Our Research
The Arctic is changing faster than any other location on Earth. These changes are unprecedented, and constitute a clear regime change. In contrast, signals have been slower to emerge in the Antarctic, but the longer-term changes and their consequences may be even more severe. High-latitude Earth system (HLES) changes directly affect indigenous communities and ecosystems, but also have global implications, for instance through sea level rise, and the impact of Arctic sea ice decline on mid-latitude weather. Other consequences may be economic (e.g. shipping), or related to energy security (e.g. natural resource exploitation) and national security (e.g. search and rescue, territorial disputes). Research on prediction and predictability of HLES variability and trends on seasonal to multi-decadal time scales is hence of significant societal importance.
The High-Latitude Application and Testing of Earth System Models (HiLAT) Science Focus Area is teaming up with the Regional Arctic System Model (RASM) project to improve our ability to predict the evolution of the polar Earth systems, and to anticipate on its global consequences. Our project is organized along 4 themes, each consisting of 2 topics. These tasks are addressed by flexible and overlapping task teams that assure integration across themes and project partners. At the heart of our project are two overarching principles that integrate our themes and topics into a coherent and comprehensive research plan:
Principle 1: Understanding exchange processes that link high- and lower latitude Earth systems, and the high-latitude feedbacks that modulate these exchanges. This principle recognizes the fact that the HLESs are intrinsically connected to the lower latitude Earth systems through the exchange of heat, water, and other climatologically active agents (like aerosols and nutrients). These exchanges are important drivers of HLES changes, but also shape the low-latitude responses to HLES change.
Principle 2: Validating and improving the representation of these processes in a hierarchy of models to evaluate the importance of these processes for HLES predictability. This principle motivates our approach of studying HLES processes in a hierarchy of models, ranging from reduced-order models that capture only the most fundamental processes, to DOE’s cutting edge high-resolution global and regional Earth system models. These models include the Regional Arctic System model (RASM); the Energy Exascale Earth System Model (E3SM) and its Arctic regionally refined configurations (E3SM-Arctic); and the CMIP6 archive of global climate model simulations.
The High-Latitude Application and Testing of Earth System Models (HiLAT) Science Focus Area is teaming up with the Regional Arctic System Model (RASM) project to improve our ability to predict the evolution of the polar Earth systems, and to anticipate on its global consequences. Our project is organized along 4 themes, each consisting of 2 topics. These tasks are addressed by flexible and overlapping task teams that assure integration across themes and project partners. At the heart of our project are two overarching principles that integrate our themes and topics into a coherent and comprehensive research plan:
Principle 1: Understanding exchange processes that link high- and lower latitude Earth systems, and the high-latitude feedbacks that modulate these exchanges. This principle recognizes the fact that the HLESs are intrinsically connected to the lower latitude Earth systems through the exchange of heat, water, and other climatologically active agents (like aerosols and nutrients). These exchanges are important drivers of HLES changes, but also shape the low-latitude responses to HLES change.
Principle 2: Validating and improving the representation of these processes in a hierarchy of models to evaluate the importance of these processes for HLES predictability. This principle motivates our approach of studying HLES processes in a hierarchy of models, ranging from reduced-order models that capture only the most fundamental processes, to DOE’s cutting edge high-resolution global and regional Earth system models. These models include the Regional Arctic System model (RASM); the Energy Exascale Earth System Model (E3SM) and its Arctic regionally refined configurations (E3SM-Arctic); and the CMIP6 archive of global climate model simulations.
Theme 1: The role of sea ice in mediating meridional heat transports in the ocean and atmosphere
Theme 1 puts high-latitude change in a global framework by exploring how high-latitude feedbacks influence the relative (ocean/atmosphere) partitioning of meridional exchanges of energy between high and lower latitudes. Topic 1.1 explores the role that Arctic sea ice plays in modulating the exchanges between the atmosphere and ocean, amplifying those signals through regional feedbacks, and subsequently modifying global meridional heat transports. Topic 1.2 assesses heat transport and sea ice connections in the southern hemisphere, and explores implications for the global energy balance.
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(a) Satellite data and (b) simulated sea ice concentration during the month of October (observation year 2017 and model year 33, respectively) over the Southern Ocean. The shaded dark blue region is the MRP. Polynyas are important conduits for air/sea heat and vapor exchange (Kurtakoti et al., 2018).
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Lake cover analysis of the Mackenzie river delta. The morphology of deltas determines its buffering capacity (Piliouras & Rowland, 2019).
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Theme 2: Role of fine-scale and transboundary transport processes in Arctic change
Theme 2 puts more attention on specific processes that have often been neglected in assessing drivers of high-latitude climate change: Topic 2.1 investigates the importance of fine-scale filamentary features, as we hypothesize that these fine-scale features are important in driving high-latitude change, with connections to the transport of warm air northward and cold air southward. Topic 2.2 explores the impact of riverine fluxes on the radiative balance of the Arctic ocean/sea ice system, as we hypothesize that changes in Arctic riverine fluxes (heat, freshwater nutrients, sediments, and CDOM) modulate Arctic warming and sea ice retreat through positive/negative feedbacks to the surface radiation budget.
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Theme 3: Extra-polar impacts of Arctic change
Theme 3 centers on the global consequences of Arctic change. Topic 3.1 applies a suite of analytical tools that have not previously been used at high latitudes to unravel teleconnections between Arctic change and mid-latitude systems. Topic 3.2 focuses on drivers of variability of the Arctic Ocean and sea ice circulation, their implications for the Arctic freshwater budget, and impacts on Atlantic Meridional Overturning Circulation (AMOC) and global climate.
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Grid structure of the E3SM-Arctic-OSI, the Arctic regionally-refined configuration of E3SM. The HiLAT-RASM team is using this ocean/sea ice model to explore Arctic freshwater pathways, and their impacts on the global ocean circulation.
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Theme 4: Decadal predictability of high-latitude environmental change
Theme 4 makes use of the knowledge gleaned within the other themes to explore the predictability of high-latitude change. Topic 4.1 implements and tests a new approach to merge models and observations into a combined dynamical and statistical (reduced, Bayesian) modeling framework. Topic 4.2 tests whether explicitly resolving fine-scale processes in the Arctic combined with internally consistent and realistic initial conditions can improve the predictability of the Arctic environment, and, if so, over what time scales.
