Randolph Glacier Inventory (RGI 6.0)

The Randolph Glacier Inventory (RGI) is a globally complete inventory of glacier outlines. It is supplemental to the database compiled by the Global Land Ice Measurements from Space initiative (GLIMS). While GLIMS is a multi-temporal database with an extensive set of attributes, the RGI is intended to be a snapshot of the world’s glaciers as they were near the beginning of the 21st century (although in fact its range of dates is still substantial). Production of the RGI was motivated by the preparation of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5). Version 1.0 of the RGI was released in February 2012. It included a considerable number of unsubdivided ice bodies, which we refer to as glacier complexes, and a considerable number of nominal glaciers, which are glaciers for which only a location and an area are known; they are represented by circles of the appropriate area at the given location. Version 6.0, released in July 2017, has improved coverage of the conterminous US (regions 02-05 and 02-06), Scandinavia (region 08) and Iran (region 12-2). In Scandinavia several hundred smaller glaciers have been added and most glaciers now have exact dates. The flag attributes RGIFlag and GlacType were reorganized. Surging codes have been added from Sevestre and Benn (2015). For version 1.0, we visualized the data in a geographic information system by overlaying outlines on modern satellite imagery, and assessed their quality relative to other available products. In several regions the outlines already in GLIMS were used for the RGI. Data from the World Glacier Inventory (WGI, http://nsidc.org/data/docs/noaa/g01130_glacier_inventory/ ; WGI, 1989) and the related WGI-XF ( http://people.trentu.ca/~gcogley/glaciology ; Cogley, 2009) were used for some nominal glaciers, mainly in the Pyrenees and in northern Asia. Where no other data were available we relied on data from the Digital Chart of the World (Danko, 1992). The RGI is provided as shapefiles containing the outlines of glaciers in geographic coordinates (longitude and latitude, in degrees) which are referenced to the WGS84 datum. Data are organized by first-order region. For each region there is one shapefile (.SHP with accompanying .DBF, .PRJ and .SHX files) containing all glaciers and one ancillary .CSV file containing all hypsometric data. The attribute (.DBF) and hypsometric files contain one record per glacier. Each object in the RGI conforms to the data-model conventions of ESRI ArcGIS shapefiles. That is, each object consists of an outline encompassing the glacier, followed immediately by outlines representing all of its nunataks (ice-free areas enclosed by the glacier). In each object successive vertices are ordered such that glacier ice is on the right. This data model is not the same as the current GLIMS data model, in which nunataks are independent objects. The outlines of the RGI regions are provided as two shapefiles, one for first-order and one for second-order regions. A summary file containing glacier counts, glacierized area and a hypsometric list for each first-order and each second-order region is also provided. The 0.5°×0.5° grid is provided as a plain-text .DAT file in which zonal records of blank-separated glacierized areas in km2 are ordered from north to south. Information about RGI glaciers that are present in the mass balance tables of the WGMS database Fluctuations of Glaciers is provided as an ancillary .CSV file. The 19 regional attribute (.DBF) files are also provided in .CSV format. References RGI Consortium, 2017, Randolph Glacier Inventory (RGI) – A Dataset of Global Glacier Outlines: Version 6.0. Technical Report, Global Land Ice Measurements from Space, Boulder, Colorado, USA. Digital Media. DOI: https://doi.org/10.7265/N5-RGI-60 Pfeffer, W. T., Arendt, A. A., Bliss, A., Bolch, T., Cogley, J. G., Gardner, A. S., Hagen, J-O., Hock, R., Kaser, G., Kienholz, C., Miles, E. S., Moholdt, G., Molg, N., Paul, F., Radic, V., Rastner, P., Raup, B. H., Rich, J., Sharp, M. J. Glasser, N. (2014). The Randolph Glacier Inventory: A globally complete inventory of glaciers. Journal of Glaciology, 60 (221), 537-552. https://www.cambridge.org/core/services/aop-cambridge-core/content/view/730D4CC76E0E3EC1832FA3F4D90691CE/S002214300020600Xa.pdf/randolph_glacier_inventory_a_globally_complete_inventory_of_glaciers.pdf