Collaborative Research: EAGER: Microstructure Observations of Vertical Mixing and Heat Fluxes from Chipods Deployed on Arctic Observing Network Cruises

University Of Washington, Seattle WA

Investigators

Abstract

Climate change is causing the Arctic Ocean to get warmer and Arctic sea ice to melt. These two effects are related, because a warmer ocean can melt sea ice faster, and when sea ice melts, more sunlight gets into the ocean, making it even warmer. Melted sea ice may also result in more ocean turbulence as it allows for bigger waves on the ocean surface. We do not fully understand how melting sea ice and a warming ocean influence each other, and it is difficult to make ocean measurements in the Arctic Ocean. Here we propose to use an existing dataset of turbulence observations to understand whether warming of Arctic waters is associated with ocean mixing, to identify regional patterns in mixing, and to quantify changes in recent years. These observations were made with a highly specialized instrument that can directly measure ocean turbulence, which has been infrequently used in the Arctic Ocean. Part of the proposed work is to develop new methods to interpret the data in this unique environment. Once these methods are developed, they may make long term monitoring of changes in Arctic turbulence possible. The motivation driving this work is to improve understanding of how Arctic climate change will affect interactions between the ocean and sea ice. This is an important goal both for Arctic coastal communities, who face a loss of sea ice and increasing coastal erosion, and for improving predictions of global climate. The proposal will support the early careers of two female scientists, and will also support a collaboration with the Birch Aquarium to develop an exhibit to explain Arctic climate change to a broad audience. Climate change is dramatically altering the Arctic Ocean, including the multidecadal loss of Arctic sea ice. Understanding potential feedbacks between sea ice loss and the warming Arctic Ocean is of critical importance to predicting and mitigating future climate change. Here we propose to use an existing dataset of 264 profiles of shipboard turbulence observations collected on two Arctic Observing Network cruises to assess the strength of vertical mixing in boundary current regions of the Arctic Ocean, and quantify any correlation between the strength of mixing and temperature of boundary currents (which have warmed in recent years); and identify regional patterns in mixing along the Arctic shelves and quantify any changes in mixing rates relative to prior studies. We aim to use the results to both improve our understanding of Arctic ocean mixing in a warming climate and inform future efforts to monitor changes in the Arctic mixing environment. These deployments represent some of the first uses of turbulence instruments in the Arctic ocean which can be routinely deployed on hydrography cruises, and processing and interpreting the resulting data will require new methods due to differences between the Arctic ocean and the lower latitude oceans where these instruments are usually deployed. Once completed, this analysis will provide information about changes in Arctic oceanic vertical mixing and how the vertical transport of heat and nutrients will evolve in a changing climate. The underlying objective of this work is to improve understanding of the Arctic climate and its likely trajectory in terms of vertical mixing rates along the margins. This aim is important regionally, as Arctic coastal communities face a loss of sea ice and coastal erosion, and globally for improving predictions of the future climate. Additionally, this proposal is structured to support the early careers of two female scientists, and will also support a collaboration with the Birch Aquarium to develop an exhibit to explain Arctic climate change to a broad audience. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.