Jul 5, 2017

Evaluation of Greenland near surface air temperature datasets

by
Reeves Eyre, J. E. Jack, Zeng, Xubin
,
The Cryosphere
  • States that near-surface air temperature (SAT) over Greenland has important effects on mass balance of the ice sheet, but it is unclear which SAT datasets are reliable in the region
  • Uses extensive in situ SAT measurements ( ∼  1400 station-years) to assess monthly mean SAT from seven global reanalysis datasets, five gridded SAT analyses, one satellite retrieval and three dynamically downscaled reanalyses
  • Identifies strengths and weaknesses of these products and finds their biases vary by season and glaciological regime
  • Finds that MERRA2 reanalysis overall performs best with mean absolute error less than 2 °C in all months
  • Finds that ice sheet-average annual mean SAT from different datasets are highly correlated in recent decades, but their 1901–2000 trends differ even in sign
  • Results show that, compared with the MERRA2 climatology combined with gridded SAT analysis anomalies, thirty-one earth system model historical runs from the CMIP5 archive reach  ∼  5 °C for the 1901–2000 average bias and have opposite trends for a number of sub-periods