Key Processes to understand Arctic Climate Warming

WP7 preforms in-depth analysis of enhanced NorESM simulations of WP6 focusing on coupled feedbacks leading to potentially irreversible climate change. Key tasks include:

1. To quantify how enhanced lateral resolution in our ocean model improves the representation of mesoscale eddies and of climate at high northern latitudes. This work extends to the quantification of changes in deep water formation in regions of open sea convection and on the Arctic continental shelves.

WP5 's overarching objective is to quantify the changes in land and ocean biogeochemical cycles invoked by Arctic warming and compare these to future anthropogenic atmospheric composition change. Secondary objectives: (1) Implement in NorESM a consistent air-sea-exchange scheme for climate relevant gases and couple to an improved aerosol and gas-phase chemistry scheme; (2) Explore feedback processes involving these emissions and validate with current observational data sets.

Interactive emissions and improved atmospheric chemistry

WP4 aims to understand how feedbacks involving the coupled atmosphere, cryosphere and hydrosphere contribute to the accelerated rate of Arctic warming.

1. Ensure that NorESM reproduces Arctic cloud phase observations.

2. Achieve a realistic NorESM treatment of snow hydrology over sea ice.

3. Perform the first NorESM simulation with interactive land ice to study the mass balance of the Greenland ice sheet.

WP3 aims to improve representation of boundary layer processes in NorESM.

1. Explore effects on surface Arctic temperature and stratification associated with coupled ocean and atmosphere boundary-layer processes in the key region and improve their representation.

2. Explore effects of bottom topography and sea ice in the parameterisation of unresolved high latitude ocean eddy transport.

3. Identify and remove numerical modes in the dynamical ocean-sea ice coupling in NorESM.

This WP aim to analyse and quantify mechanisms contributing to changes in the hydrological cycle and energy balance of the key region.

1 Quantify atmospheric heat and moisture transport and oceanic heat transport and their effects on the sea ice, ocean salinity and precipitation in the key region

2. Quantify the hydrological response in the key region to large-scale atmospheric conditions.

In WP1 we aim to understand key physical processes for climate change and diversity in their
representation in multi-model climate simulations on a global scale and over the key region:

1. Quantify forcing in terms of effective radiative forcing, quantify climate feedbacks, and quantify circulation changes

2. Establish bias and deficiencies in NorESM in comparison to CMIP6 model ensemble.

This work package focuses on advancing our understanding of the response of the fully coupled Norwegian Earth system model (NorESM) to changes in process parameterizations. Changes will be made in individual model components and eventually combined allowing us to investigate the collective effect of the changes. The new knowledge will allow us to elucidate sources of uncertainties in NorESM projections as well as provide insights that feed directly into future model developments.