. Ecological investigations of the tundra biome in the Prudhoe Bay region, Alaska . by evaporation (sublimation) from the exposed soil and vegetation. The bare patches appear first on the south slopes of the dunes. Some of these were examined in detail during the afternoon of 19 April 1973. The south faces of exposed dirt had 5-8 cm of dry powdery soil on top of hard frozen ground. The north sides of these same patches had less than cm of dry powdery soil on top of the hard frozen soil. This indicates a significant difference in the amount of drying action produced by the sun and wind. The
. Ecological investigations of the tundra biome in the Prudhoe Bay region, Alaska . by evaporation (sublimation) from the exposed soil and vegetation. The bare patches appear first on the south slopes of the dunes. Some of these were examined in detail during the afternoon of 19 April 1973. The south faces of exposed dirt had 5-8 cm of dry powdery soil on top of hard frozen ground. The north sides of these same patches had less than cm of dry powdery soil on top of the hard frozen soil. This indicates a significant difference in the amount of drying action produced by the sun and wind. The temperature 2 cm below the soil surface on the south side was to °C; it was -11°C at the soil surface on the north side. The snow temperature was -16 to -17°C throughout its 20 cm depth at nearby places; the time of day was 1610 and 1700. A typical example of a small sand hill is shown in Fig. 14. The view is toward the north. Note the hoarfrost crystals growing on the adja- cent snow surface; these are formed downwind of the exposed bare patches. The crystals grow partly because water vapor, which enters the air over the bare patch, condenses as it moves downwind in air that cools as it passes over the snow surface. The crystals were generally on the south sides of dunes and they began immediate- ly downwind of exposed bare patches of ground. A good example of this is shown in Fig. 15, which looks west from the dune area toward the road near traverse T-1. The frost crystals appear on the south side but not on the north side of the dune, and a bare patch of soil was immedi- ately upwind of the frost crystal area. The snow
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Keywords: ., bookcentury1900, bookcollectionameri, bookcollectionbiodiversity
