Which Burners Heat the Arctic Atmosphere?
Abstract
Several lines of observational and modelling evidence show that Arctic amplification (AA) caused by greenhouse warming extends from the Arctic surface into the Arctic free troposphere. Understanding the dynamical origin of free Arctic tropospheric warming helps constrain changes to the Arctic lapse rate feedback and its control on climate sensitivity. A wide range of theories and mechanisms have been proposed to explain the warming of the free Arctic troposphere. Simplified and comprehensive climate model experiments, as well as observational analysis, suggest that midlatitude surface heating anomalies can be communicated to the Arctic free troposphere via large-scale transport of air masses along moist isentropic surfaces. This analysis is complemented by a novel diagnostic of the diabatic origin of Arctic midtropospheric heat content, which quantifies the sensitivity of Arctic air masses to midlatitude large-scale condensation and tropical deep convection. Taken together, we are learning how the Arctic atmosphere and its sensitivity to global warming is highly dependent on processes occuring far outside the Arctic atmosphere.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A34E..01K
- Keywords:
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- 3305 Climate change and variability;
- ATMOSPHERIC PROCESSESDE: 3319 General circulation;
- ATMOSPHERIC PROCESSESDE: 3337 Global climate models;
- ATMOSPHERIC PROCESSESDE: 4313 Extreme events;
- NATURAL HAZARDS