2. Modeling evidence for recent warming of the Arctic soil thermal regime Christoph Oelke, Tingjun Zhang, and Mark Serreze coelke@nsidc.org October 27, 2003

3. Thermal Soil Model Finite difference, 1-D heat conduction with phase change (Goodrich, 1982) 3 major soil layers: 0 – 0.3 m, 0.3 – 0.8 m, 0.8 – 30 m 63 model nodes, resolution: 10 cm (near the surface) to 2 m (at 30 m depth) RIMS Arctic drainage area, 25 km x 25 km EASE Grid daily time step NCEP surface air temperature incl. topography correction snow depth from SMMR and SSM/I SWE

4. 1 2 3 4

5. Region 1: surface temp. 1980–2002: 0.044 K/yr 1994–2002: 0.142 K/yr Region 1: 2-m temp. 1980–2002: 0.033 K/yr 1994–2002: 0.113 K/yr

6. Continuous permafrost: Soil surface temperature (a), 2-m temperature (b) for 4 seasons

7. Average temperature profiles, and trend profiles (1980-2002)

8. DJFMAM JJASON

9. 9 Oelke, Zhang, & Serreze: Modeling evidence for recent warming of the Arctic soil thermal regime Arctic Drainage Basin: ALD

10. 10 Oelke, Zhang, & Serreze: Modeling evidence for recent warming of the Arctic soil thermal regime ALD anomaly by river basin (cont. + disc. permafrost)

11. 11 Oelke, Zhang, & Serreze: Modeling evidence for recent warming of the Arctic soil thermal regime Publications Oelke, C., T. Zhang, M.C. Serreze, and R.L. Armstrong, Regional-scale modeling of soil freeze/thaw over the Arctic drainage basin, J. Geophys. Res., 108 (D10), 4314, doi: 10.1029/2002JD002722, 2003. Oelke, C., and T. Zhang, Comparing thaw depths measured at CALM field sites to estimates from a medium-resolution hemispheric heat conduction model, 8 th Intl. Conf. on Permafrost, Extended Abstracts, 2003. Oelke, C., and T. Zhang, A model study of circum-Arctic soil temperatures, Permafrost and Periglacial Processes, submitted June 2003. Oelke, C., T. Zhang, and M.C. Serreze, An Arctic active-layer climatology, 1980–2002, in prep.

12. Modeling evidence for recent warming of the Arctic soil thermal regime Christoph Oelke, Tingjun Zhang, and Mark Serreze coelke@nsidc.org October 27, 2003