Remote sensing retrieval of isoprene concentrations in the Southern Ocean

• Published in: Geophysical Research Letters
• Main Authors: Rodríguez-Ros, Pablo, Gali Tapias, Martí, Cortés, Pau, Robinson, Charlotte Mary, Antoine, David, Wohl, Charel, Yang, MingXi, Simó, Rafel
• Other Authors: Barcelona Supercomputing Center
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2020
• Subjects: Àrees temàtiques de la UPC::Enginyeria agroalimentària::Ciències de la terra i de la vida; Ocean; Isoprene; Remote sensing; MODIS; Southern Ocean; Algorithm; Chlorophyll a; Mar; Antarctic; Canada; The Antarctic; Antarc*; Swiss Polar Institute
• Online Access: http://hdl.handle.net/2117/331405; https://doi.org/10.1029/2020GL087888

Isoprene produced by marine phytoplankton acts as a precursor of secondary organic aerosol and thereby affects cloud formation and brightness over the remote oceans. Yet the marine isoprene emission is poorly constrained, with discrepancies among estimates that reach 2 orders of magnitude. Here we present ISOREMS, the first satellite‐only based algorithm for the retrieval of isoprene concentration in the Southern Ocean. Sea surface concentrations from six cruises were matched with remotely sensed variables from MODIS Aqua, and isoprene was best predicted by multiple linear regression with chlorophyll a and sea surface temperature. Climatological (2002–2018) isoprene distributions computed with ISOREMS revealed high concentrations in coastal and near‐island waters, and within the 40–50°S latitudinal band. Isoprene seasonality paralleled phytoplankton productivity, with annual maxima in summer. The annual Southern Ocean emission of isoprene was estimated at 63 Gg C yr−1. The algorithm can provide spatially and temporally realistic inputs to atmospheric and climate models. This research was funded by the Spanish Ministry of Economy and Competitiveness through projects PEGASO (CTM2012‐37615) and BIOGAPS (CTM2016‐81008‐R) to R. S., and partially by the Australian Government through the Australian Research Council's Discovery Projects funding scheme (project DP160103387). The Antarctic Circumnavigation Expedition was made possible by funding from the Swiss Polar Institute and Ferring Pharmaceuticals. P. R. R. was supported by a “la Caixa” Foundation PhD Fellowship (2015–2019). Members of the ACE#1 research team are greatly acknowledged for providing data and technical support. We are grateful to NASA's Ocean Biology Processing Group (OBPG) for MODIS Aqua data and to the British Oceanographic Data Centre (BODC). We thank R. Wanninkhof (NOAA/AOML) and J. Trianes (Universidade de Santiago de Compostela) for providing the CCMP2 monthly climatology. P. R. R. would like to thank M. Babin, M. Levasseur, and M. Lizotte for hosting and training him at Takuvik Joint International Laboratory (Université Laval (Canada) CNRS (France)) during 2016. We also want to thank the Captain, officers, and crew of RV Hespérides and RV Akademik Tryoshnikov, engineers of the Marine Technology Unit (CSIC), and research colleagues for their support and help during the cruises. Peer Reviewed Postprint (published version)