Almudena García-García

Master's candidate at StFX

Supervisors: Dr. Hugo Beltrami & Dr. Laxmi Sushama
Enrolled in CREATE program in September 2014

Relationship between surface air and deep soil temperature in the CMIP5 model simulations.

In order to fully understand the magnitude of the planetary energy imbalance, it is necessary to estimate the energy stored in all of it's subsystem components, including the continental energy contribution. Boreholes temperature data may be the only method that yields a direct measure of the ground heat storage. However, paleoclimatic reconstructions and estimates of the continental heat storage from borehole temperature data assume an existing link between surface air and deep soil temperatures. We examine the central assumption of borehole paleoclimatology - that is, the coupling between atmosphere and ground, within the Coupled Model Intercomparison Project 5 (CMIP5) model simulations. We evaluate the relationship between air and deep soil temperatures directly, as well as through approximating the temperature propagation as harmonic waves for each of the model simulations of the historical period and compare them to the North American Regional Reanalysis dataset. In addition, we studied the temporal evolution of air and ground coupling within the models, from the Historical and available Representative Concentration Pathways simulation experiments. Our preliminary results show that all models display stable coupling between air and ground, although there is significant variability in the level of coupling among models simulations as well as significant regional variability. Some of the variability is related to the effect of snow cover on the temporal evolution of the coupling, in the mid and high latitudes. However, the mean air and ground coupling for all models shows a long-term steady temporal relation between atmosphere and ground, supporting the inferences obtained from borehole climatology. After this study about the central assumption of borehole, we will continue evaluating the implications of the soil structure, within CMIP5 model simulations.