Simulations of Meteorological Variations over Arctic Coastal Tundra under Various Physical Interface Conditions

Meteorological properties of the tundra are treated within the context of a general ecosystem model. The biosphere is placed in the role of an active interface within a stack of horizontally uniform physical layers under the influence of incident solar radiation, the demonstrably dominant exogenous state variable. Diurnal variation of the thermodynamic states of these physical layers is calculated as the solution of differential equations governing the diffusion of heat and moisture. The results of numerical experiments on dry ground regions demonstrate that atmospheric moisture and temperature, during the biotically active summertime, are influenced by the meteorological history of the immediately preceding summertime level of the permafrost boundary. They are influenced to a degree that is at least comparable to the effect of daily fluctuations in cloud cover and prevailing winds. Numerical experiments on tundra shallow lakes imply a strong influence by the region's heterogeneity on near-surface air temperatures.