Graduate Opportunities

What initiates intense precipitation events?  Is there some characteristic physics, biology and/or chemistry in cloud droplets that triggers intense precipitation?  Students study the organic and inorganic characteristics of aerosols and precipitation to find out.  They combine information on the origin of the moisture source for precipitation with sea surface temperatures and precipitation monitoring to help provide insights into why, when and where intense precipitation might occur. 

Shipboard sampling programs offer the opportunity for sea-minded students to get their hands wet.  How do gases released from the ocean contribute to cloud properties?  What is their relationship to aerosols and are aerosols an important feedback mechanism to global climate change?  This study involves using atmospheric sulfur compounds that are found over the Pacific, Atlantic and Arctic oceans and examining their isotope composition to understand how much aerosol is present from natural and human-related emissions. and their interaction in marine air.  This program is part of a large international study called SOLAS (Surface Ocean Lower Atmosphere Study) that will ultimately examine aspects of the CLAW hypothesis (see paragraph below) which postulates a negative climate feedback control via the atmospheric emissions from marine organisms.

Aerosols in the high arctic follow a seasonal pattern with low concentrations in summer and very high concentrations in early spring just before the polar sunrise.  Higher pollutant loads in winter, called Arctic Haze, are due to the transport of pollutants from lower latitudes. Aerosols from spring and summer months are less influenced by pollutant sources and contain a wealth of information about the formation of dimethylsulfide (DMS), a gas released to the atmosphere as microorganisms in the surface of the ocean decay.  James Lovelock proposed a theory about how the formation, release and oxidation of DMS acted as a natural regulatory mechanism to maintain surface temperatures on the Earth favourable to life, through the formation of aerosol sulfate from DMS oxidation. This "CLAW Hypothesis" is difficult to verify because DMS concentrations are highly variable in space and time and measurements typically must be made very shortly after taking a water (or air sample). However, if sulfur isotopes in aerosols are used, then it is possible to find the proportion of DMS sulfate. This project looks at changes in DMS sulfate in Arctic aerosols on annual to decadal periods and the difference in DMS sulfate at two Arctic measurement sites.

If you like working in the field and with a wide variety of instrumentation, this project is ideal. The student who takes on this project will set up computer controlled air quality monitoring systems and will help calibrate and operate the systems in several field campaigns.  This is an exciting opportunity to learn and/or use multiple air quality measurement systems, dataloggers, and air pollutant characterization.  Field measurements for this program will potentially be performed in Alberta and BC.