A finite difference model for one-dimensional heat how with phase change was used to investigate the effect of climatic factors on thermal processes of the active layer and permafrost at Barrow, Alaska. Results show that the effective depth hear fraction of the seasonal snow cover ranged from 0.11 through 0.35, with an average of 0.18 +/- 0.08. The thickness of the depth hear layer varied from 2.7 cm to 4.8 cm, with an average value of 3.7 +/- 0.7 cm, The calculated mean annual ground and permafrost surface temperatures were about 0.7 degrees C higher than the measured values. The calculated active layer thicknesses were less than 10% greater than the measured values. Results from sensitivity analysis indicate that among the variable climate factors, air temperature is the most important single factor controlling the soil temperatures, while seasonal snow cover and soil moisture are also important but secondary factors. The existence of thin depth hear layer within the seasonal snow cover is crucial to its insulating effect, while snow thickness becomes a secondary factor. Thawing index and soil moisture conditions are the most important factors influencing active layer thawing processes. Freezing index and seasonal snow cover influence the development of the active layer but their effects are very limited. (C) 1998 John Wiley & Sons, Ltd.
