Projections of an Ice-Diminished Arctic Ocean

University Of Washington, Seattle WA

Investigators

Abstract

ABSTRACT OPP-2040916 Zhang Significant changes in arctic climate have been detected in recent years. One of the most striking changes is the decline of sea ice concurrent with changes in atmospheric circulation and increased surface air temperature. This arctic warming trend is likely to continue, as projected by global climate models (GCMs), leading to a diminished arctic sea-ice cover. Diminution of ice cover will have a significant impact on the regional and global climate, and on the socio-economics and ecosystems in the north polar region. It is important to understand the changes that the arctic system has undergone in the past and predict how it will evolve in the future. The Principal Investigators will use a coupled ocean and sea ice model to conduct a retrospective investigation and future projections of the arctic ice-ocean system. The model is global; its grid emphasizes the Arctic Ocean and its linkages to the subarctic oceans. They will investigate the historical and contemporary changes of the Arctic Ocean and the adjacent seas, and to project future changes that are associated with a diminished arctic ice cover under various plausible warming scenarios. There are two science goals: 1) to examine the historical evolution of the arctic system and to understand changes that have occurred in sea ice and the upper ocean in recent decades, and 2) to project a diminished arctic sea-ice cover in future warming scenarios and to examine key linkages among atmospheric forcing, sea-ice processes, and oceanic processes in an ice-diminished Arctic Ocean and the adjacent seas. The project will be done in two-stages: a retrospective investigation, and multiscenario future projections. In the first stage, the Principal Investigators will interpret the large-scale changes that have occurred in sea ice and the upper Arctic Ocean over the past five decades. In the second stage, they will qualitatively and quantitatively examine when, where, and under what circumstances the arctic ice cover is likely to diminish or disappear in the future. They will also study changes in oceanic circulation and processes in an ice-depleted Arctic Ocean and in its interactions with the subarctic oceans. The retrospective investigation complements and expands on other investigations of arctic climate change that use regional models with a limited domain. The future projections of an ice-diminished Arctic Ocean complement GCM projections of possible global warming with Arctic implications. This work will make important contributions to the multi-agency Study of Environmental Arctic Change (SEARCH) effort to understand the large-scale arctic environmental changes that have occurred in the last several decades and to assess possible future changes. Broader Impact: The nature of the work, interpreting the historical and contemporary changes and projecting future trends in the arctic system and its key linkages with the rest of the world ocean, is essential to science, society, and policy formulation. The results will be accessible to researchers and the general public through archival Web pages. The systematic predictions of a retreating sea-ice cover will facilitate scientific studies on biogeochemical and ecosystem changes in the Arctic. Knowledge of the extent, thickness, and duration of the ice cover in the future will have an impact on the livelihood of arctic and subarctic people. The Principal Investigators will provide information about navigability, length of shipping seasons, etc., along the Northern Sea Route and the Northwest Passage and in other arctic areas that are presently seasonally navigable and may become more easily navigable, with a huge impact on economic activities in the north polar region.