Spatial variability in tropospheric peroxyacetyl nitrate in the tropics
from infrared satellite observations in 2005 and 2006
Vivienne H. Payne1, Emily V. Fischer2, John R. Worden1, Zhe Jiang3, Liye Zhu2, Thomas P. Kurosu1, and Susan S. Kulawik41Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, 91109, USA 2Colorado State University, Department of Atmospheric Science, Fort Collins, Colorado, USA 3National Center for Atmospheric Research, Boulder, Colorado, USA 4Bay Area Environmental Research Institute, Mountain View, California, USA
Received: 23 Nov 2016 – Accepted for review: 13 Dec 2016 – Discussion started: 22 Dec 2016
Abstract. Peroxyacetyl nitrate (PAN) plays a fundamental role in the global ozone budget and is the primary reservoir of tropospheric reactive nitrogen over much of the globe. However, large uncertainties exist in how surface emissions, transport and lightning affect the global distribution, particularly in the tropics. We present new satellite observations of free tropospheric PAN in the tropics from the Aura Tropospheric Emission Spectrometer. This dataset allows us to test expected spatio-temporal distributions that have been predicted by models but previously not well observed. We compare here with the GEOS-Chem model with updates specifically for PAN. We observe an austral springtime maximum over the tropical Atlantic, a feature that model predictions attribute primarily to lightning. Over Northern Central Africa in December, observations show strong inter-annual variability, despite low variation in fire emissions, that we attribute to the combined effects of changes in biogenic emissions and lightning. We observe small enhancements in free tropospheric PAN corresponding to the extreme burning event over Indonesia associated with the 2006 El Nino.
Payne, V. H., Fischer, E. V., Worden, J. R., Jiang, Z., Zhu, L., Kurosu, T. P., and Kulawik, S. S.: Spatial variability in tropospheric peroxyacetyl nitrate in the tropics
from infrared satellite observations in 2005 and 2006, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2016-1047, in review, 2016.