HR: 1400h
AN: A43A-11    [Abstracts]
TI: PBL Aerosols SE of Mexico City in the dry Season: Biomass Burning and Windblown Dust and its Impact on Photolysis Frequencies
AU: Junkermann, W
EM: wolfgang.junkermann@imk.fzk.de
AF: Institute of Meteorology and Climate Research, Atmospheric Environmental Division, Forschungszentrum Karlsruhe, Kreuzeckbahnstr. 19, Garmisch-artenkirch, 82467, Germany
AU: Grutter, M
EM: grutter@servidor.unam.mx
AF: Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México (UNAM), Circuito Exterior Ciudad Universitaria, Mexico City, DF 04510, Mexico
AU: Baumgardner, D
EM: darrel@servidor.unam.mx
AF: Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México (UNAM), Circuito Exterior Ciudad Universitaria, Mexico City, DF 04510, Mexico
AU: * Steinbrecher, R
EM: rainer.steinbrecher@imk.fzk.de
AF: Institute of Meteorology and Climate Research, Atmospheric Environmental Division, Forschungszentrum Karlsruhe, Kreuzeckbahnstr. 19, Garmisch-artenkirch, 82467, Germany
AB: During the dry season in March 2006 airborne investigations on aerosol distributions, ultraviolet actinic radiation and ozone profiles were performed southeast of Mexico City using an ultralight aircraft as a mobile platform. The area investigated covered the rural area southeast of Mexico City, the Chalco Valley, Huexca and Atlixco south of the volcano Popocatepetl, east of Paso de Cortés to the airport of Puebla and the pass between Puebla and Mexico City north of the volcano Ixtachiuatl. The Chalco valley is the main venting valley of the Mexico City basin to the south. Intense biomass burning was observed on both slopes of the volcanoes leading to strong pyrocumulus cloud production in the northern part of the national reserve and above the motorway Puebla-Mexico. Fine particle (> 10 nm) numbers reached up to 80000/cm³ close to the burning plumes with significant reduction to ~ 30-40000/cm³ in the Chalco valley where coarse particles (> 300 nm) dominated the total mass. Dust devils transporting coarse soil particles up to elevations of more than 4000 m a.s.l. were frequently observed. Particles and air masses of pollution sources in the area can be characterized by aerosol size distributions and/or spectral absorption from multi-wavelength aethalometer measurements as well as from ozone mixing ratios and meteorological data measured onboard. The aerosol impact on photolysis rates and air chemistry is derived from vertical profiles of actinic radiation in the JO¹D and JNO₂ spectral regimes at 300 nm and 380 nm, respectively. Profiles were flown on both sides of the volcano ridge, south of Popocatepetl and above Tenango del Aire where aircraft measurements were supported by ceilometer aerosol vertical profiles.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0478 Pollution: urban, regional and global (0345, 4251)
DE: 0490 Trace gases
SC: Atmospheric Sciences [A]
MN: 2007 Joint Assembly