Can simple models predict large-scale surface ocean isoprene concentrations?
Dennis Booge1,Christa A. Marandino1,Cathleen Schlundt1,Paul I. Palmer2,Michael Schlundt1,Elliot L. Atlas3,Astrid Bracher4,5,Eric S. Saltzman6,and Douglas W. R. Wallace7Dennis Booge et al. Dennis Booge1,Christa A. Marandino1,Cathleen Schlundt1,Paul I. Palmer2,Michael Schlundt1,Elliot L. Atlas3,Astrid Bracher4,5,Eric S. Saltzman6,and Douglas W. R. Wallace7
1GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
2School of GeoSciences, University of Edinburgh, Edinburgh, UK
3Rosenstiel School of Marine and Atmospheric Science (RSMAS), University of Miami, Miami, FL, USA
4Alfred Wegener Institute – Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
5Institute of Environmental Physics, University Bremen, Bremen, Germany
6Department of Earth System Science, University of California, Irvine, CA, USA
7Department of Oceanography, Dalhousie University, Halifax, Canada
1GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
2School of GeoSciences, University of Edinburgh, Edinburgh, UK
3Rosenstiel School of Marine and Atmospheric Science (RSMAS), University of Miami, Miami, FL, USA
4Alfred Wegener Institute – Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
5Institute of Environmental Physics, University Bremen, Bremen, Germany
6Department of Earth System Science, University of California, Irvine, CA, USA
7Department of Oceanography, Dalhousie University, Halifax, Canada
Received: 02 Jun 2016 – Discussion started: 22 Jun 2016 – Revised: 26 Aug 2016 – Accepted: 05 Sep 2016 – Published: 22 Sep 2016
Abstract. We use isoprene and related field measurements from three different ocean data sets together with remotely sensed satellite data to model global marine isoprene emissions. We show that using monthly mean satellite-derived chl a concentrations to parameterize isoprene with a constant chl a normalized isoprene production rate underpredicts the measured oceanic isoprene concentration by a mean factor of 19 ± 12. Improving the model by using phytoplankton functional type dependent production values and by decreasing the bacterial degradation rate of isoprene in the water column results in only a slight underestimation (factor 1.7 ± 1.2). We calculate global isoprene emissions of 0.21 Tg C for 2014 using this improved model, which is twice the value calculated using the original model. Nonetheless, the sea-to-air fluxes have to be at least 1 order of magnitude higher to account for measured atmospheric isoprene mixing ratios. These findings suggest that there is at least one missing oceanic source of isoprene and, possibly, other unknown factors in the ocean or atmosphere influencing the atmospheric values. The discrepancy between calculated fluxes and atmospheric observations must be reconciled in order to fully understand the importance of marine-derived isoprene as a precursor to remote marine boundary layer particle formation.
Isoprene, a biogenic trace gas, is an important precursor of secondary organic aerosol/cloud condensation nuclei. Here, we use isoprene and related field measurements from three different ocean data sets together with remotely sensed satellite data to model global marine isoprene emissions. Our findings suggest that there is at least one missing oceanic source of isoprene and possibly other unknown factors in the ocean or atmosphere influencing the atmospheric values.
Isoprene, a biogenic trace gas, is an important precursor of secondary organic aerosol/cloud...
