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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 - Seattle, 1986

M.S. Atmospheric Science, University of Washington - Seattle, 2001

Ph.D. Atmospheric Science, University of Washington - Seattle, 2005


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

The cyclonic mode of Arctic Ocean circulation

Morison, J., R. Kwok, S. Dickinson, R. Andersen, C. Peralta-Ferriz, D. Morison, I. Rigor, S. Dewey, and J. Guthrie, "The cyclonic mode of Arctic Ocean circulation," J. Phys. Oceanogr., EOR, doi:10.1175/JPO-D-20-0190.1, 2021.

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20 Jan 2021

Arctic Ocean surface circulation change should not be viewed as the strength of the anticyclonic Beaufort Gyre. While the Beaufort Gyre is a dominant feature of average Arctic Ocean surface circulation, empirical orthogonal function analysis of dynamic height (1950–1989) and satellite altimetry-derived dynamic ocean topography (2004–-2019) show the primary pattern of variability in its cyclonic mode is dominated by a depression of the sea surface and cyclonic surface circulation on the Russian side of the Arctic Ocean. Changes in surface circulation after AO maxima in 1989 and 2007–08 and after an AO minimum in 2010, indicate the cyclonic mode is forced by the Arctic Oscillation (AO) with a lag of about one year. Associated with a one standard deviation increase in the average AO starting in the early 1990s, Arctic Ocean surface circulation underwent a cyclonic shift evidenced by increased spatial-average vorticity. Under increased AO, the cyclonic mode complex also includes increased export of sea ice and near-surface freshwater, a changed path of Eurasian runoff, a freshened Beaufort Sea, and weakened cold halocline layer that insulates sea ice from Atlantic water heat, an impact compounded by increased Atlantic Water inflow and cyclonic circulation at depth. The cyclonic mode's connection with the AO is important because the AO is a major global scale climate index predicted to increase with global warming. Given the present bias in concentration of in situ measurements in the Beaufort Gyre and Transpolar Drift, a coordinated effort should be made to better observe the cyclonic mode.

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.

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.

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In The News

Al Roker travels to the Arctic for a firsthand look at climate change

Today on NBC, Eun Kyung Kim

Al Roker travels to the farthest north town in the country to speak with scientists studying climate change. At a weather station on the sea ice, Ignatius Rigor tells Roker that the temperature changes observed in the Arctic are unprecedented because they have happened in only 30–50 years.

1 Apr 2019

Here's what vanishing sea ice in the Arctic means for you

The Verge, Alessandra Potenza

The mainstream news website, The Verge, interview Ignatius Rigor from APL-UW Polar Science Center and other researchers to detail the many ways the decreasing sea ice in the Arctic impacts the general public.

10 May 2018

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

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