APL-UW Home

Jobs
About
Campus Map
Contact
Privacy
Intranet

Jinlun Zhang

Senior Principal Oceanographer

Email

zhang@apl.washington.edu

Phone

206-543-5569

Biosketch

Dr. Zhang is interested in understanding how air-ice-ocean interaction in polar oceans affects polar and global climate. He investigates properties of polar air-ice-ocean systems using large- scale sea ice and ocean models. His recent work has focused on examining the evolution of the sea ice cover and the upper ocean in the Arctic in response to a significant climate change recently observed in the northern polar ocean.

He has developed a coupled global ice-ocean model to study the responses of sea ice to different conditions of surface heat fluxes and the effects of sea ice growth/decay on oceanic thermohaline circulation. He is also interested in developing next-generation sea ice models which capture anisotropic nature of ice dynamics. Dr. Zhang joined the Laboratory in 1994.

Department Affiliation

Polar Science Center

Education

B.S. Shipbuilding & Ocean Engineering, Harbin Shipbuilding Engineering Institute, China, 1982

M.S. Ship Fluid Dynamics & Ocean Engineering, China Ship Scientific Research Center, 1984

Ph.D. Ice and Ocean Dynamics, Thayer School of Engineering, Dartmouth College, 1993

Projects

Changing Sea Ice and the Bering Sea Ecosystem

Part of the BEST (Bering Sea Ecosystem Study) Project, this study will use high-resolution modeling of Bering Sea circulation to understand past change in the eastern Bering climate and ecosystem and to predict the timing and scope of future change.

 

The Arctic Ocean Model Intercomparison Project (AOMIP): Synthesis and Integration

The AOMIP science goals are to validate and improve Arctic Ocean models in a coordinated fashion and investigate variability of the Arctic Ocean and sea ice at seasonal to decadal time scales, and identify mechanisms responsible for the observed changes. The project's practical goals are to maintain and enhance the established AOMIP international collaboration to reduce uncertainties in model predictions (model validation and improvements via coordinated experiments and studies); support synthesis across the suite of Arctic models; organize scientific meetings and workshops; conduct collaboration with other MIPs with a special focus on model improvements and analysis; disseminate findings of AOMIP effort to broader communities; and train a new generation of ocean and sea-ice modelers.

 

The Impact of Changes in Arctic Sea Ice on the Marine Planktonic Ecosystem- Synthesis and Modeling of Retrospective and Future Conditions

This work will investigate the historical and contemporary changes of arctic sea ice, water column, and aspects of the marine ecosystem as an integrated entity, and project future changes associated with a diminished arctic ice cover under several plausible warming scenarios.

 

More Projects

Publications

2000-present and while at APL-UW

Summer sea ice in the Northwestern Chukchi Sea observed in 2024 for the first time in 25 years

Moore, G.W.K., J. Zhang, A. Schweiger, M. Steele, and T.J. Ballinger, "Summer sea ice in the Northwestern Chukchi Sea observed in 2024 for the first time in 25 years," npj Clim. Atmos. Sci., 8, doi:10.1038/s41612-025-01099-5, 2025.

More Info

24 Sep 2025

The Arctic Ocean has seen a profound sea ice loss during the summer, with changes most pronounced in the Western Arctic. This has resulted in the Chukchi Sea, located just north of Bering Strait, being ice-free by the end of summer, i.e. September, since 2000, except during 2024. Here using the ice thickness budget, we investigate the processes responsible for the return of summer sea ice to the region during 2024. We show that an exceptional ice convergence event in February 2024, along with additional events in the winter and spring, resulted in ice thicknesses along the Siberian coast of the Chukchi Sea through the summer months that exceeded values last seen in the region during the late 20th century. The reduced penetration of shortwave radiation through the anomalously thick ice contributed to a delay in melt, contributing to the presence of sea ice in the region during the summer of 2024. We also argue that a thinner and more mobile ice pack contributed to this remarkable return of summer sea ice after a 25-year hiatus, opening the possibility of similar events in the future.

Weaker seasonal variation in potential energy anomaly in the upper Beaufort Gyre favors the upward release of subsurface heat

Zhong, W., M. Steele, J. Zhang, J. Su, and J. Zhao, "Weaker seasonal variation in potential energy anomaly in the upper Beaufort Gyre favors the upward release of subsurface heat," J. Phys. Oceanogr., 55, 1051-1066, doi:10.1175/JPO-D-24-0205.1, 2025.

More Info

6 Jun 2025

The stability of the upper ocean is crucial for the exchange of momentum, heat, and salt between sea ice and subsurface warm water in the Arctic Ocean’s Beaufort Gyre (BG) region. Here, based on multiple in-situ observations, the shifting phases of the BG during 2003–2023 are objectively defined. We find that the potential energy anomaly (PEA) in the upper 55 m decreased from 130.9 ± 2.3 J/m3 during 2006–2012 with BG intensification to 90.3 ± 2.0 J/m3 during 2013–2019 with BG relaxation. Further, the mixed layer became saltier and deeper across all seasons. Decreasing PEA indicates an overall weaker stratification in the upper water column which promotes stronger vertical entrainment. We also find that the mixed layer heat content increased across nearly all seasons, except during July to September (summer). Our analysis using a Price–Weller–Pinkel model suggests that the cause of this warming was not atmospheric heat fluxes from above, but rather subsurface heat entrainment upward. The key mechanism is the seasonal amplitude of PEA is smaller during 2013–2019 when the BG relaxes, thereby allowing mixing to greater depths under the same surface salt flux as in 2006–2012. This is important for the future evolution of the sea ice melting and oceanic vertical mixing if the BG relaxes further.

Effects of early life history traits and warming on Arctic cod prewinter length and recruitment

David, C.L., J.A. Hutchings, Z. Feng, C. Bouchard, I.D. Alabia, H. Hop, J. Zhang, and R. Ji, "Effects of early life history traits and warming on Arctic cod prewinter length and recruitment," Elem. Sci. Anth., 13, doi:10.1525/elementa.2024.00015, 2025.

More Info

10 Apr 2025

The Arctic cod (Boreogadus saida) is a key species in Arctic marine ecosystems, adapted to extreme seasonality and cold environments. The overwintering survival and recruitment of age-0 Arctic cod heavily depend on achieving a sizable prewinter length (PWL) in their first year. Over the growth period, PWL is influenced by early life history traits, such as hatch date and size-at-hatch, and by environmental conditions, such as temperature and food availability. However, our knowledge of these interacting aspects of Arctic cod ecology is extremely limited. Here we coupled an individual-based transport and bioenergetic model with a sea ice-ocean model and simulated larval dispersal and growth under current environmental conditions. In addition, we tested two alternative scenarios of higher temperatures, with +2°C, and lower daily ration by 25% over the growth period. Our modeled PWL aligned well with field data on age-0 Arctic cod lengths by the end of summer. Largest PWLs resulted from winter spawns and were associated with more days with ice cover and shorter embryonic development. Under the high-temperature scenario, average PWL increased in Baffin Bay, Chukchi Sea, and Laptev Sea but declined in Svalbard, suggesting that a portion of age-0 Arctic cod are currently at their thermal tolerance limit. The recruitment success into the juvenile stage, defined as reaching a juvenile threshold length by the end of summer, was maximized in all winter spawns under the high-temperature scenario but decreased to zero in nearly all April spawns across all regions. Under the low-food scenario, reduced prey availability halved the recruitment success in all regions, indicating potentially severe consequences for future Arctic cod growth and survival. Our study illustrates how much changes in sea ice, temperature, and food availability influence the early development of Arctic cod and could impact their recruitment, highlighting the species’ increasingly uncertain future amid rapid environmental changes in the Arctic.

More Publications

In The News

Fact check: NASA did not deny warming or say polar ice has increased since 1979

USA Today, Kate Petersen

NASA researchers have documented the loss of trillions of tons of ice from Earth's poles due to human-driven climate change. Citing published reports from the Polar Science Center and other sources, popular social media memes claiming an increase in polar ice since 1979 are swatted down.

21 Jan 2022

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

More News Items

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center
Close

 

Close