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Northern Hemisphere Land Snow Cover: Simulations vs. Reality

Reference
Brutel-Vuilmet, C., Menegoz, M. and Krinner, G. 2013. An analysis of present and future seasonal Northern Hemisphere land snow cover simulated by CMIP5 coupled climate models. The Cryosphere 7: 67-80.
Noting that "the fifth phase of the Coupled Model Intercomparison Project (CMIP5), linked to the preparation of the fifth IPCC assessment report, is currently ongoing [and] running with the most recent versions of more than 30 state-of-the-art coupled climate models and a new set of climate forcing scenarios," Brutel-Vuilmet et al. (2013) say "it is thus timely to address the following questions: how well do CMIP5 models capture present-day seasonal snow extent and observed recent trends?"

In pursuit of this goal, Brutel-Vuilmet et al. proceed to provide what they describe as "a short assessment of the simulated present-day snow cover, including its current trends," as well as an analysis of "the dominant factors determining the future evolution of Northern Hemisphere spring snow cover as simulated by the CMIP5 models." Among a number of disheartening findings, the three French researchers determined that "the significant trend towards a reduced spring snow cover extent over the 1979-2005 period is underestimated (simulated -1.0±0.3% per decade; observed -3.4±1.1% per decade)," and this finding, as they describe it, "is linked to the simulated Northern Hemisphere extra-tropical spring land warming trend over the same period, which is also underestimated. In addition, they note that the simulated linear relationship between the hemispheric seasonal spring snow cover extent and global mean annual surface air temperature is itself underestimated at present (simulated -5.1±3.0% per °C; observed -11.8±2.7% per °C).

In commenting further on their findings, Brutel-Vuilmet et al. write that "in many respects, the simulated snow covers in the coupled models used in CMIP3 as analyzed by Roesch (2006) and CMIP5 have similar qualities and deficiencies," leaving pause to wonder why so little progress has been made in so many different aspects of the climate-modeling enterprise.

Additional Reference
Roesch, A. 2006. Evaluation of surface albedo and snow cover in AR4 coupled climate models. Journal of Geophysical Research 111: 10.1029/2005JD006473.

Archived 31 July 2013