Arctic is entering into a new era where there is more open ocean in summer and increasing area of newly-formed sea ice in winter. Meanwhile, the new Arctic is undergoing a deep warming extending from the interior ocean to the upper troposphere. It implies significant changes of ocean conditions, atmosphere circulations and climate patterns, bringing challenges to the implementation of existing knowledge on the prediction of new Arctic climate system.

MAPARC aims to enhance the mechanistic understanding of Arctic climate change and improve the prediction of new Arctic climate system. We will quantify the observed changes of Arctic air-sea-ice interaction due to the increased area of newly-formed sea ice, and use state-of-the-art coupled climate model and regional atmospheric model to confirm the underlying thermodynamic feedbacks. Existing multi-model large ensemble climate simulations will be used to identify the local and remote processes responsible for the Arctic near-surface warming and deep warming and their downstream effects (e.g., extremes over Eurasia). We will then use the Norwegian Earth System Model and modern techniques such as causal effect networks to confirm the causality of climate linkages. We will further use the large ensemble simulations to assess the effects of externally-forced (e.g., radiative forcing), boundary forcing (e.g., sea ice and ocean temperature) and internal stochastic forcing on the changes of mid-high latitude atmospheric circulations such as stratospheric polar vortex, jet stream and blocking. Equipped with enhanced mechanistic understanding, we will then use the dynamical climate prediction systems and advanced approaches including statistical downscaling and machine learning to develop hybrid models for the prediction of new Arctic climate system. The well-established collaboration between the Norwegian and Chinese PIs and the complementary expertise and technology of the project group will ensure the success of MAPARC.