Jaclyn Clement Kinney

Recent Variability in Sea Ice Cover, Age, and Thickness in the Pacific Arctic Region

Over the past several decades, there has been a fundamental shift in sea ice cover, age, and thickness across the Pacific Arctic Region (PAR). Satellite data reveal that trends in sea ice cover have been spatially heterogeneous, with significant declines in the Chukchi Sea, slight declines in the Bering Strait region, yet increases in the northern Bering Sea south of St. Lawrence Island. Declines in the annual persistence of seasonal sea ice cover in the Chukchi Sea and Bering Strait region are due to both earlier sea ice breakup and later sea ice formation. However, increases in the persistence of seasonal sea ice cover south of St. Lawrence Island occur primarily owing to earlier sea ice formation during winter months. Satellite-based observations of sea ice age along with modeled sea ice thickness provide further insight into recent sea ice variability throughout the PAR, with widespread transitions towards younger, thinner ice. Investigation of sea ice cover, age, and thickness in concert provides critical insight into ongoing changes in the total volume of ice and therefore the future trajectory of sea ice throughout the PAR, as well as its likely impacts on ecosystem productivity across all trophic levels.

Toward Prediction of Environmental Arctic Change

Models help researchers understand past and present states as well as predict scenarios of environmental change in the Arctic. The authors analyze results on melting sea-ice from a regional coupled ice-ocean model and demonstrate their robustness independent of timescales for surface temperature and salinity relaxation.

Shelf-Break Exchange in the Bering, Chukchi and Beaufort Seas

The Bering and Chukchi/Beaufort shelf-breaks form the beginning and end of the dramatic sea-level and wind-forced flow of Pacific Ocean water across the Bering and Chukchi continental shelves between the Pacific and Arctic Oceans. Recent model results suggest that the on-shelf flow in the Bering is distributed along the shelf-break, wind-dependant, focused by Zhemchug and Bering canyons and modified by shelf-break eddies. Similarly, the off-shelf flow in the Chukchi/Beaufort is mediated by canyons, shelf-break jets, eddies, and wind forcing. In the Chukchi, flow is channeled through Barrow and Herald canyons to the shelf-break, where across-slope flow in Ekman boundary layers and instabilities result in the exchange of water and properties across the slope. In addition, dense shelf-water, created from brine rejection during ice formation in coastal polynyas, has been observed to flow downslope through Barrow Canyon. Along the Beaufort shelf, the shelf-break current is unstable, shedding eddies that populate the deep Beaufort basin. Upwelling favorable winds in summer have been observed to modify the structure of the shelf-break current and drive exchange across the Chukchi and Beaufort slopes. Most of our understanding of shelf-break flow in Bering and Chukchi Seas is based on numerical model results and broad-scale observations. There is thus a need for more detailed shelf-break observational programs.

On the Flow Through Bering Strait: A Synthesis of Model Results and Observations

Bering Strait is the only ocean connection between the Pacific and the Arctic. The flow through this narrow and shallow strait links the Pacific and Arctic oceans and impacts oceanic conditions downstream in the Chukchi Sea and the Western Arctic. We present a model synthesis of exchanges through Bering Strait at monthly to decadal time scales, including results from coupled ice-ocean models and observations. Significant quantities of heat and freshwater are delivered annually into the southern Chukchi Sea via Bering Strait. We quantify seasonal signals, along with interannual variability, over the course of 26 years of multiple model integrations. Volume transport and property fluxes are evaluated among several high-resolution model runs and compared with available moored observations. High-resolution models represent the bathymetry better, and may have a more realistic representation of the flow through the strait, although in terms of fluxes and mean properties, this is not always the case. We conclude that, (i) while some of the models used for Arctic studies achieve the correct order of magnitude for fluxes of volume, heat and freshwater, and have significant correlations with observational results, there is still a need for improvement and (ii) higher spatial resolution is needed to resolve features such as the Alaska Coastal Current (ACC). At the same time, additional measurements with better spatial coverage are needed to minimize uncertainties in observed estimates and to constrain models.

Progress and Challenges in Biogeochemical Modeling of the Pacific Arctic Region

At this early stage of modeling marine ecosystems and biogeochemical cycles in the Pacific Arctic Region (PAR), numerous challenges lie ahead. Observational data used for model development and validation remain sparse, especially across seasons and under a variety of environmental conditions. Field data are becoming more available, but at the same time PAR is rapidly changing. Biogeochemical models can provide the means to capture some of these changes. This study introduces and synthesizes ecosystem modeling in PAR by discussing differences in complexity and application of one-dimensional, regional, and global earth system models. Topics include the general structure of ecosystem models and specifics of the combined benthic, pelagic, and ice PAR ecosystems, the importance of model validation, model responses to climate influences (e.g. diminishing sea ice, ocean acidification), and the impacts of circulation and stratification changes on PAR ecosystems and biogeochemical cycling. Examples of modeling studies that help place the region within the context of the Pan-Arctic System are also discussed. We synthesize past and ongoing PAR biogeochemical modeling efforts and briefly touch on decision makers’ use of ecosystem models and on necessary future developments.

Toward predictive understanding of the rapidly evolving Arctic Ocean—An overview

Some of the most rapid climate changes on the planet are experienced in the Arctic. In particular, the Arctic has been warming at a quicker pace than any other place on Earth, what is recognized as Arctic Amplification (AA). This warming has been most visibly manifested through a declining perennial sea ice cover, increasing the potential for its transition from the permanent toward a seasonal coverage. Those changes also affect air-sea heat fluxes and amplify ice-albedo feedback, which strongly influences ocean’s absorption of solar radiation. In addition, they also alter the Arctic Ocean acoustical regime, as the thinning sea ice moves faster and deforms easier, while its reduced coverage allows increased momentum transfer from the atmosphere to the upper ocean. This talk will provide an updated overview of the recent changes and trends in the Arctic Ocean of relevance to acoustical oceanography. We will focus on the evolution of the upper ocean stratification and water masses, mesoscale processes, and their linkages to the changing regime of the sea ice cover from multi-year to first-year sea ice. Also, the latest advancements and outstanding challenges in modeling and prediction of Arctic climate change at sub-seasonal to interannual time scales will be discussed.Some of the most rapid climate changes on the planet are experienced in the Arctic. In particular, the Arctic has been warming at a quicker pace than any other place on Earth, what is recognized as Arctic Amplification (AA). This warming has been most visibly manifested through a declining perennial sea ice cover, increasing the potential for its transition from the permanent toward a seasonal coverage. Those changes also affect air-sea heat fluxes and amplify ice-albedo feedback, which strongly influences ocean’s absorption of solar radiation. In addition, they also alter the Arctic Ocean acoustical regime, as the thinning sea ice moves faster and deforms easier, while its reduced coverage allows increased momentum transfer from the atmosphere to the upper ocean. This talk will provide an updated overview of the recent changes and trends in the Arctic Ocean of relevance to acoustical oceanography. We will focus on the evolution of the upper ocean stratification and water masses, mesoscale processes, and ...

The Large Scale Ocean Circulation and Physical Processes Controlling Pacific-Arctic Interactions

Understanding oceanic effects on climate in the Pacific-Arctic region requires knowledge of the mean circulation and its variability in the region. This chapter presents an overview of the mean regional circulation patterns, spatial and temporal variability, critical processes and property fluxes from the northern North Pacific into the western Arctic Ocean, with emphasis on their impact on sea ice. First, results from a high-resolution, pan-Arctic ice-ocean model forced with realistic atmospheric data and observations in the Alaskan Stream, as well as exchanges across the Aleutian Island Passes, are discussed. Next, general ocean circulation in the deep Bering Sea, shelf-basin exchange, and flow across the Bering shelf are investigated. Also, flow across the Chukchi Sea, pathways of Pacific summer water and oceanic forcing of sea ice in the Pacific-Arctic region are analyzed. Finally, we hypothesize that the northward advection of Pacific Water together with the excess oceanic heat that has accumulated below the surface mixed layer in the western Arctic Ocean due to diminishing sea ice cover and subsequent increased solar insolation are critical factors affecting sea ice growth in winter and melt the following year. We argue that process-level understanding and improved model representation of ocean dynamics and ocean-ice-atmosphere interactions in the Pacific-Arctic region are needed to advance knowledge and improve prediction of the accelerated decline of sea ice cover and amplified climate warming in the Arctic.