Export of NO y from the North American Boundary Layer: Reconciling Aircraft Observations and Global Model Budgets

• Main Authors: Qinbin Li, Daniel J. Jacob, J. William Munger, Robert M. Yantosca, David D. Parrish
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.362.2115; http://acmg.seas.harvard.edu/publications/li2004a.pdf

[1] Fossil fuel combustion accounts for>50 % of the global atmospheric emission of NOx, but this source is concentrated in the polluted continental boundary layer (CBL) and only a small fraction is exported as NOy (NOx and its oxidation products) to the global troposphere. Better quantification of this export efficiency is needed because of its implications for global tropospheric ozone. A recent Lagrangian analysis of the NOy-CO correlations observed from the North Atlantic Regional Experiment in September 1997 (NARE’97) aircraft campaign downwind of eastern North America (September 1997) indicated a NOy export efficiency of <10%, with <10 % of the exported NOy present as NOx. In contrast, previous three-dimensional (3-D) model Eulerian budget analyses for the North American boundary layer indicated NOy export efficiencies of 25–30%, with 30– 35 % of the exported NOy present as NOx. We investigated this apparent discrepancy by simulating the NARE’97 aircraft observations with a global 3-D model of tropospheric chemistry (GEOS-CHEM) and using the model to calculate the NOy export efficiency both through a Lagrangian analysis of the NOy-CO correlations along the aircraft flight tracks and through an Eulerian budget analysis for the North American boundary layer. The model reproduces the variability and NOy-CO correlations observed in the aircraft