C03: Atmospheric composition and ocean colour feedback to Arctic amplification
As a result of the retreat of sea ice in a warming climate, the underwater ultraviolet (UV) and photosynthetically active radiation and, thus, the type and amount of phytoplankton and coloured dissolved organic matter (CDOM) are changing. This impacts on the radiation emitted by the ocean and the emissions of organohalogens from specific phytoplankton groups (PG) and CDOM. In the cryosphere, halogens and interhalogens are released by an inorganic auto-catalytic heterogenous mechanism from areas of potential frost flower growth, younger sea ice and blowing snow. The halogen atoms deplete ozone, a significant greenhouse gas and through its photolysis a source of OH, the most important tropospheric oxidising agent. The oxidising capacity and radiative forcing of the troposphere are thus impacted. Halogen atoms and oxides react with and remove gaseous mercury, which is toxic and has adverse environmental impacts. Iodine monoxide (IO) reacts to form hygroscopic higher oxides, which act as cloud condensation nuclei (CCN). The changes in phytoplankton, CDOM and halogen abundance are linked and respond to and feed back on Arctic amplification.
Optical passive remote sensing instrumentation on satellite platforms yields unique information about ocean colour, bromine monoxides (BrO) and potentially IO in the remote Arctic region during the polar day. This project builds on the outcomes of project C03 in phase I, including unique multi-sensor long-term consolidated and consistent datasets of BrO, light attenuation (kd) and PG. The data was retrieved from GOME (1996-2003), SCIAMACHY (2002-2012), GOME-2A (2007-present), GOME-2B (2013-present) for BrO and kd, and by synergistic use of SCIAMACHY and multispectral satellite sensors for high resolution PG data. The first high spatial resolution retrievals of BrO were developed for the new Sentinel-5P (S5P, 2017-present) and radiative transfer modelling was extended to include radiative feedbacks from the ocean to the atmosphere. Analysis of the long-term datasets, in combination with in–situ observations, indicates (i) changes towards smaller sized and increased growth of PG but reduced carbon export in the Fram Strait over the last ten years, (ii) a signiicant radiative feedback to the atmosphere caused by high light absorption in the surface ocean due to increasing CDOM loading in the Laptev Sea and (iii) increasing amounts of BrO in the Arctic troposphere. In phase II, the new datasets and related analysis are planned to be extended and refined using higher spatial resolution measurements. Ice ocean biogeochemistry (BGC) models will be adapted to derive year-round ocean colour data and oceanic aerosol predictions. Lagrangian transport simulations will be carried out in order to relate observed halogen plumes to drivers of the latter. The primary objective is to improve the understanding of temporal changes of halogen oxides, PG, related carbon fluxes, aerosol precursor emissions, and the induced radiative feedback caused by increasing temperatures in the Arctic.
Changes in atmospheric trace gases/particles and surface ocean constituents are influenced by and feed back to Arctic amplification on different spatial and temporal scales, through their impact on radiative forcing and oxidative capacity.
Studies will focus on the following central questions:
- Will the net observed increases of tropospheric BrO, phytoplankton biomass (CHL), small PG and CDOM stabilise/reverse during the next years?
- What are the main spatial and temporal scales of changes and drivers (e.g., microscale cracks in ice, synoptic scale cyclones, SST, oceanic radiation) and how are they linked?
- What is the impact of indirect effects of changing surface water BGC on atmospheric radiative forcing via aerosol precursor emissions?
Achievements phase I
In C03 first consistent, long-term, and multi-sensor data sets of phytoplankton groups (PG) and BrO over the Arctic were obtained. The time series revealed changes over the last ten years towards smaller sized and increased growth of PG, but reduced carbon export in the Fram Strait (Engel et al., 2019). Furthermore, a close link between a bromine explosion event and polar cyclone development was discovered (Blechschmidt et al., 2016). A first observational evidence of a large IO plume emitted from a volcanic eruption in Alaska was revealed (Schönhardt et al., 2017). A new retrieval algorithm of BrO (Seo et al., 2019) has been developed for the new TROPOMI onboard the S5P satellite. In addition, the first 24 years date record of tropospheric BrO over the Arctic was created and first analyses undertaken.
Role within (AC)³
Prof. Dr. John P. Burrows
University of Bremen
Institute of Environmental Physics
Prof. Dr. Astrid Bracher
Alfred-Wegener-Insitute Helmholtz Center for Polar and Marine Research (AWI)
Dr. Anne Blechschmidt
University of Bremen
Institute of Environmental Physics
Pradhan H. K., Völker C., Losa S. N., Bracher A., Nerger L. 2020: Global assimilation of ocean-color data of phytoplankton functional types: Impact of different datasets. Journal of Geophysical Research Oceans, 125, e2019JC015586, https://doi.org/10.1029/2019JC015586
Zeppenfeld, S., M. van Pinxteren, M. Hartmann, A. Bracher, F. Stratmann, and H. Herrmann, 2019: Glucose as a potential chemical marker for ice nucleating activity in Arctic seawater and melt pond samples, accepted for publication in Environmental Science & Technology
Álvarez, E., S. Thoms, A. Bracher, Y. Liu, and C. Völker, 2019: Prediction of photo-protective carotenoids at global scale, accepted by Global Biogeochemical Cycles, doi.org/10.1029/2018GB006101
Fernandez, R.P., A. Carmona-Balea, C.A. Cuevas, J.A. Barrera, D.E. Kinnison, J.-F. Lamarque, C. Blaszczak-Boxe, K. Kim, W. Choi, T. Hay, A.-M. Blechschmidt, A. Schönhardt, J.P. Burrows, and A. Saiz-Lopez, 2019: Modeling the Sources and Chemistry of Polar Tropospheric Halogens (Cl, Br, I) using the CAM-Chem Global Chemistry-Climate Model, accepted for publication in J. Adv. Model Earth Sy., doi:10.1029/2019MS001655
Seo, S., A. Richter, A.-M. Blechschmidt, I. Bougoudis, and J.P. Burrows, 2019: First high resolution BrO column retrievals from TROPOMI, Atmos. Meas. Tech., 12, 2913-2932, doi:10.5194/amt-12-2913-2019
Soppa, M.A., V. Pefanis, S. Hellmann, S.N. Losa, J. Hölemann, M.A. Janout, F. Martynov, B. Heim, T. Dinter, V. Rozanov, and A. Bracher, 2019: Assessing the Influence of Water Constituents on the Radiative Heating of Laptev Sea Shelf Waters, Frontiers in Marine Science, 6, Article 221, doi:10.3389/fmars.2019.00221
Oelker, J., A. Richter, T. Dinter, V.V. Rozanov, J.P. Burrows, and A. Bracher, 2019: Global diffuse attenuation coefficient derived from vibrational Raman scattering detected in hyperspectral backscattered satellite spectra, Optics Express, 27, 2, A829-A855, doi:10.1364/OE.27.00A829
Engel A., A. Bracher, T. Dinter, S. Endres, J. Grosse, K. Metfies, I. Peeken, J. Piontek, I. Salter, E.-M. Nöthig, 2019: Inter-annual variability of organic carbon concentrations across the Fram Strait (Arctic Ocean) during summer 2009 -2017, Frontiers in Marine Science. section Global Change and the Future Ocean, 6, 187, doi:10.3389/fmars.2019.00187
Liu, Y., E. Boss, A.P. Chase, H. Xi, X. Zhang, R. Röttgers, Y. Pan, and A. Bracher, 2019: Retrieval of phytoplankton pigments and functional types from underway spectrophotometry in the Fram Strait, Remote Sensing, 11(3), 318, doi:10.3390/rs11030318
Liu. Y., Roettgers R., Ramírez-Pérez M., Dinter T., Steinmetz F., Noethig E.-M., Hellmann S., Wiegmann S., Bracher A., 2018: Underway spectrophotometry in the Fram Strait (European Arctic Ocean): a highly resolved chlorophyll a data source for complementing satellite ocean color, Optics Express, 26, 14, A678, doi:10.1364/OE.26.00A678.
Data supplement is available here.
Losa S., Soppa M. A., Dinter T., Wolanin A., Brewin R. J. W., Bricaud A., Oelker J., Peeken I., Gentili B., Rozanov. V. V., Bracher A., 2017: Synergistic exploitation of hyper- and multispectral precursor Sentinel measurements to determine Phytoplankton Functional Types at best spatial and temporal resolution (SynSenPFT), Front. Mar. Sci., 4:203, doi:10.3389/fmars.2017.00203
Data supplement is available here.
Rozanov V.V., T. Dinter, A.V. Rozanov, A. Wolanin, A. Bracher, Burrows J.P., 2017: Radiative transfer modeling through terrestrial atmosphere and ocean accounting for inelastic scattering processes: Software package SCIATRAN. J. Quant. Spectrosc. Rad. Transfer, 194, 65-85, doi:10.1016/j.jqsrt.2017.03.009
Space based observation of volcanic iodine monoxide, Atmos. Chem. Phys., 17, 4857-4870,2017:
Blechschmidt, A.-M., Richter, A.,Burrows, J. P., Kaleschke, L., Strong, K., Theys, N., Weber, M., Zhao, X., and Zien, A., 2016: An exemplary case of a bromine explosion event linked to cyclone development in the Arctic, Atmos. Chem. Phys.,16, 1773-1788, doi:10.5194/acp-16-1773-2016