Welcome to the research group of Dr. Jeff Pierce at Colorado State University in Ft. Collins, Colorado, USA and Dalhousie University in Halifax, NS, Canada.

Our research focuses on atmospheric aerosols and their interactions with clouds and climate. Changes in atmospheric aerosols (airborne particles) due to human-generated pollution affects the earth's climate by interacting with the sun and earth's radiation and by modifying clouds. The extent to which this increased aerosol concentration has affected climate is generally regarded to be one of the most uncertain gaps in our understanding of recent climate change. Aerosols also affect human health and decrease visibility, so it is important to understand the processes that control aerosol concentrations in the atmosphere in order to protect quality of life.

Specific areas of interest include:

(1) Aerosol-cloud interactions: Cloud droplets form on existing particles in the atmosphere; therefore, changes in aerosol concentrations affect many aspects of clouds, including their interaction with sunlight. Conversely, clouds affect the number and composition of aerosol particles in the atmosphere by removing particles during rain and by aqueous chemistry. Poor representations of these processes in atmospheric models lead to errors in aerosol predictions.
(2) Near source aerosol physics: The size and number of atmospheric particles may be greatly influenced by processes near their sources, such as in power plant plumes; however, these processes are currently ignored or are only crudely accounted for in regional and global atmospheric models.
(3) New particle formation: A large portion of the number of atmospheric particles were formed from gases in the atmosphere (rather than being emitted from a source). The rate at which these particle formation events occur is very uncertain, yet must be better understood in order to reduce uncertainties in the climate effects of aerosols.

Credit Jeff Schmaltz, MODIS Rapid Response Team, NASA/GSFC
This is a true-color photo from the MODIS instrument on NASA's Terra satellite of the Pacific Ocean off of the coast of North America. The white streaks in the thinner cloud portions are where aerosols from ship emissions have changed the cloud properties, making them brighter. These interactions have a large impact on climate!

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