Analysis of ozone and nitric acid in spring and summer Arctic pollution using aircraft, ground-based, satellite observations and MOZART-4 model: source attribution and partitioningReport as inadecuate




Analysis of ozone and nitric acid in spring and summer Arctic pollution using aircraft, ground-based, satellite observations and MOZART-4 model: source attribution and partitioning - Download this document for free, or read online. Document in PDF available to download.

1 NCAR - National Center for Atmospheric Research Boulder 2 Spectroscopie de l-atmosphère, Service de Chimie Quantique et Photophysique 3 TACT - LATMOS LATMOS - Laboratoire Atmosphères, Milieux, Observations Spatiales 4 Department of Physics Toronto 5 ESRL - NOAA Earth System Research Laboratory 6 CIRES - Cooperative Institute for Research in Environmental Sciences 7 CALTECH - California Institute of Technology

Abstract : In this paper, we analyze tropospheric O3 together with HNO3 during the POLARCAT Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols, and Transport program, combining observations and model results. Aircraft observations from the NASA ARCTAS Arctic Research of the Composition of the Troposphere from Aircraft and Satellites and NOAA ARCPAC Aerosol, Radiation and Cloud Processes affecting Arctic Climate campaigns during spring and summer of 2008 are used together with the Model for Ozone and Related Chemical Tracers, version 4 MOZART-4 to assist in the interpretation of the observations in terms of the source attribution and transport of O3 and HNO3 into the Arctic north of 60° N. The MOZART-4 simulations reproduce the aircraft observations generally well within 15%, but some discrepancies in the model are identified and discussed. The observed correlation of O3 with HNO3 is exploited to evaluate the MOZART-4 model performance for different air mass types fresh plumes, free troposphere and stratospheric-contaminated air masses. Based on model simulations of O3 and HNO3 tagged by source type and region, we find that the anthropogenic pollution from the Northern Hemisphere is the dominant source of O3 and HNO3 in the Arctic at pressures greater than 400 hPa, and that the stratospheric influence is the principal contribution at pressures less 400 hPa. During the summer, intense Russian fire emissions contribute some amount to the tropospheric columns of both gases over the American sector of the Arctic. North American fire emissions California and Canada also show an important impact on tropospheric ozone in the Arctic boundary layer. Additional analysis of tropospheric O3 measurements from ground-based FTIR and from the IASI satellite sounder made at the Eureka Canada and Thule Greenland polar sites during POLARCAT has been performed using the tagged contributions. It demonstrates the capability of these instruments for observing pollution at northern high latitudes. Differences between contributions from the sources to the tropospheric columns as measured by FTIR and IASI are discussed in terms of vertical sensitivity associated with these instruments. The first analysis of O3 tropospheric columns observed by the IASI satellite instrument over the Arctic is also provided. Despite its limited vertical sensitivity in the lowermost atmospheric layers, we demonstrate that IASI is capable of detecting low-altitude pollution transported into the Arctic with some limitations.





Author: C. Wespes - L. Emmons - D. P. Edwards - J. Hannigan - Daniel Hurtmans - M. Saunois - Pierre-François Coheur - Cathy Clerbaux - M

Source: https://hal.archives-ouvertes.fr/



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