GRACE, Annu. Rev. Earth Planet. Sci., 32(1), 111–149, doi:10.1146/annurev.earth.32.082503.144359. ICE-6G: Argus, D. F., W. R. Peltier, R. Drummond, and A. W. Moore (2014), The Antarctica component of postglacial rebound model ICE-6G_C (VM5a) based on GPS positioning, exposure age dating of ice thicknesses, and relative sea level histories, Geophys. J. Int., 198(1), 537–563, doi:10.1093/gji/ggu140. Peltier, W. R., D. F. Argus, and R. Drummond (2015), Space geodesy constrains ice age terminal deglaciation: The global ICE-6G\_C (VM5a)model, J. Geophys. Res. Solid Earth, 120(1), 450–487, doi:10.1002/2014JB011176. ANU: Lambeck, K., Y. Yokoyama, and T. Purcell (2002), Into and out of the Last Glacial Maximum: sea-level change during Oxygen Isotope Stages 3 and 2, Quat. Sci. Rev., 21(1-3), 343–360. G12: Gregoire, L. J., A. J. Payne, and P. J. Valdes (2012), Deglacial rapid sea level rises caused by ice-sheet saddle collapses, Nature, 487(7406), 219–222, doi:10.1038/nature11257. 6. Recommended citation for the data: Wickert, Andrew D. (2016). Reconstruction of North American drainage basins and river discharge since the Last Glacial Maximum. Retrieved from the Data Repository for the University of Minnesota, http://doi.org/10.13020/D6D01H. --------------------- DATA & FILE OVERVIEW --------------------- 1. File List A. Filename: discharge_histories_2016.tar.gz Short description: Computed North American river discharge since the Last Glacial Maximum, stored in numpy binary files B. Filename: drainage_basin_histories_2016.tar.gz Short description: Computed North American drainage basins since the Last Glacial Maximum, stored in shapefiles C. Filename: NA_Figures_and_Movies_2016.tar.gz Short description: PNG images and movies of drainage basin, river (>1000 cubic meters per second), and ice-sheet evolution since the Last Glacial Maximum 2. Relationship between files: The drainage basins in the images are those from the shapefiles. The numpy binaries are the river discharges (roughly shown with the extent of the blue river channels in the images, which correspond to reaches with a discharge of at least 1,000 m^3/s. 3. Codes related to the data: Ice Age Rivers: a collection of codes and materials used to produce the images and videos https://github.com/awickert/ice-age-rivers North American Deglaciation: a static version of codes and outputs that accompany the paper "Reconstruction of North American drainage basins and river discharge since the Last Glacial Maximum" https://github.com/awickert/ice-age-rivers/releases/tag/v1.0 4. Are there multiple versions of the dataset? no -------------------------- METHODOLOGICAL INFORMATION -------------------------- 1. Description of methods used for collection/generation of data: Changes in major drainage basins and river discharges across North American since the Last Glacial Maximum from calculations based on five different reconstructions of past ice sheets and glacial-isostatic adjustment. River discharges are stored as Numpy binary files. Drainage basins are stored as shapefiles. Images and videos are available for each ice-sheet and glaical-isostatic adjustment model tested. These images show past topography and sea level, drainage basin extents as black lines, rivers with local flow greater than 1000 cubic meters per second as blue lines, and the footprint of the ice-sheet as a semitransparent light-colored region. Ages are in the folder and file names for the drainage basins and the images, and take the form, "0XXXXX', where this is the number of years before present (i.e. before 1950) that the rivers of North America are simulated to be structured as shown. 2. Instrument- or software-specific information needed to interpret the data: The numpy files and shapefiles were created using Python 2.7 within GRASS GIS 7.1. Software required to access the data are: any GIS software (QGIS, GRASS, ArcGIS) for the shapefiles, Python for the numpy files. ---------------------------------------------------------------- DATA-SPECIFIC INFORMATION FOR: [discharge_histories_2016.tar.gz] ---------------------------------------------------------------- 1. Included files: ANU.npy, G12.npy, ICE3G.npy, ICE5G.npy, ICE6G.npy (one numpy file for each ice-sheet). 2. keys of the dictionaries in the numpy files: [ages, ages_numeric]: ages (years before present) [Q_m]: discharge in each river system due to precipitation minus evapotranspiration (meteoric) [Q_i]: discharge in each river system due to ice melt [Q_t]: total discharge in each river system 3. Example code for loading the numpy files: a = np.load('ICE3G.npy').item() # if there is encoding error, use a = np.load('ICE3G.npy', encoding = 'latin1').item() a.keys() --------------------------------------------------------------------- DATA-SPECIFIC INFORMATION FOR: [drainage_basin_histories_2016.tar.gz] --------------------------------------------------------------------- 1. Included files: ANU, G12, ICE3G, ICE5G, ICE6G (one folder for each ice-sheet) ------------------------------------------------------------------ DATA-SPECIFIC INFORMATION FOR: [NA_Figures_and_Movies_2016.tar.gz] ------------------------------------------------------------------ 1. Included files: ANU.mov, G12.mov, ICE3G.mov, ICE5G.mov, ICE6G.mov (one movie for each ice-sheet). Corresponding png images used to make the movies. 2. Codes for producing the original images of the drainage basins: https://github.com/awickert/ice-age-rivers/blob/master/GRASSplot/Local_internal_functions/plot_topo_basins_alltimes_20160808.py 3. Codes for adding time-stamps and stitching together the movies (directory with both scripts):: https://github.com/awickert/ice-age-rivers/blob/master/GRASSplot/Local_internal_functions/plot_topo_basins_alltimes_20160808.py Credits: Template provided by the University of Minnesota Libraries, http://lib.umn.edu/datamanagement