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Mike Steele

Senior Principal Oceanographer






Dr. Steele is interested in the large-scale circulation of sea ice and water in the Arctic Ocean. He uses both observed data and numerical model simulations to better understand the average circulation pathways as well as the causes of interannual variations in these pathways. Analysis of ocean observations has focused on the upper layers, which are generally quite cold and fresh.

Dr. Steele has active field programs in which data are collected in the field by his team and others, using aircraft, ships, and autonomous sensors like buoys and profiling floats. He is also involved with efforts to improve computer models of the arctic marine system, via the Arctic Ocean Model Intercomparison Project, AOMIP.

Funding for his research comes from the National Science Foundation, NASA, and the National Oceanic and Atmospheric Agency (NOAA). He is involved with many outreach programs such as lectures to K-12 and college students. Mike Steele began work at the Polar Science Center in 1987.

Department Affiliation

Polar Science Center


B.A. Physics, Reed College, 1981

Ph.D. Geophysical Fluid Dynamics, Princeton University, 1987


North Pole Environmental Observatory

The observatory is staffed by an international research team that establishes a camp at the North Pole each spring to take the pulse of the Arctic Ocean and learn how the world's northernmost sea helps regulate global climate.


Producing an Updated Synthesis of the Arctic's Marine Primary Production Regime and its Controls

The focus of this project is to synthesize existing studies and data relating to Arctic Ocean primary production and its changing physical controls such as light, nutrients, and stratification, and to use this synthesis to better understand how primary production varies in time and space and as a function of climate change.


A Modular Approach to Building an Arctic Observing System for the IPY and Beyond in the Switchyard Region of the Arctic Ocean

This project will provided for the design, development, and implementation of a component of an Arctic Ocean Observing System in the Switchyard region of the Arctic Ocean (north of Greenland and Nares Strait) that will serve the scientific studies developed for the IPY (International Polar Year), SEARCH (Study of Environmental ARctic Change), and related programs. Specifically, the project will continue and expand two aircraft-based sections between Alert and the North Pole for long-term observation of hydrographic properties and a set of tracers aimed at resolving relative age structure and freshwater components in the upper water column.


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Polar Science Weekend @ Pacific Science Center

This annual event at the Pacific Science Center shares polar science with thousands of visitors. APL-UW researchers inspire appreciation and interest in polar science through dozens of live demonstrations and hands-on activities.

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10 Mar 2017

Polar research and technology were presented to thousands of visitors by APL-UW staff during the Polar Science Weekend at Seattle's Pacific Science Center. The goal of is to inspire an appreciation and interest in science through one-on-one, face-to-face interactions between visitors and scientists. Guided by their 'polar passports', over 10,000 visitors learned about the Greenland ice sheet, the diving behavior of narwhals, the difference between sea ice and freshwater ice, how Seagliders work, and much more as they visited dozens of live demonstrations and activities.

The Polar Science Weekend has grown from an annual outreach event to an educational research project funded by NASA, and has become a model for similar activities hosted by the Pacific Science Center. A new program trains scientists and volunteers how to interact with the public and how to design engaging exhibits.

Arctic Sea Ice Extent and Volume Dip to New Lows

By mid-September, the sea ice extent in the Arctic reached the lowest level recorded since 1979 when satellite mapping began.

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15 Oct 2012

APL-UW polar oceanographers and climatologists are probing the complex ice–ocean–atmosphere system through in situ and remote sensing observations and numerical model simulations to learn how and why.

Changing Freshwater Pathways in the Arctic Ocean

Freshening in the Canada Basin of the Arctic Ocean began in the 1990s. Polar scientist Jamie Morison and colleagues report new insights on the freshening based in part on Arctic-wide views from two satellite system.

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5 Jan 2012

The Arctic Ocean is a repository for a tremendous amount of river runoff, especially from several huge Russian rivers. During the spring of 2008, APL-UW oceanographers on a hydrographic survey in the Arctic detected major shifts in the amount and distribution of fresh water. The Canada basin had freshened, but had the entire Arctic Ocean?

Analysis of satellite records shows that salinity increased on the Russian side of the Arctic and decreased in the Beaufort Sea on the Canadian side. With an Arctic-wide view of circulation from satellite sensors, researchers were able to determine that atmospheric forcing had shifted the transpolar drift counterclockwise and driven Russian runoff east to the Canada Basin.

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2000-present and while at APL-UW

Examining the consistency of sea surface temperature and sea ice concentration in Arctic satellite products

Castro, S.L., G.A. Wick, S. Eastwood, M.A. Steele, and R.T. Tonboe, "Examining the consistency of sea surface temperature and sea ice concentration in Arctic satellite products," Remote Sens., 15, doi:10.3390/rs15112908, 2023.

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2 Jun 2023

Available observations and a theoretical simulation are used to explore the consistency and relationship between sea surface temperature (SST) and sea ice concentration (SIC) within open-ocean-sea ice mixed satellite pixels as a function of grid resolution. The maximum limiting SST value for a specified SIC and spatial resolution is first examined within collocated satellite-derived products contained within existing Level 4 SST analyses distributed using the data specification from the Group for High Resolution Sea Surface Temperature. The shape of the interdependence is further validated with manually quality-controlled buoy SST and SIC collocations. A parametric equation for the limiting SST value is derived from simulations of a mixed ocean/ice pixel with specified ice fraction and a linear SST gradient extending away from the ice edge. The exponential curve matching the observed interdependence suggests a maximum 5 km pixel-averaged SST at SIC values approaching zero between 6 and 8°C. This maximum value is significantly greater than the previously assumed limiting values of ~3°C and the corresponding SST gradient is larger than those typically observed with satellite SST products, but agrees well with recent Saildrone SST observations near ice. The curve provides a conservative limit with which inconsistent SST/SIC pairings can be identified, not only near the ice edge but at intermediate ice concentrations. Application of the filter improves the agreement between the SST/SIC relationship in satellite products and available Saildrone observations as well as the internal consistency of the different satellite products.

Clouds increasingly influence Arctic sea surface temperatures as CO2 rises

Sledd, A., T.S. L'Ecuyer, J.E. Kay, and M. Steele, "Clouds increasingly influence Arctic sea surface temperatures as CO2 rises," Geophys. Res. Lett., 50, doi:10.1029/2023GL102850, 2023.

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28 Apr 2023

As Arctic sea ice retreats during the melt season, the upper ocean warms in response to atmospheric heat fluxes. Overall, clouds reduce these fluxes in summer, but how the radiative impacts of clouds on ocean warming could change as sea ice declines has not been documented. In global climate model simulations with variable CO2, the timing of sea ice retreat strongly influences the amplitude of cloud-induced summer cooling at the ocean surface. Under pre-industrial CO2 concentrations, summer clouds have little direct effect on maximum annual sea surface temperatures (SST). When CO2 concentrations increase, sea ice retreats earlier, allowing more solar radiation to warm the ocean. Clouds can counteract this summer warming by reflecting solar radiation back to space. Consequently, clouds explain up to 13% more variability in maximum annual SST under modern-day CO2 concentrations. Maximum annual SST are three times more sensitive to summer clouds when CO2 concentrations are four times pre-industrial levels.

Asymmetrically stratified Beaufort Gyre: Mean state and response to decadal forcing

Zhang, J., W. Cheng, M. Steele, and W. Weijer, "Asymmetrically stratified Beaufort Gyre: Mean state and response to decadal forcing," Geophys. Res. Lett., 50, doi:10.1029/2022GL100457, 2023.

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16 Jan 2023

Recent progress in understanding Beaufort Gyre (BG) dynamics reveals an important role of ice-ocean stress in stabilizing BG freshwater content (FWC) over seasonal to interannual timescales. But how the BG's stratification and FWC respond to surface forcing over decadal timescales has not been fully explored. Using a global ocean-sea ice model, we partition the BG into upper, middle (halocline), and lower (thermocline) layers and perform a volume budget analysis over 1948–2017. We find that the BG's asymmetric geometry (with steep and tight isohalines over continental slopes relative to the deep basin) is key in determining the mean volume transport balance. We further find that a net Ekman suction during 1983–1995 causes the upper and middle layers to deflate isopycnally, while an enhanced Ekman pumping during 1996–2017 causes these layers to inflate both isopycnally and diapycnally, the latter via anomalous flux from the upper to the middle layer.

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In The News

Arctic's 'last ice area' may be less resistant to global warming

The New York Times, Henry Fountain

The region, which could provide a last refuge for polar bears and other Arctic wildlife that depends on ice, is not as stable as previously thought, according to a new study.

1 Jul 2021

Arctic's 'last ice area' shows earlier-than-expected melt

Associated Press, Seth Borenstein

Part of the Arctic is nicknamed the 'Last Ice Area,' because floating sea ice there is usually so thick that it’s likely to withstand global warming for decades. So, scientists were shocked last summer when there was suddenly enough open water for a ship to pass through.

1 Jul 2021

Climate change: 'Last refuge' for polar bears is vulnerable to warming

BBC News, Matt McGrath

The region, dubbed the 'last ice area' had been expected to stay frozen far longer than other parts of the Arctic. But new analysis says that this area suffered record melting last summer. The researchers say that high winds allied to a changing climate were behind the unexpected decline.

1 Jul 2021

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