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UP: Fachverband Umweltphysik

UP 1: Oceanography and Climate Modelling

UP 1.5: Vortrag

Donnerstag, 2. September 2021, 12:00–12:15, H3

Arctic amplification: The role of moisture — •Felix Pithan — Alfred Wegener institute, Helmholtz Centre for Polar and Marine research, Bremerhaven

Global climate change is amplified in the Arctic mostly because of the surface albedo feedback and the stable stratification of the Arctic (wintertime) lower troposphere trapping most warming near the surface. While the water vapour feedback is much stronger at low than high latitudes, moist processes do have important implications for Arctic climate and climate change which will be discussed in this presentation. Much of the wintertime transport of moisture into the Arctic occurs in discrete intrusion events that substantially alter atmospheric profiles and the surface energy budget. Weather and climate models struggle to represent the air-mass transformations associated with such intrusions, causing important biases in temperature structures and surface fluxes. In a warmer climate, the amount of latent heat convergence in the Arctic increases at the expense of dry energy convergence. The corresponding increase in precipitation is substantially stronger than in the global mean, even when normalized by the regional warming. Improving the understanding and model representation of moist processes in the Arctic is necessary to better constrain projections of future Arctic warming and the associated sea-level rise and sea-ice retreat.