Caitlin Semmens

Much of the world’s population now resides within cities where altered energy use, building distributions, transportation networks, and surface characteristics influence land-atmosphere interactions, energy and water budgets, and carbon cycles, relative to rural areas. Knowledge of the surface properties that affect exchanges of energy and mass, as...

Much of our understanding of land-atmosphere interactions is rooted in direct flux measurements by the eddy covariance (EC) method. The EC method of analyzing in-situ data from flux towers has become the standard tool for monitoring turbulent heat exchange, trace gas emissions, and the water balance over land surfaces, including cities. The EC meth...

Diurnal and seasonal changes of δ 13 C and δ 18 O in carbon dioxide measured by eddy covariance over an urban surface The isotopic composition of the greenhouse gas CO 2 can provide valuable information about its sources. For example , linear mixing models have been used to identify the sources of enhanced CO 2 in the urban atmosphere using urban a...

The isotopic composition (δ¹³C and δ18O) in atmospheric carbon dioxide (CO₂) originating from gasoline and diesel vehicle exhaust and from natural gas combustion was determined. Gasoline and diesel samples were taken in the exhaust of representative vehicles of the fleet in Vancouver, BC, Canada between November 2013 and May 2...