| Autor: |
Wells KC; Department of Soil, Water, and Climate, University of Minnesota, St Paul, MN, USA., Millet DB; Department of Soil, Water, and Climate, University of Minnesota, St Paul, MN, USA. dbm@umn.edu., Payne VH; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA., Deventer MJ; Department of Soil, Water, and Climate, University of Minnesota, St Paul, MN, USA.; Bioclimatology, University of Göttingen, Göttingen, Germany., Bates KH; School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA., de Gouw JA; Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.; Department of Chemistry, University of Colorado, Boulder, CO, USA., Graus M; Department of Atmospheric and Cryogenic Sciences, University of Innsbruck, Innsbruck, Austria., Warneke C; Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.; NOAA Chemical Sciences Laboratory, Boulder, CO, USA., Wisthaler A; Institute for Ion Physics and Applied Physics, University of Innsbruck, Innsbruck, Austria.; Department of Chemistry, University of Oslo, Oslo, Norway., Fuentes JD; Department of Meteorology and Atmospheric Science, The Pennsylvania State University, University Park, PA, USA. |
| Abstrakt: |
Isoprene is the dominant non-methane organic compound emitted to the atmosphere 1-3 . It drives ozone and aerosol production, modulates atmospheric oxidation and interacts with the global nitrogen cycle 4-8 . Isoprene emissions are highly uncertain 1,9 , as is the nonlinear chemistry coupling isoprene and the hydroxyl radical, OH-its primary sink 10-13 . Here we present global isoprene measurements taken from space using the Cross-track Infrared Sounder. Together with observations of formaldehyde, an isoprene oxidation product, these measurements provide constraints on isoprene emissions and atmospheric oxidation. We find that the isoprene-formaldehyde relationships measured from space are broadly consistent with the current understanding of isoprene-OH chemistry, with no indication of missing OH recycling at low nitrogen oxide concentrations. We analyse these datasets over four global isoprene hotspots in relation to model predictions, and present a quantification of isoprene emissions based directly on satellite measurements of isoprene itself. A major discrepancy emerges over Amazonia, where current underestimates of natural nitrogen oxide emissions bias modelled OH and hence isoprene. Over southern Africa, we find that a prominent isoprene hotspot is missing from bottom-up predictions. A multi-year analysis sheds light on interannual isoprene variability, and suggests the influence of the El Niño/Southern Oscillation. |
Full text from SpringerLink