Preprints
https://doi.org/10.5194/tc-2021-388
https://doi.org/10.5194/tc-2021-388
 
14 Jan 2022
14 Jan 2022
Status: a revised version of this preprint is currently under review for the journal TC.

The impact of climate oscillations on the surface energy budget over the Greenland Ice Sheet in a changing climate

Tiago Silva1, Jakob Abermann1,3, Brice Noël2, Sonika Shahi1, Willem Jan van de Berg2, and Wolfgang Schöner1,3 Tiago Silva et al.
  • 1Institute of Geography and Regional Science, Graz University, Austria
  • 2Institute for Marine and Atmospheric Research, Utrecht University, Netherlands
  • 3Austrian Polar Research Institute, Vienna, Austria

Abstract. Climate change is particularly strong in Greenland primarily as a result of changes in advection of heat and moisture fluxes from lower latitudes. The atmospheric structures involved influence the surface mass balance and their pattern are largely explained by climate oscillations which describe the internal climate variability. Based on a clustering method, we combine the Greenland Blocking Index and the North Atlantic Oscillation index with the vertically integrated water vapor to analyze inter-seasonal and regional impacts of the North Atlantic influence on the surface energy components over the Greenland Ice Sheet. In comparison to the reference period (1959–1990), the atmosphere has become warmer and moister during recent decades (1991–2020) for contrasting atmospheric circulation patterns. Particularly in the northern regions, increases in tropospheric water vapor enhance incoming longwave radiation and thus contribute to surface warming. Surface warming is most evident in winter, although its magnitude and spatial extent depend on the prevailing atmospheric configuration. Relative to the reference period, increases in sensible heat flux in the summer ablation zone are found irrespective of the atmospheric circulation pattern. Especially in the northern ablation zone, these are explained by the stronger katabatic winds which are partly driven by the larger surface pressure gradients between the ice/snow-covered surface and adjacent seas, and by the larger temperature gradient between near-surface air and the air above. Increases in net shortwave radiation are mainly connected to high-pressure systems. Whereas in the southern part of Greenland the atmosphere has gotten optical thinner, thus allowing more incoming shortwave radiation to reach the surface, in the northern part the incoming shortwave radiation flux has changed little with respect to the reference period, but the surface albedo decreased due to the expansion of the bare ice area.

Tiago Silva et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on tc-2021-388', Anonymous Referee #1, 01 Feb 2022
    • AC1: 'Reply on RC1', Tiago Silva, 15 Apr 2022
  • RC2: 'Comment on tc-2021-388', Anonymous Referee #2, 01 Feb 2022
    • AC2: 'Reply on RC2', Tiago Silva, 15 Apr 2022
  • RC3: 'Comment on tc-2021-388', Anonymous Referee #3, 11 Feb 2022
    • AC3: 'Reply on RC3', Tiago Silva, 15 Apr 2022

Tiago Silva et al.

Tiago Silva et al.

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Short summary
In order to overcome internal climate variability, this study investigates spatio-temporal changes of atmospheric drivers within key atmospheric circulation patterns (ACP) over the Greenland Ice Sheet (GrIS). We present the extent of the recent tropospheric warming and increase in water vapor as dependent on season and on the prevailing ACP along with regional impacts of atmospheric drivers on the GrIS surface energy components.