A numerical evaluation of global oceanic emissions of α-pinene and isoprene
A numerical evaluation of global oceanic emissions\n\nof -pinene and isoprene based on both “bottom-up”\n\nand “top-down” methods is presented. We infer that the\n\nglobal “bottom-up” oceanic emissions of -pinene and isoprene\n\nare 0.013 TgC yr−1 and 0.32 TgC yr−1, respectively.\n\nBy constraining global chemistry model simulations with the\n\nshipborne measurement of Organics over the Ocean Modifying\n\nParticles in both Hemispheres summer cruise, we\n\nderived the global “top-down” oceanic -pinene source of\n\n29.5 TgC yr−1 and isoprene source of 11.6 TgC yr−1. Both\n\nthe “bottom-up” and “top-down” values are subject to large\n\nuncertainties. The incomplete understanding of the in-situ\n\nphytoplankton communities and their range of emission potentials\n\nsignificantly impact the estimated global “bottomup”\n\noceanic emissions, while the estimated total amounts\n\nof the global “top-down” oceanic sources can be influenced\n\nby emission parameterizations, model and input data spatial\n\nresolutions, boundary layer mixing processes, and the treatments\n\nof chemical reactions. The global oceanic -pinene\n\nsource and its impact on organic aerosol formation is significant\n\nbased on “top-down” method, but is negligible based on\n\n“bottom-up” approach. Our research highlights the importance\n\nof carrying out further research (especially measurements)\n\nto resolve the large offset in the derived oceanic organic\n\nemission based on two different approaches.