My name is Ursula Jongebloed (pronounced "youngblood") and I'm a PhD student in Atmospheric Sciences at the University of Washington working with Becky Alexander.
I use ice cores and atmospheric chemistry modeling to understand sulfate aerosol sources and chemistry during the preindustrial and industrial eras. My PhD research can be broadly divided into three topics by source of sulfate aerosols: volcanoes, marine phytoplankton, and human activities.
Passive (i.e. non-eruptive) volcanic degassing is a significant and uncertain source of natural sulfate. We compare ice core volcanic sulfate concentrations to a global chemical transport model and have found that sulfur emissions from passive volcanic degassing are underestimated in global climate models. This result has important implications for sulfate radiative forcing and the global sulfur budget.
Related publications: Jongebloed, et al. (2023), Underestimated passive volcanic sulfur degassing implies overestimated anthropogenic aerosol radiative forcing, Geophysical Research Letters, 50, e2022GL102061. https://doi.org/10.1029/2022GL102061; Jongebloed, U.A. et al. Quantifying Antarctic sulfur sources using the spatial pattern of sulfur isotopes. In prep.
See news articles/podcasts about our GRL paper in NPR's Soundsize Podcast (minutes 5:35 to 16:39), Science Alert, New Scientist, Environmental News Network, UW News, and many others. According to Altmetric, the attention this paper received is in the top 1% of papers published around the same time and top 3% of papers published in GRL!
Marine phytoplankton are primary producers in ocean ecosystems and influence climate through emissions of a sulfur compound called dimethyl sulfide (DMS) to the atmosphere. We use sulfur isotopes to quantify how much sulfate comes from phytoplankton and compare it to methanesulfonic acid, a commonly used proxy for DMS emissions, and find that trends in DMS-derived sulfate do not align with trends in methanesulfonic acid. We use a chemical transport model to explore how DMS oxidation chemistry has changed over the Industrial Era, and how chemistry drives trends in long-term observations of methanesulfonic acid and DMS-derived sulfate.
Related publications: Jongebloed et al. (2023), Industrial-era decline in Arctic methanesulfonic acid is offset by increased biogenic sulfate aerosol. Proceedings of the National Academy of Sciences, 120(47). https://doi.org/10.1073/pnas.2307587120; Jongebloed, U.A. et al. Dimethyl sulfide chemistry over the industrial era: comparison of long-term observations and key gas- and aqueous-phase oxidation mechanisms. In prep.
See a news articles about our PNAS paper in: UW News!
Anthropogenic activities such as fossil fuel burning have increased the abundance of sulfate aerosols to the atmosphere, which have partially offset the warming caused by human greenhouse gases. In recent work, we use a Greenland ice core to quantify how much sulfate comes from anthropogenic activities versus natural sources over the industrial era (Jongebloed et al., 2023 ERL). We also use sulfur and oxygen isotopes of sulfate aerosol samples to investigate pollution sources in Fairbanks, Alaska, which is one of the most polluted cities in the U.S. (Moon et al., 2023).
Related publications: Jongebloed et al. (2023), Quantifying the impact of anthropogenic sulfur emissions on industrial-era Arctic sulfate in a Greenland ice core. Environmental Research Letters. https://doi.org/10.1088/1748-9326/acdc3d; Moon, A.R., Jongebloed, U.A., Dingilian, K.K., Schauer, A.J., Chan, Y.C., Cesler-Maloney, M., et al. (2023). Primary Sulfate Is the Dominant Source of Particulate Sulfate during winter in Fairbanks, Alaska. ACS ES&T Air. https://doi.org/10.1021.acsestair.3c0023.
[9] Jongebloed, U. A., et al. (in prep) Quantifying Antarctic sulfur sources using the spatial pattern of sulfur isotopes.
[8] Jongebloed, U. A., et al. (in prep) Dimethyl sulfide chemistry over the industrial era: comparison of long-term observations and key gas- and aqueous-phase mechanisms.
[7] Chalif, J., Jongebloed, U. A., et al. (in press) Pollution drives enigmatic decline in subarctic biogenic sulfur. In press at Nature Geoscience.
[6] Chan, J., Parasurama, S., Atlas, R., Jongebloed, U. A., Alexander, B., Langenhan, J. M., Thornton, J. A., Riffell, J. A. (2024). Olfaction in the Anthropocene: NO3 negatively affects floral scent and nocturnal pollination. Science, 383(6683), 607-611. https://doi.org/10.1126/science.adi0858
[5] Moon, A., Jongebloed, U. A., Dingilian, K. K., Schauer, A. J., Chan, Y.-C., Cesler-Maloney, M., et al. Sulfur and Oxygen Isotopes Show Primary Sulfate is the Dominant Source of Particulate Sulfate During Winter in Fairbanks, AK, ACS ES&T Air. https://doi.org/10.1021/acsestair.3c00023
[4] Jongebloed, U. A., Schauer, A. J., Cole-Dai, J., Larrick, C. G., Porter, W. C., Tashmim, L., Salimi, S., Edouard, S. R., Geng, L., and Alexander, B. Industrial-era decline in Arctic methanesulfonic acid is offset by increased biogenic sulfate aerosol, Proceedings of the National Academy of Sciences, 120(47). https://doi.org/10.1073/pnas.2307587120
[3] Jongebloed, U. A., Schauer, A. J., Cole-Dai, J., Hattori, S., Larrick, C. G., Salimi, S., Edouard, S. R., Geng, L., and Alexander, B. Sulfur isotopes quantify the impact of anthropogenic activities on industrial-era Arctic sulfate in a Greenland ice core, Environmental Research Letters, https://doi.org/10.1088/1748-9326/acdc3d
[2] Jongebloed, U. A., Schauer, A. J., Cole-Dai, J., Larrick, C. G., Wood, R., Fischer, T. P., Carn, S. A., Salimi, S., Edouard, S. R., Zhai, S., Geng, L., Alexander, B. (2022) Underestimated passive volcanic sulfur degassing implied overestimated aerosol forcing. Geophysical Research Letters, 50, e2022GL102061. https://doi. org/10.1029/2022GL102061
[1] Review paper: Banerjee, A., Riddell-Young, B. E., and Jongebloed, U. A. (2022). Ice-core records of atmospheric composition and chemistry. Past Global Changes Magazine, 104-105, 30(2), https://doi.org/10.22498/pages.30.2.104
[12] Jongebloed, U. A., et al. (2024) Comparison of ice core vs. modeled changes in DMS oxidation products over the industrial era, International GEOS-Chem Meeting, St Louis, MO (poster)
[11] Jongebloed, U. A., et al. (2024) Quantifying Antarctic sulfur sources using the spatial pattern of sulfur isotopes. Ice Core Community Meeting, Portland, ME (talk)
[10] Jongebloed, U. A., et al. (2023) Model-ice core comparison of changes to DMS oxidation chemistry over the industrial era, American Geophysical Fall Meeting, San Francisco, U.S. (poster)
[9] Jongebloed, U. A., et al. (2023) Industrial-era decline in Arctic methanesulfonic acid is offset by increased biogenic sulfate aerosol, U.S. Ice Core Open Science Meeting, Seattle, U.S. (talk)
[8] Jongebloed, U. A., et al. (2022) Industrial-era decline in Arctic methanesulfonic acid is offset by increased biogenic sulfate aerosol, American Geophysical Union Fall Meeting, Chicago, U.S. (poster)
[7] Jongebloed, U. A., et al. (2022) Industrial-era decline in Arctic methanesulfonic acid is offset by increased biogenic sulfate aerosol, International Partnerships in Ice Core Sciences 3rd Open Science Meeting, Crans-Montana, Switzerland (poster)
[6] Jongebloed, U. A., et al. (2022) Underestimated passive volcanic degassing implies overestimated aerosol forcing, St. Louis, MO (poster)
[5] Jongebloed, U. A., et al. (2022) Underestimated passive volcanic degassing implies overestimated aerosol forcing. Ice Core Open Science Meeting, La Jolla, CA (talk).
[4] Jongebloed, U. A., et al. (2021) Preindustrial volcanic emissions are underestimated in climate models: what does this mean for Arctic climate? American Geophysical Union Fall Meeting, New Orleans, LA (talk).
[3] Jongebloed, U. A., et al. (2021) Ice Core Record Indicates Arctic Volcanic Sulfate Aerosols Are Underestimated by Emissions Inventories. Air Pollution in the Arctic: Climate, Environment and Societies (PACES), virtual. (talk).
[2] Jongebloed, U. A., et al. (2017), Elevational and Spatial Gradients of Atmospheric Metal Pollution in the North Pacific. American Geophysical Union Fall Meeting, New Orleans, LA (poster).
[1] Jongebloed, U. A., et al. (2016), Elevated selenium levels follow unprecedented drought in San Francisco Estuary. Bay Delta Science Conference, Sacramento, CA (poster).
Growing up as the daughter of a middle school teacher and granddaughter of three elementary school teachers, education and outreach has always been important to me. I have volunteered as the graduate student coordinator of the UW Atmos Outreach Program, served as a teaching assistant for two classes and lead teaching assistant for four academic quarters, acted as graduate student representative in the UW Program on Climate Change Graduate Steering Committee (see blog post for PCC Spring Symposium), mentored five undergraduate students, and served as a member of the UW Campus Sustainability Fund's program to encourage projects on intersectional sustainability. I also recently co-authored an article for Past Global Changes Magazine on ice-core records of atmospheric composition and chemistry, a review paper intended for a non-expert (e.g. undergraduate or high school) audience. Finally, I am serving as the lead graduate student organizer of the Ice Core Early Career Researcher Workshop 2023 (ICECReW lead organizer in 2023 and 2024, and co-organizer in 2025), which is a professional development workshop for early career researchers with the underlying goal of increasing the inclusivity and accessibility of ice core science.
Download CV here.
