Field Studies: Aircraft and Ground-based

 

Aircraft Observations

Interested students will work with scientists at nearby NASA Ames Research Center in Mountain View. The current topic of interest is Intercontinental Transport of Air Pollution. INTEX field programs aim to understand the transport and transformation of gases and aerosols on transcontinental/intercontinental scales and assess their impact on air quality and climate. Dr. Hanwant Singh and Dr. Philip Russell are the primary contacts for possible NASA/Stanford field project participation.

 

 

Ground-Based Measurements

We setup ground-based filter collectors at various locations to collect bulk samples of atmospheric aerosols. We use these samples to determine the chemical composition of particles using a wide variety of analytical techniques. We also use the laboratory experiments highlighted above to measures the physicochemical properties of aqueous solution extracts obtained from the filter samples. We plan to compare and contrast the physico-chemical properties of major aerosol types in the atmosphere (i.e., urban, biomass buring, biogenic, soil dust and sea-salt) and how human emissions may influence such properties. This project will involve collaborations with Adina Paytan in the Department of Geological and Environmental Sciences.

 

 

Relevant References

Tabazadeh, A., R. J. Yokelson, H. B. Singh, P. V. Hobbs, J. H. Crawford, and L. T. Iraci, Heterogeneous chemistry involving methanol in tropospheric clouds, Geophys. Res. Lett., 31, L06114, doi: 10.129/2003GL018775, 2004. (AGU issued a press release on this article)

Singh, H. B., A. Tabazadeh, M. J. Evans, B. D. Field, D. J. Jacob, G. Sachse, J. H. Crawford, R. Shetter, and W. H. Brune, Oxygenated volatile organic chemicals in the oceans: Inferences and implications based on atmospheric observations and air-sea exchange models, Geophys. Res. Lett., 30(16), 1862, doi:10.1029/2003GL017933, 2003.

Singh, H. B., B. Anderson, M. Avery, W. Viezee1, Y. Chen, A. Tabazadeh, P. Hamill, R. Pueschel1, H. E. Fuelberg, and J. R. Hannan, Global distribution and sources of volatile and nonvolatile aerosol in the remote troposphere, 107(D11), 10.1029/2001JD000486, 2002.

Toon, O. B., A. Tabazadeh, E. V. Browell, and J. Jordan, The properties of Arctic polar stratospheric clouds during January, 1989, J. Geophys. Res., 105, 20,589, 2000.

Singh, et al., Distribution and fate of select oxygenated organic species in the troposphere and lower stratosphere over the Atlantic, J. Geophys. Res., 105, 3795, 2000.

Tabazadeh, A., M. Z. Jacobson,  H. B. Singh, O. B. Toon,  J. S. Lin, R. B. Chatfield, A. N. Thakur, R. W. Talbot, and J. E. Dibb, Nitric acid scavenging by mineral and biomass burning aerosols, Geophys. Res. Lett., 25, 4185, 1998.

Jensen, E. J., O. B. Toon, A. Tabazadeh, et al., Ice nucleation processes in upper tropospheric wave-clouds observed during SUCCESS, Geophys. Res. Lett. 25, 1367, 1998.

Del Negro, L. A., et al., Evaluating the role of NAT, NAD, and liquid H2SO4/H2O/HNO3 solutions in Antarctic polar stratospheric cloud aerosol: Observations and implications, J. Geophys. Res., 102, 13,255, 1997.

Tabazadeh, A., and O. B. Toon, The presence of metastable HNO3/H2O solid phases in the stratosphere inferred from ER-2 data. J. Geophys. Res., 101, 9071, 1996.

 Tabazadeh, A., O. B. Toon, B. L. Gary, J. T. Bacmeister, and M. R. Schoeberl, Observational constraints on the formation of Type 1 polar stratospheric clouds, Geophys. Res. Lett., 23, 2109, 1996.