Document: PAU-3-65-6

Topoclimatic models for complex terrain in the Rocky Mountains of Colorado.

FU, P.* and P.RICH

University of Kansas, Lawrence, KS 66044 USA ¹

Abstract:
Spatial and temporal patterns of microclimate in mountainous regions can be predicted based on mechanistic understanding of interactions between climatic factors and topography. In turn, microclimate is a major determinant of habitat quality for vegetation. The goal of this study was to model the spatial patterns of air temperature, soil temperature, and soil moisture as they are influenced by variation in incoming solar radiation (insolation) at a landscape scale. The study was conducted in the vicinity of Rocky Mountain Biological Laboratory (RMBL), Colorado, and utilized a USGS digital elevation model (DEM) and measurements from four weather stations. We calculated maps of insolation during the growing season using a geometric model (TopoView/Solar Analyst) that using the DEM for input. Resultant global insolation was corrected using "percent sunshine", which accounts for the local effects of clouds (mean absolute error < 2%). Hourly air temperature was predicted using a modified lapse rate model, which accounted for deviation from a simple lapse rate based on insolation (r = 0.85 between residual and insolation). Minimum daily soil temperature was predicted from a simple lapse rate model (r = -0.89 at 12 cm and r = -0.71 at 25 cm between minimum temperature and elevation). Daily increase in soil temperature increase (max-min) was strongly correlated with daily insolation (r = 0.96 at 12 cm and r = 0.91 at 25 cm). Soil moisture was derived using flow accumulation, curvature, and slope, and then rescaled based on observed values. Vegetation patterns correspond well with topoclimatic predictions.

Keywords: GIS, insolation, microclimate, montane ecosystems, topoclimatic models, vegetation

This abstract is being presented at: 10:30 AM in session:
Poster Session #5: Landscape Ecology.