Abstract
Abstract. CMIP5, CMIP6, and ERA5 Antarctic precipitation is evaluated against CloudSat data. At continental and regional scales, ERA5 and the median CMIP models are biased high, with insignificant improvement from CMIP5 to CMIP6. However, there are fewer positive outliers in CMIP6. AMIP configurations perform better than the coupled ones, and, surprisingly, relative errors in areas of complex topography are higher (up to 50 %) in the five higher-resolution models. The seasonal cycle is reproduced well by the median of the CMIP models, but not by ERA5. Progress from CMIP5 to CMIP6 being limited, there is still room for improvement.
Highlights
Antarctica is the largest freshwater reservoir on Earth
Following Palerme et al (2017) who compared CMIP5 models to CloudSat snowfall measurements, we have identified CMIP5 and CMIP6 models that have continent-wide mean snowfall rates within 20 % of the CloudSat average value of 186 mm w.e. yr−1, that is, between 150 and 223 mm yr−1
Substantial fraction of Coupled Model Intercomparison Project (CMIP) models, in both CMIP5 and CMIP6, exceed the upper bound of 223 mm yr−1
Summary
Because of its sea-level equivalent of 57.9 ± 0.9 m (Morlighem et al, 2019), even minor changes of the ice sheet mass balance can have important consequences for global sea level. Apart from a small contribution from ice deposition, precipitation is by far the dominant positive term in the ice sheet mass balance. At equilibrium it is compensated for by meltwater drainage and ice discharge (e.g., Favier et al, 2017). Precipitation is the main source of interannual mass balance variability of the ice sheet (e.g., Boening et al, 2012) and is projected to increase in a warmer future (e.g., Frieler et al, 2015). An evaluation of the most recent CMIP6 (World Climate Research Programme (WCRP) Coupled Model Intercomparison Project Phase 6) coordinated climate model simulations (Eyring et al, 2016) is timely
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