Ground temperature and climate change

Three studies are presented dealing with the relationship between ground temperatures, surface meteorological parameters, and different vegetation cover. These observations are related to borehole temperature profiles and the record they provide of climate change at the decadal to centennial time scale.;The first study examines how borehole temperatures respond to surface temperature changes using three boreholes in northwestern Utah that have been repeatedly logged for temperature over a period of 29 years. Systematic subsurface temperature changes of up to 0.6 °C are observed in the upper sections of these boreholes. Synthetic temperature profiles computed from surface data at nearby meteorological stations reproduce both the amplitude and pattern of the transient temperature observations, fitting observations to within 0.03 °C or better. This provides observational confirmation of the strong coupling between surface temperature change and borehole temperature transients.;The second study compares observations from a set of meteorological stations in the Cascades Mountains in Oregon that show vegetation cover can significantly affect ground temperatures due primarily to the influence of trees shading the ground from incoming solar radiation. During the period between 2000 and 2004, air temperature differences between the two sites decreased only slightly from 1.7 °C to 1.1 °C, while ground temperature differences were cut nearly in half from 2.8 °C to 1.5 °C. These changes are directly connected to the decrease in solar radiation over the study period as the forest grew back. Subsurface temperatures are reproducible using the Noah land surface model, but are largely influenced by incoming solar radiation.;The third section addresses the importance of public and educational outreach in the realm of climate change, which led to the development and publishing of meteorological and subsurface data from the Emigrant Pass Observatory located in the Grouse Creek Mountains in northwestern Utah through a website. The primary goals of this website are to provide a tutorial for understanding both local climate and climate change, and their relation to diffusion of temperatures into the Earth's subsurface, to facilitate access to available climate data, and to provide educational lesson ideas for using real data to understand local climate change.