Deep sea observations explain biases in global climate models
The lack of observational data limits the possibility to fully grasp the role that deep Arctic Ocean waters play in the global climate. By analyzing new observational data of small, transient features of the Arctic Ocean, as well as historical time series, a new PhD thesis explains biases in global climate models.
– When discussing climate change it is important to realize that the changes we observe and feel as humans are a very small part of what is occurring. Most of the changes are instead occurring in the wide and deep expanse of the oceans, which covers most of the planet, Salar Karam says, new Doctor of Philosophy in Natural Sciences, University of Gothenburg.
His thesis explores a relatively unknown part of the Arctic climate system: the deep ocean.
The result show that biases found in global climate models are due to inadequate interaction between sea ice and the ocean, missing processes in the Arctic Ocean, as well as inaccuracies introduced from the Nordic Seas. From observational data gathered during the MOSAiC expedition, the importance of small-scale sea ice-ocean processes emerge.
Results from a historical Polar expedition
In his PhD thesis, Salar Karam focuses on the Eurasian Arctic. Parts of his observations and data collecting were carried out during the largest polar expedition in history, the MOSAiC expedition. He was one of hundreds of experts from 20 countries who boarded the German research icebreaker Polarstern in 2020, to take a closer look at the Arctic and gain insights about global climate change. This under challenging and unexpected circumstances due to the pandemic Covid19.
In addition, the study identifies new circulation pathways, and reveals that eddies have a significant impact on shaping deep ocean properties over extensive regions.
Another result of Salar Karam’s studies is that the deep waters of the Greenland Sea now act as a heat source for the central Arctic Ocean. This change is due to a significant warming trend resulting from the cessation of deep convection since the 1980s.
– The biases found in the climate models, and the importance these processes were found to have in observations, underscore the need to better incorporate these small-scale processes into future global climate models, Salar Karam says.
The research conducted as part of his thesis was funded by The Swedish Research Council Starting Grant.
Download the thesis “High-resolution dynamics of the deep Arctic Ocean: From thin meltwater layers to large-scale transport” from GUPEA: https://hdl.handle.net/2077/80886
For more information about the thesis, please contact:
Salar Karam, Doctor of Philosophy, Department of Earth Sciences, University of Gothenburg: salar.karam@gu.se
Deep seas are the parts of the world's oceans that are so far below the surface that little or no sunlight reaches them. In principle, the deep sea starts at a depth of around 300 meters, but the term is more often used to refer to depths greater than 2 000 meters, also known as the abyssal region. About 60% of the Earth's surface and 90% of the oceans are deep seas.
Source: Wikipedia
