An RCM projection of soil thermal and moisture regimes for North American permafrost zones

Abstract

The fourth-generation Canadian Regional Climate Model (CRCM4) projected changes to the soil thermal and moisture regimes for the continuous, discontinuous, sporadic and isolated permafrost regions in North America, for the 2041-2070 period with respect to the 1961-1990 base period, for the SRES (Special Report on Emissions Scenarios) A2 scenario are presented. The projections indicate significant increase in the near-surface soil temperatures for all permafrost zones, with maximum warming for the continuous permafrost zone. No significant changes in the timing of minimum and maximum near-surface soil temperatures are projected by the CRCM4. However, the distributions of both minimum and maximum temperatures, at the surface and for the various near-surface soil layers, for the future climate, are significantly different from those for current climate. Intensification of the hydrologic cycle in future climate for the various permafrost zones is projected with important changes to the soil moisture regime, which are reflected in the reduction of the frozen soil moisture content, which in turn increases the deep drainage for all permafrost zones. Copyright 2007 by the American Geophysical Union.