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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

Half a century of satellite remote sensing of sea-surface temperature

Minnett, P.J., and 13 others including M. Steele, "Half a century of satellite remote sensing of sea-surface temperature," Remote Sens. Environ., 233, 111366, doi:10.1016/j.rse.2019.111366, 2019.

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1 Nov 2019

Sea-surface temperature (SST) was one of the first ocean variables to be studied from earth observation satellites. Pioneering images from infrared scanning radiometers revealed the complexity of the surface temperature fields, but these were derived from radiance measurements at orbital heights and included the effects of the intervening atmosphere. Corrections for the effects of the atmosphere to make quantitative estimates of the SST became possible when radiometers with multiple infrared channels were deployed in 1979. At the same time, imaging microwave radiometers with SST capabilities were also flown. Since then, SST has been derived from infrared and microwave radiometers on polar orbiting satellites and from infrared radiometers on geostationary spacecraft. As the performances of satellite radiometers and SST retrieval algorithms improved, accurate, global, high resolution, frequently sampled SST fields became fundamental to many research and operational activities. Here we provide an overview of the physics of the derivation of SST and the history of the development of satellite instruments over half a century. As demonstrated accuracies increased, they stimulated scientific research into the oceans, the coupled ocean-atmosphere system and the climate. We provide brief overviews of the development of some applications, including the feasibility of generating Climate Data Records. We summarize the important role of the Group for High Resolution SST (GHRSST) in providing a forum for scientists and operational practitioners to discuss problems and results, and to help coordinate activities world-wide, including alignment of data formatting and protocols and research. The challenges of burgeoning data volumes, data distribution and analysis have benefited from simultaneous progress in computing power, high capacity storage, and communications over the Internet, so we summarize the development and current capabilities of data archives. We conclude with an outlook of developments anticipated in the next decade or so.

Snowpack measurements suggest role for multi-year sea ice regions in Arctic atmospheric bromine and chlorine chemistry

Peterson, P.K., M. Hartwig, N.W. May, E. Schwartz, I. Rigor, W. Ermold, M. Steele, J.H. Morison, S.V. Nghiem, and K.A. Pratt, "Snowpack measurements suggest role for multi-year sea ice regions in Arctic atmospheric bromine and chlorine chemistry," Elem. Sci. Anth., 7 doi:10.1525/elementa.352, 2019.

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3 May 2019

As sources of reactive halogens, snowpacks in sea ice regions control the oxidative capacity of the Arctic atmosphere. However, measurements of snowpack halide concentrations remain sparse, particularly in the high Arctic, limiting our understanding of and ability to parameterize snowpack participation in tropospheric halogen chemistry. To address this gap, we measured concentrations of chloride, bromide, and sodium in snow samples collected during polar spring above remote multi-year sea ice (MYI) and first-year­ sea ­ice ­(FYI) ­north ­of ­Greenland­ and ­Alaska, ­as­ well­ as ­in ­the ­central ­Arctic, ­and ­compared these measurements to a larger dataset collected in the Alaskan coastal Arctic by Krnavek et al. (2012). Regardless of sea ice region, these surface snow samples generally featured lower salinities, compared to­ coastal ­snow. ­­Surface­ snow­ in ­FYI­ regions ­was ­typically­ enriched ­in bromide ­and­ chloride ­compared ­to seawater, indicating snowpack deposition of bromine and chlorine-containing trace gases and an ability of the snowpack to participate further in bromine and chlorine activation processes. In contrast, surface snow in MYI regions was more often depleted in bromide, indicating it served as a source of bromine-containing trace gases to the atmosphere prior to sampling. Measurements at various snow depths indicate that the deposition of sea salt aerosols and halogen-containing trace gases to the snowpack surface played a larger role in determining surface snow halide concentrations compared to upward brine migration from sea ice. Calculated enrichment factors for bromide and chloride, relative to sodium, in the MYI snow­ samples ­suggests ­that ­MYI­ regions, ­in addition ­to ­FYI­ regions, ­have ­the ­potential ­to ­play ­an ­active role in Arctic boundary layer bromine and chlorine chemistry. The ability of MYI regions to participate in springtime atmospheric halogen chemistry should be considered in regional modeling of halogen activation and interpretation of satellite-based tropospheric bromine monoxide column measurements.

Regional variability of arctic sea ice seasonal change climate indicators from a passive microwave climate data record

Bliss, A.C., M. Steele, G. Peng, W.N. Meier, and S. Dickinson, "Regional variability of arctic sea ice seasonal change climate indicators from a passive microwave climate data record," Environ. Res. Lett., 14, doi:10.1088/1748-9326/aafb84, 2019.

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26 Mar 2019

The seasonal evolution of Arctic sea ice can be described by the timing of key dates of sea ice concentration (SIC) change during its annual retreat and advance cycle. Here, we use SICs from a satellite passive microwave climate data record to identify the sea ice dates of opening (DOO), retreat (DOR), advance (DOA), and closing (DOC) and the periods of time between these events. Regional variability in these key dates, periods, and sea ice melt onset and freeze-up dates for 12 Arctic regions during the melt seasons of 1979–2016 is investigated. We find statistically significant positive trends in the length of the melt season (outer ice-free period) for most of the eastern Arctic, the Bering Sea, and Hudson and Baffin Bays with trends as large as 11.9 d decade-1 observed in the Kara Sea. Trends in the DOR and DOA contribute to statistically significant increases in the length of the open water period for all regions within the Arctic Ocean ranging from 3.9 to 13.8 d decade-1. The length of the ice retreat period (DOR−DOO) ranges from 17.1 d in the Sea of Okhotsk to 41 d in the Greenland Sea. The length of the ice advance period (DOC–DOA) is generally much shorter and ranges from 17.9 to 25.3 d in the Sea of Okhotsk and Greenland Sea, respectively. Additionally, we derive the extent of the seasonal ice zone (SIZ) and find statistically significant negative trends (SIZ is shrinking) in the Sea of Okhotsk, Baffin Bay, Greenland Sea, and Barents Sea regions, which are geographically open to the oceans and influenced by reduced winter sea ice extent. Within regions of the Arctic Ocean, statistically significant positive trends indicate that the extent of the SIZ is expanding as Arctic summer sea ice declines.

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In The News

February's big patch of open water off Greenland? Not global warming, says new analysis

UW News, Hannah Hickey

In February 2018, a vast expanse of open water appeared in the sea ice above Greenland, a region that normally has sea ice well into the spring. The big pool of open water in the middle of the ice, known as a polynya, was a scientific puzzle.

18 Dec 2018

Seattle climate scientists spread word on warming, skip politics

The Seattle Times, Jerry Large

Climate scientists at the University of Washington want to talk more about their work because it and public policy are intertwined. They stick to the science side of the equation, which they want the rest of us to understand better so that we can make informed decisions about climate change.

12 Jan 2017

Cyclone did not cause 2012 record low for Arctic sea ice

UW News and Information, Hannah Hickey

"The Great Arctic Cyclone of August 2012," is thought by some to have led to the historic sea ice minimum reached in mid-September 2013. UW research suggests otherwise.

31 Jan 2013

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