AGU: Geophysical Research Letters

 

Editors' Highlight

Twentieth-century Antarctic air temperature and snowfall simulations: Comparing observations and climate models

Establishing multidecadal, continental-scale records of near-surface air temperature (NSAT) and snowfall accumulation in Antarctica is important for understanding regional climate variability and the role Antarctic ice sheets play in global sea level change. Although generating such records is challenging due to Antarctica's sparse observational network, several recent studies have enhanced the observational data on NSAT and snowfall primarily during the past 50 years. Monaghan et al. (2008) compared these enhanced data with global climate models (GCMs), particularly those that support the Intergovernmental Panel on Climate Change's (IPCC) Fourth Assessment Report. They found that annual Antarctic snowfall accumulation trends in GCMs agree with observations during 1960-1990, and the sensitivity of snowfall to NSAT fluctuations is similar to that observed. However, longer-term NSAT trends (spanning 1880-1999) in the GCMs are about 2.5-5 times larger than observed, possibly due to the radiative impact of unrealistic increases in water vapor. Until these issues are resolved, IPCC projections of 21st-century Antarctic temperatures and snowfall amounts should be treated with caution.

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