How much do terrain effects impact the IHFC borehole paleoclimate data set?

Comparison of measured T-z profiles in the IHFC borehole-climate database with synthetic T-z profiles generated from the NCDC Climate Division annual data reveals some good agreement and some problems in linking the ground surface temperature (GST) with the surface air temperature (SAT). The change from the long-term annual mean temperature occurred several decades prior to the beginning of the instrumental record. The magnitude of change, warming or cooling, recorded in borehole data is greater than predicted by the meteorological data. Although the ensemble approach to analysis of the borehole data set has been generally accepted, this analysis indicates that the data could be greatly improved by consideration of terrain effects on the ground surface temperature. In this case, terrain effect implies all possible noise signals in the near surface thermal regime, e.g., topography, groundwater, deforestation, and urbanization. This research is supported by NSF ATM-038384