Model Output From the 'Frost Index' Permafrost Model: Variations in Circumpolar Frozen Ground Conditions and Modeled Future Conditions Authors: F.E. Nelson, O.A. Anisimov, N.I. Shiklomanov Affiliation: Department of Geography, University of Delaware, 216 Pearson Hall, Newark, DE 19716 Final date of maps: November 2000 Funding: Arctic System Science (ARCSS) Land-Atmosphere-Ice Interactions (LAII), National Science Foundation Grant No. OPP-9896238. Metadata file date: 27 November 2000, revised 3 January 2002 Map Basics: 1) Projection: lat/long 2) Units: decimal degrees 3) Resolution: 0.5 degree latitude, 1 degree longitude 4) Raster parameters: 279 rows by 360 columns 5) upper left corner: x = -180.0 y= 83.5 lower right corner: x = 179.0 y= -56.0 EXPLANATION OF MAPS Several environmental maps were constructed using results from the "frost index" permafrost model (Nelson and Outcalt, 1987) driven by modern climatic data and scenarios of climate change derived from three transient general circulation models (GCM) (Greco et al., 1994). The maps show the distribution of permafrost in the Northern Hemisphere under modern climatic conditions and GCM projections for 2050; relative changes in the depth of seasonal thawing projected for 2050; and a hazard index used as a metric to evaluate potential environmental hazards associated with thaw settlement and thermokarst. Maps are available as .jpg files. MAPS OF PERMAFROST DISTRIBUTION These maps were computed using: the frost-index-based permafrost model; global gridded air temperature and precipitation data; and climatic projections for 2050 derived from the transient GFDL, ECHAM1-A, and UKTR models. Computational details can be found in Anisimov and Nelson (1996, 1997). The three categories on the maps correspond to areas of continuous, discontinuous, and sporadic permafrost. Predicted areas in the three permafrost zones, obtained from the three climate models areas, are shown in Table 1. Table 1. Predicted for 2050 areas of the permafrost distribution in the Northern Hemisphere, (figures given in millions of square km) Climate scenario Total Continuous Discontinuous Sporadic Modern 27.22 (100%) 12.43 (100%) 6.05 (100%) 8.74 (100%) GFDL89 23.36 (86%) 10.00 (80%) 5.11 (84%) 8.25 (94%) ECHAM1-A 24.57 (90%) 10.92 (88%) 5.74 (95%) 7.90 (90%) UKTR 22.75 (84%) 9.28 (75%) 5.42 (90%) 8.05 (92%) ACTIVE-LAYER THICKNESS MAPS These maps were computed using the Kudryavtsev solution for depth of thaw, the FAO soil texture map (Staub and Rosenzweig, 1987), the IPA map of permafrost and ground ice conditions (Brown et al., 1997, modern temperature and precipitation data from the Global Ecosystem's data base (Leemans and Cramer, 1991), and projections of the 2050 climate derived from three transient GCMs (Greco et al., 1994). Computational details are provided in Anisimov et al. (1997). Maps presented here indicate the expected relative changes of the active layer thickness (% from modern) under the projected 2050 climate. HAZARD-POTENTIAL MAPS A semi-quantitative "hazard index" (Is) was used to classify permafrost with respect to its potential for development of destructive cryogenic processes under conditions of global warming. This index is given by: Is = DZal *Vi where DZal is the predicted relative change in active-layer thickness (Anisimov et al., 1997) and Vi is the volumetric proportion of the upper permafrost occupied by ground ice (Brown et al, 1997). The maps show hazard zonation for the GFDL, UKTR, and ECHAM1-A transient projection of the 2050 climate. Hazard potential is partitioned geographically into areas of "stable" permafrost, and "low," "moderate," and "high" susceptibility to thaw-induced destructive processes. Zones were delineated by partitioning the pooled frequency distributions of positive Is values obtained from the three GCMs, using a nested-means procedure (Scripter, 1970). After logarithmic transformation of raw values and application of the classing procedure, the two lowermost classes were combined to provide a conservative estimate of hazard potential in the Northern Hemisphere. DATA FILES The original output of the model, which was used to construct the maps of the permafrost distribution, changes in the active layer thickness, and environmental hazard index, is stored in ASCII text format in the files listed with the map categories and context below: Permafrost distribution data: Map categories: 0 - background 6 - continuous 7 - discontinuous 1 - sporadic Data file content: fr00.txt - modern climate fret.txt - ECHAM1-A projection for 2050 frgt.txt - GFDL89 projection for 2050 frut.txt - UKTR projection for 2050 Changes in permafrost zonation (note: minor corrections were made to the dfgt.txt and dfut.txt files on 3 January 2002): Map categories: 0 - background 1 - no change 2 - continuous to discontinuous transition 3 - discontinuous to sporadic transition 4 - thawing sporadic Data file content: dfet.txt - ECHAM1-A projection for 2050 dfgt.txt - GFDL89 projection for 2050 dfut.txt- UKTR projection for 2050 Permafrost hazard index: Map categories: 0 - background 1 - stable 2 - low 3 - moderate 4 - high hzet.txt- ECHAM1-A projection for 2050 hzgt.txt- GFDL89 projection for 2050 hzut.txt- UKTR projection for 2050 Relative changes of active layer thickness: Map categories: Relative change in percents raet.txt- ECHAM1-A projection for 2050 ragt.txt- GFDL89 projection for 2050 raut.txt- UKTR projection for 2050 FILE STRUCTURE (for each text file): north: 83:30:00N south: 56:00:00S east: 180:00:00E west: 180:00:00W cols: 360 rows: 279 0 0 0 0 0 0 0 0 0 ... data values. The northernmost row is at the top. Images are available in JPG format. References: Anisimov, O. A. and Nelson, F. E., 1996: Permafrost distribution in the northern hemisphere under scenarios of climatic change. Global and Planetary Change, 14: 59-72. Anisimov, O. A. and Nelson, F. E., 1997: Permafrost zonation and climate change: results from transient general circulation models. Climatic Change, 35: 241-258. Anisimov O.A., and Poljakov V.Yu., 1999: Forecasting air temperature for the first quarter of the XXI century, Meteorology and Hydrology, 1999/2:. 25-31 (in Russian). Anisimov, O.A. and Poljakov, V.Yu., 2000: Computerised geocryological information system for the studies of climate-permafrost interaction in the Northern Hemisphere. Published in: Proceedings of the American Geophysical Union, fall meeting, San-Francisco, 8-12 December 2000. Anisimov, O. A., Shiklomanov, N. I., and Nelson, F. E., 1997: Effects of global warming on permafrost and active-layer thickness: results from transient general circulation models. Global and Planetary Change, 15: 61-77. Brown, J., Ferrians, O. J. J., Heginbottom, J. A., and Melnikov, E. S., 1997: International Permafrost Association Circum-Arctic Map of Permafrost and Ground Ice Conditions. U.S. Geological Survey, Circum-Pacific Map Series, Map CP-45. Scale 1:10,000,000. Greco, S., Moss, R. H., Viner, D., Jenne, R., and Intergovernmental Panel on Climate Change, W. G. II., 1994: Climate Scenarios and Socioeconomic Projections for IPCC WG II Assessment. Washington, D.C.: Consortium for International Earth Science Information Network. 12 + maps, appendices, diskettes. Leemans, R. and Cramer, W., 1991: The IIASA Database for Mean Monthly Values of Temperature, Precipitation, and Cloudiness on a Global Terrestrial Grid. Research Report RR-91-18, International Institute for Applied Systems Analysis, Laxenburg, Austria, 62 pp. Nelson, F.E., Anisimov, O.A., and Shiklomanov, N.I., 2001: Climate change and hazard zonation in the circum-Arctic permafrost regions. Natural Hazards, in press. Nelson, F.E., Anisimov, O.A., and Shiklomanov, N.I., 2001: Subsidence risk from thawing permafrost. Nature 410: 889-890. Nelson, F. E. and Outcalt, S. I., 1987: A computational method for prediction and regionalization of permafrost. Arctic and Alpine Research, 19: 279-288. Scripter, M. W., 1970: Nested means map classes for statistical maps. Annals of the Association of American Geographers 60: 385-393. Staub, B. and Rosenzweig, C., 1987: Global Gridded Data Sets of Soil Type, Soil Texture, Surface Slope and Other Properties. Boulder, CO: National Center for Atmospheric Research. (http://www.ngdc.noaa.gov/seg/eco/cdroms/gedii_a/datasets/a11/sr.htm)