Vertical distribution of aerosols in the vicinity of Mexico City during MILAGRO-2006 Campaign P. A. Lewandowski1, W. E. Eichinger1, H. Holder2, J. Prueger3, J. Wang4, and L. I. Kleinman4 1IIHR-Hydroscience & Engineering University of Iowa, Iowa City, IA, USA 2Duke University, Rayleigh, NC, USA 3National Soil Tilth Laboratory, Ames, IA, USA 4Brookhaven National Laboratory, Upton, NY, USA
Abstract. On 7 March 2006, a mobile, ground-based, vertical pointing, elastic lidar
system made a North-South transect through the Mexico City basin. Column
averaged, aerosol size distribution (ASD) measurements were made on the
ground concurrently with the lidar measurements. The ASD ground measurements
allowed calculation of the column averaged mass extinction efficiency (MEE)
for the lidar system (1064 nm). The value of column averaged MEE was
combined with spatially resolved lidar extinction coefficients to produce
total aerosol mass concentration estimates with the resolution of the lidar
(1.5 m vertical spatial and 1 s temporal). Airborne ASD measurements
from DOE G-1 aircraft made later in the day on 7 March 2006, allowed the
evaluation of the assumptions of constant ASD with height and time used for
estimating the column averaged MEE.
The results showed that the aerosol loading within the basin is about twice
what is observed outside of the basin. The total aerosol base concentrations
observed in the basin are of the order of 200 μg/m3 and the base
levels outside are of the order of 100 μg/m3. The local heavy
traffic events can introduce aerosol levels near the ground as high as 900 μg/m3.
The article presents the methodology for estimating aerosol mass
concentration from mobile, ground-based lidar measurements in combination
with aerosol size distribution measurements. An uncertainty analysis of the
methodology is also presented.
Citation: Lewandowski, P. A., Eichinger, W. E., Holder, H., Prueger, J., Wang, J., and Kleinman, L. I.: Vertical distribution of aerosols in the vicinity of Mexico City during MILAGRO-2006 Campaign, Atmos. Chem. Phys., 10, 1017-1030, doi:10.5194/acp-10-1017-2010, 2010.