Abstract | Accurate historical precipitation rates over the ice sheets are important for estimating ice sheet surface mass balance and for projecting future sea-level rise. Recent work shows that precipitation distributions from the European Centre for Medium-Range Weather Forecast’s Reanalysis (ERA5) are more similar to observations of accumulation derived from shallow ice cores than other commonly used Global Reanalyses products, such as CRUNCEP. However, the ERA5 data were not available to force stand-alone E3SM Land Model (ELM) simulations until now. Here we introduce the quarter degree ERA5 near-surface variables into ELM as two new data atmospheric forcing options, one is an hourly quarter-degree forcing dataset and the second is a 6-hourly quarter-degree forcing dataset, both available for 1979-2022. The 6-hourly product maintains the improved precipitation over ice sheets of the hourly data yet reduces the total model run time by about 2.5x. We have conducted a 300-year spin-up simulation using the 6-hourly quarter-degree ERA5 atmospheric forcing. This simulation exhibits an improved deep firn representation over the Greenland ice sheet and the outer perimeter of the Antarctic ice sheet and will provide an improved branching point for those interested in applying the ERA5 data atmosphere to historical simulations. It also allows for improved estimates of surface mass balance over the Greenland and Antarctic ice sheets. |
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