Understanding the predictability of the Arctic climate
The barren and inhospitable Arctic region has over recent decades seen large changes in its natural environment. Observations have shown that the Arctic is warming twice as fast compared to the rest of the world, mostly noticed by the strong decrease of sea ice. These changes present large threats t...
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| Other Authors: | , |
| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
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Wageningen University
2018
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| Online Access: | https://research.wur.nl/en/publications/understanding-the-predictability-of-the-arctic-climate https://doi.org/10.18174/456694 |
| Summary: | The barren and inhospitable Arctic region has over recent decades seen large changes in its natural environment. Observations have shown that the Arctic is warming twice as fast compared to the rest of the world, mostly noticed by the strong decrease of sea ice. These changes present large threats to the unique Arctic ecosystem and indigenous communities, but also provides opportunities such as improved navigation of the fabled northerly passages and exploration of natural resources. Hence, from a scientific, ecological and an economic viewpoint there is a strong need for accurate knowledge on future development of the Arctic climate, and specifically its sea ice cover. This thesis therefore focuses on the predictability of the Arctic climate on time scales ranging from seasonal to centennial, with an emphasis on the physical processes that give rise to, or inhibit, this predictability. This is achieved by studying the physical mechanisms related to Arctic climate variability and climate change, both in climate models and observations. Over recent years there has been an increase in using fully coupled climate models for seasonal to decadal predictions. Hence, it is important to understand the physical processes that provide predictability beyond persistence of sea ice anomalies in these climate models. In chapter 2 we analyze the natural variability of Arctic sea ice from an energy budget perspective in multiple climate models and compare these results to observations. The Arctic energy balance components primarily indicate the important role of the ice–albedo feedback, through which sea ice anomalies in the melt season reemerge in the growth season. The role of the ocean lies mainly in storing heat content anomalies in spring and releasing them in autumn. Confirming a previous (observational) study, we demonstrate that there is delayed atmospheric response of clouds in autumn to spring sea ice anomalies. Hence, there is no cloud–ice feedback in late spring and summer, but there is a cloud–ice feedback in ... |
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