EMULATE: Enhancing Mechanistic Understanding of mid-latitude LArge-scale circulaTion Errors
Improving understanding of circulation biases in climate models and linking these to downstream extreme events.
Objectives
1) Through a more detailed investigation of existing climate model archives build new storylines elucidating why some models do/do not reproduce critical features of the midlatitude circulation;
2) Develop a more nuanced understanding of the physical drivers of atmospheric circulation biases, the relative contributions of these drivers and their implications for other features of atmospheric variability;
3) Investigate the role that features in the tropics, and their representation, can play in driving or modulating midlatitude circulation biases;
4) Explore the impacts of circulation biases on the representation of extreme events, and said events sensitivity to large-scale biases, with a focus on the European sector;
5) Investigate links between circulation biases and regional ocean circulation and heat transport with a particular focus on the Nordic seas.
Project Summary
The projected response of the atmospheric circulation to radiative changes driven by increasing greenhouse gas concentrations is currently highly uncertain (Shepherd, 2014; Bony et al., 2015a; Ceppi and Shepherd, 2017). One of the primary reasons for this uncertainty is that the state-of-the- art models we employ to investigate these responses struggle to represent important features of the midlatitude circulation such as: storm tracks, jets and blocking. Though the scientific community has exhaustively diagnosed the existence of these biases and related model shortcomings our understanding of their drivers remains limited. The primary goal of EMULATE is to improve the physical understanding of these critical circulation features as well as the drivers and implications of their biases. The investigation will cover the entire Northern Hemisphere but special attention will be reserved for the critical North Atlantic/European sector. This is due to the project teams’ expertise as well as the region’s importance as a location where the implications of circulation biases have profound consequences.
