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Ignatius Rigor

Senior Principal Research Scientist

Affiliate Assistant Professor, Oceanography






Ignatius Rigor is the Coordinator of the International Arctic Buoy Program (IABP). His primary interests are in the use of data from the buoys to study air, sea, and ice interaction. His recent work has focused on analyzing surface air temperature observations in the Arctic, studying sea ice processes in the Russian marginal seas, and backtracking the source areas of pollutants found in sea ice. He joined the professional staff in 1987 after having worked in the APL-UW Student Assistant Program as an undergraduate.

Department Affiliation

Polar Science Center


B.S. Biology, University of Washington, 1986


International Arctic Buoy Programme

The participants of the IABP work together to maintain a network of drifting buoys in the Arctic Ocean to provide meteorological and oceanographic data for real-time operational requirements and research purposes including support to the World Climate Research Programme and the World Weather Watch Programme.


Sea Ice Thickness Estimates Obtained from Satellites Using Submarines and Other In Situ Observations

We compare the observations of arctic sea ice thickness estimates from satellites with in situ observations %u2013 collected by submarine cruises and moorings under the sea ice, by direct measurement during field camps, by electromagnetic instruments flown over the sea ice, and by buoys drifting with the sea ice %u2013 to provide a careful assessment of our capabilities to monitor the thickness of sea ice.


Arctic Surface Air Temperatures for the Past 100 Years

Accurate fields of Arctic surface air temperature (SAT) are needed for climate studies, but a robust gridded data set of SAT of sufficient length is not available over the entire Arctic. We plan to produce authoritative SAT data sets covering the Arctic Ocean from 1901 to present, which will be used to better understand Arctic climate change.


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International Cooperative Engagement Program for Polar Research

An international team dropped buoys by parachute from a C-130 operated by the Danish Royal Air Force. These buoys are floating weather stations that measure fundamental meteorological properties. Satellite-linked data are used to forecast weather, track sea ice movement, and study climate change in the Arctic. The September 2017 buoy drops enhanced the 100-buoy arctic network by targeting sparsely sampled regions near the North Pole and the Eurasian side of the Arctic Ocean.

30 Oct 2017

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.

Snow Accumulations on Arctic Sea Ice

Snow plays a key role in the growth and decay of Arctic sea ice each year. APL-UW research assesses spring snow depth distribution on Arctic sea ice using airborne radar observations from Operation IceBridge compared with in situ measurements taken in spring 2012 and historical data from the Soviet drifting ice stations of the mid-20th century. Snow depths have declined in the western Arctic and Beaufort and Chukchi seas. Thinning is correlated with the delayed onset of sea ice freeze-up during autumn.

11 Sep 2014

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2000-present and while at APL-UW

Increased fluxes of shelf-derived materials to the central Arctic Ocean

Kipp, L.E., M.A. Charette, W.S. Moore, P.B. Henderson, and I.G. Rigor, "Increased fluxes of shelf-derived materials to the central Arctic Ocean," Sci. Adv., 4, eaao1302, doi:10.1126/sciadv.aao1302, 2018.

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3 Jan 2018

Rising temperatures in the Arctic Ocean region are responsible for changes such as reduced ice cover, permafrost thawing, and increased river discharge, which, together, alter nutrient and carbon cycles over the vast Arctic continental shelf. We show that the concentration of radium-228, sourced to seawater through sediment–water exchange processes, has increased substantially in surface waters of the central Arctic Ocean over the past decade. A mass balance model for 228Ra suggests that this increase is due to an intensification of shelf-derived material inputs to the central basin, a source that would also carry elevated concentrations of dissolved organic carbon and nutrients. Therefore, we suggest that significant changes in the nutrient, carbon, and trace metal balances of the Arctic Ocean are underway, with the potential to affect biological productivity and species assemblages in Arctic surface waters.

Geophysical constraints on the Antarctic sea ice cover

Nghiem, S.V., I.G. Rigor, P. Clemente-Colón, G. Neumann, and P.P. Li, "Geophysical constraints on the Antarctic sea ice cover," Remote Sens. Environ., 181, 281-292, doi:10.1016/j.rse.2016.04.005, 2016.

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1 Aug 2016


The stark contrast between Arctic and Antarctic sea ice change is explained.

Observations show a frontal ice zone protecting and enhancing Antarctic sea ice.

The frontal ice zone is strongly influenced by winds and ocean fronts.

Antarctic winds are controlled by topography and ocean fronts by bathymetry.

Topography/bathymetry are stable geological factors constraining Antarctic sea ice.

Interannual variations of light-absorbing particles in snow on Arctic sea ice

Doherty, S.J., M. Steele, I. Rigor, and S.G. Warren, "Interannual variations of light-absorbing particles in snow on Arctic sea ice," J. Geophys. Res., 120, 11,391-11,400, doi:10.1002/2015JD024018, 2015.

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16 Nov 2015

Samples of snow on sea ice were collected in springtime of the 6 years 2008–2013 in the region between Greenland, Ellesmere Island, and the North Pole (82°N – 89°N, 0°W – 100°W). The meltwater was passed through filters, whose spectral absorption was then measured to determine the separate contributions by black carbon (BC) and other light-absorbing impurities. The median mixing ratio of BC across all years' samples was 4 ± 3 ng g-1, and the median fraction of absorption due to non-BC absorbers was 36 ± 11%. Variances represent both spatial and interannual variability; there was no interannual trend in either variable. The absorption Angstrom exponent, however, decreased with latitude, suggesting a transition from dominance by biomass-burning sources in the south to an increased influence by fossil-fuel-burning sources in the north, consistent with earlier measurements of snow in Svalbard and at the North Pole.

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In The News

Evidence mounts against so-called climate change hiatus

Live Science, Laura Geggel

Evidence is mounting against the so-called climate change hiatus — a period lasting from 1998 to 2012 — when global temperatures allegedly stopped rising as sharply as they had before. Data collected by scientists from the APL-UW Polar Science Center were used in the recent study.

22 Nov 2017

Fra Aalborg til Nordpolen: Paa mission for NASA (with video)

TV2 Nord (Denmark), Lasse Dieckmann

Ice-hardened buoys, known as Air Expendable Ice Beacons (AXIB), were deployed in the Arctic Ocean near the North Pole from a Royal Danish Airforce C-130 aircraft flying out of Thule Air Base in Greenland.

13 Sep 2017

U.S. Navy leads international effort to deploy buoys into the Arctic Ocean

U.S. Navy News Service

Air-Deployable Expendable Ice Buoys are deployed in the high Arctic near the North Pole from a Royal Danish Air Force C-130 aircraft operating out of Thule Air Force Base in Greenland, as part of the International Arctic Buoy Program (IABP).

12 Sep 2017

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