Characterizing the atmospheric boundary layer over Disko Bay: local structure and links to global dynamics

Characterizing the atmospheric boundary layer over Disko Bay: local structure and links to global dynamics

Project manager: Arno Hammann, researcher, Asiaq – Greenland Survey
Others involved: Kirsty Langley, researcher at Asiaq, and Kerstin Krøier Rasmussen, NuukBasic research assistant, Asiaq

Keywords: boundary layer, temperature inversion, cloud radiative effect, microwave radiometer, atmospheric rivers, moisture intrusions
Research area, purpose and research questions:
Our ability to predict the longer-term evolution of arctic climate as well as the weather on shorter timescales is currently limited in particular by a lack of detailed understanding of the processes occurring in the atmospheric boundary layer (ABL), the lowermost part of the atmosphere which interacts strongly with the earth’s surface. That surface air temperatures have increased almost twice as fast in the arctic than in the global average has to do with feedbacks occurring in the ABL, specifically those involving moisture. We propose to use a comprehensive multi-sensor observational dataset from the Greenland Ecosystem Monitoring (GEM, research site in Qeqertarsuaq in order to identify dominant structural and behavioral patterns of the ABL. They will be related to the large-scale atmospheric circulation via an analysis of the global ERA5 reanalysis dataset, with a focus on moisture transport from humid latitudes. The statistical analysis will comprise both process-level relationships between observed variables (regressions) for individual events and pattern recognition techniques (clustering) for the identification of dominant patterns on the small and large scale, an approach particularly suited for the study of an unsteady, changing climate.

Methods of inclusion of society:
A detailed scientific understanding of polar ABL processes is crucial to improving predictive capabilities both on short and long time scales, and thereby of great societal relevance to Greenland. Short-term weather prediction, in particular of fog and low clouds and associated precipitation, is of particular importance for aviation, but also for ship and boat traffic, water resources planning and infrastructure projects. Long-term climate predictions for the arctic are particularly uncertain due to a lack of understanding of ABL feedback processes, and the rate of surface
warming, sea ice retreat and snow cover changes are all underpredicted by current models. Apart from this relevance for model improvement, an improved knowledge of typical durations of cloudy states and precipitation rates, and of the interactions between the ABL and sea ice cover, are of direct interest to local decision makers in their own right.

Methods of dissemination to society:
The results of this study will be disseminated in popular scientific form in the GEM report cards, as a scientific report, and as a peer-reviewed scientific paper. We will also present the results at the Greenland Science Week 2022.

Project start and completion date: January 1, 2021 – September 30, 2022

Granted: 99.900,00 kr.

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