Areas of interest: Snow hydrology; Carbon budget, Niwot LTER
Faculty Advisor: Peter Blanken
Thesis
2009 - Meteorological Controls on the Seasonal Exchange of Water and Carbon Dioxide from High-Elevation Alpine Tundra at Niwot Ridge, Colorado
2015 - Spacio-temporal patterns of soil respiration and the age of respired carbon from high-elevataion alpine tundra.
Research Interests
My principal research aims to constrain the water and carbon cycle of alpine tundra at Niwot Ridge, Colorado. Alpine ecosystems are vital to resource management and may be especially sensitive climate change indicators, but inherently remote and rugged terrain makes these areas traditionally difficult to research. To better understand the biological underpinnings of this system, I have implemented a multi-scale approach designed to capture both the plot-scale variability and whole-ecosystem magnitude of carbon and water fluxes to the atmosphere. My research also considers the meteorological drivers, overarching cause, and potential impacts of an observed carbon cycle imbalance through the use of modeling and radiocarbon dating techniques.
Selected Publications
Burns SP, Molotch NP, Williams MW, Knowles JF, Seok B, Monson RK, Turnsipseed AA, Blanken PD. (2014).Snow temperature changes within a seasonal snowpack and their relationship to turbulent fluxes of sensible and latent heat. Journal of Hydrometeorology 15: 117-142.
Knowles JF, Burns SP, Blanken PD, Monson RK. (2014). Fluxes of energy, water, and carbon dioxide from mountain ecosystems at Niwot Ridge, Colorado. Plant Ecology & Diversity.doi:10.1080/17550874.2014.904950
Knowles JF, Blanken PD, Williams MW, Chowanski KM. (2012). Energy and surface moisture seasonally limit evaporation and sublimation from snow-free alpine tundra. Agricultural and Forest Meteorology 157: 106-115.
Blanken PD, Williams MW, Burns SP, Monson RK, Knowles J, Chowanski K, Ackerman T . (2009). A comparison of water and carbon dioxide exchange at a windy alpine tundra and subalpine forest site near Niwot Ridge, Colorado. Biogeochemistry 95(1): 61-76.
Publications updated May 2014