Thursday, November 18, 2010, 4:30PM - 5:30PM
Full title: "The effects of a climate manipulation experiment on snow properties and snow surface energy balance, Niwot Ridge, Colorado."
It is widely accepted that global warming is occurring as a result of increasing greenhouse gases (IPPC, 2007). Changes in climatic variables alter snow properties such as snow depth, snow grain morphology, stratigraphy, and density. These characteristics play an important role in radiative fluxes through the snowpack. Understanding the energy budget of the snow surface is essential to providing information on a number of processes, such as snowpack ripening, snow metamorphism, snowmelt production and runoff, and biochemical cycling.
The consequences of a changing climate has created a desire among scientists to develop a methodology to simulate global warming in order to study the effects it may have on hydrological, ecological, and biological systems. A global warming experiment that uses infrared heaters to warm plots has been implemented on Niwot Ridge, Colorado since 2008, at three sites along an elevational gradient. An important aspect in interpreting these experiments, as well as developing a better understanding of interactions between climate, hydrology, and ecological processes is how the snowpack responds to radiative forcing caused by IR climate manipulation experiments.
Preliminary results from the 2009-2010 winter season illustrate significant differences in snowpack formation and snow properties between heated and control plots, as well as between all three sites. At the lower subalpine site, heated plots became snowfree 24-48hrs after every storm. At the upper subalpine site, melt occurred a week earlier in the heated plots, and the entire site became snowfree by June 11. On the contrary, the alpine site did not become snowfree until June 19, and heated plots varied in melt out date from 0-5 days earlier than control plots. Part of the explanation lies in the thermal regime of the snow. The formation of caves in the alpine and subalpine sites due to the uneven distribution of energy from the heaters altered the flow of heat causing different snowmelt characteristics.