The Arctic is warming more than twice as fast as the rest of the world, with dramatically decreasing trends in sea-ice and snow cover. Arctic amplification of global warming is a feature of human-made climate change, but its causes and consequences are not fully understood. Arctic amplification results from a complex interplay of remote forcing and feedbacks, enhanced or dampened by a range of local feedbacks and forcing processes. Examples of feedback processes include melting of sea-ice and exposure of open waters, which absorbs more sunlight amplifying the warming. Other drivers of the warming amplification include changes in water vapor, clouds, heat transport and the vertical temperature structure.
Declining sulfate emissions in Europe over the last decades may have enhanced Arctic warming. However, model validations have revealed significant discrepancies between measured and modeled sulphate and other aerosols in the Arctic. In this project, we will use models to identify parameters that are particularly important for correctly simulating Arctic aerosols. Observational advances, such as long-term ground-based measurements, and an increasing number of field campaigns and cloud remote sensing products, will allow for a better evaluation of model performance.
In addition to aerosols, energy is also transported into the Arctic from lower latitudes. This also brings water vapor into the Arctic, which influences local feedbacks by enhancing the greenhouse effect directly, and indirectly by influencing cloud formation.
How clouds change with global warming is one of the largest remaining uncertainties in the climate response to human-made emissions. In this project we will investigate how the representation of aerosols in models impact clouds. We will also examine why models underestimate the liquid fraction in the clouds, and how this influences the level of Arctic warming.
The goal of the project is to bridge knowledge gaps related to drivers of arctic amplification by focusing on Arctic clouds, aerosols, and energy transport through state-of-the-art aerosol modelling and updated observations in the Arctic.
The Arctic is warming more than twice as fast as the rest of the world, with dramatically decreasing trends in sea-ice and snow cover (AMAP,2017). This ‘Arctic amplification’ of global warming is a feature of human-made climate change, but its causes and consequences are not fully understood. Predictive capability of Arctic climate change is crucial, but it is hampered by our limited understanding of key processes in the climate system. Major progress is needed in climate modeling to improve our ability to estimate changes in the Arctic in the future, and to provide a better scientific underpinning for policy decisions.
The goal of ACCEPT is to bridge knowledge gaps related to cloud feedbacks and Arctic aerosol and energy transport by linking state-of-the-art aerosol modelling with updated observations in the Arctic. Observational advances, such as long-term ground-based measurements, and an increasing number of field campaigns and cloud remote sensing products, allow for a more thorough and comprehensive evaluation of model performance – both when it comes to representation of Arctic aerosols and transport, and to important cloud processes.