Articles | Volume 11, issue 4
Research article
05 Jul 2017
Research article |  | 05 Jul 2017

Evaluation of Greenland near surface air temperature datasets

J. E. Jack Reeves Eyre and Xubin Zeng

Abstract. 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. Here extensive in situ SAT measurements ( ∼  1400 station-years) are used to assess monthly mean SAT from seven global reanalysis datasets, five gridded SAT analyses, one satellite retrieval and three dynamically downscaled reanalyses. Strengths and weaknesses of these products are identified, and their biases are found to vary by season and glaciological regime. MERRA2 reanalysis overall performs best with mean absolute error less than 2 °C in all months. Ice sheet-average annual mean SAT from different datasets are highly correlated in recent decades, but their 1901–2000 trends differ even in sign. 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.

Short summary
We have used extensive air temperature measurements (~  1400 station-years) to assess more than 10 gridded datasets over the Greenland ice sheet. We recommend the best datasets for estimating past melting of the ice sheet and show that choice of dataset is important for evaluating 31 earth system models. Most, but not all, of the datasets show similar history of temperature changes over the 20th century, and the earth system models generally capture long-term warming but not decadal variations.