Profiles

John Prytherch

Forskare

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Works at Department of Meteorology
Telephone 08-16 43 73
Email john.prytherch@misu.su.se
Visiting address Svante Arrhenius väg 16 C
Postal address Meteorologiska institutionen (MISU) 106 91 Stockholm

About me

My role is part of the Arctic Climate Across Scales (ACAS) project, funded by the Knut & Alice Wallenberg Foundation, aiming to explore the linkages of physical processes important for the Arctic climate across several spatial and temporal scales.

Formal responsibilities

  • Design, construction and operation of an Arctic meteorological observatory on the icebreaker Oden, comprising semi-autonomous in situ and surface-based remote sensing instrumentation.
  • Publication of quality-controlled observations on open-data archives.
  • Assistance with instrumentation, logging systems, etc.

Research interests

  • Air-sea interaction
  • Upper-ocean physics

The current focus of my research is the exchange of trace gases (e.g. CO2, methane) between the ocean and the atmosphere at high latitude. In particular, the role of sea ice.

Publications

A selection from Stockholm University publication database
  • 2017. John Prytherch (et al.). Geophysical Research Letters 44 (8), 3770-3778

    The Arctic Ocean is an important sink for atmospheric CO2. The impact of decreasing sea ice extent and expanding marginal ice zones on Arctic air-sea CO2 exchange depends on the rate of gas transfer in the presence of sea ice. Sea ice acts to limit air-sea gas exchange by reducing contact between air and water but is also hypothesized to enhance gas transfer rates across surrounding open-water surfaces through physical processes such as increased surface-ocean turbulence from ice-water shear and ice-edge form drag. Here we present the first direct determination of the CO2 air-sea gas transfer velocity in a wide range of Arctic sea ice conditions. We show that the gas transfer velocity increases near linearly with decreasing sea ice concentration. We also show that previous modeling approaches overestimate gas transfer rates in sea ice regions.

  • 2017. B. W. Blomquist (et al.). Journal of Geophysical Research - Oceans 122 (10), 8034-8062

    A variety of physical mechanisms are jointly responsible for facilitating air-sea gas transfer through turbulent processes at the atmosphere-ocean interface. The nature and relative importance of these mechanisms evolves with increasing wind speed. Theoretical and modeling approaches are advancing, but the limited quantity of observational data at high wind speeds hinders the assessment of these efforts. The HiWinGS project successfully measured gas transfer coefficients (k(660)) with coincident wave statistics under conditions with hourly mean wind speeds up to 24 m s(-1) and significant wave heights to 8 m. Measurements of k(660) for carbon dioxide (CO2) and dimethylsulfide (DMS) show an increasing trend with respect to 10 m neutral wind speed (U-10N), following a power law relationship of the form: k660CO2 approximate to U10N1.68 and k660dms approximate to U10N1.33. Among seven high wind speed events, CO2 transfer responded to the intensity of wave breaking, which depended on both wind speed and sea state in a complex manner, with k660CO2 increasing as the wind sea approaches full development. A similar response is not observed for DMS. These results confirm the importance of breaking waves and bubble injection mechanisms in facilitating CO2 transfer. A modified version of the Coupled Ocean-Atmosphere Response Experiment Gas transfer algorithm (COAREG ver. 3.5), incorporating a sea state-dependent calculation of bubble-mediated transfer, successfully reproduces the mean trend in observed k(660) with wind speed for both gases. Significant suppression of gas transfer by large waves was not observed during HiWinGS, in contrast to results from two prior field programs.

Show all publications by John Prytherch at Stockholm University

Last updated: December 20, 2017

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