Mountain Climate - Mountain Geography: Physical and Human Dimensions - page 91

mountains is largely a response to solar radiation. The free air, however, essentially does
not respond to the heating effects of the sun, particularly at higher altitudes. A moun-
tain becomes heated at the surface but there is a rapid temperature gradient in the
surrounding air. Consequently, only a thin boundary layer or thermal shell surrounds
the mountain, its exact thickness depending on a variety of factors (e.g., solar intensity,
mountain mass, humidity, wind velocity, surface conditions, and topographic setting).
FIGURE 3.11 Cross section of an enclosed basin, Gstettneralm, in the Austrian Alps, showing a tem-
perature inversion in early spring. Elevation of valley bottom is 1,270 m (4,165 ft). Note increase
in temperature (°C) with elevation above valley floor, especially the rapid rise directly above the
pass. This results from the colder air flowing into a lower valley at this point. (After Schmidt 1934:
347.)
FIGURE 3.12 Diurnal temperature range at different elevations on Mount Fuji, Japan. The difference
between high and low altitudes is much more exaggerated in winter (left) than in summer (right).
(After Yoshino 1975: 193.)