关键词:

Abstract: Based on the field observations in various localities, some microclimatic features of undulating terrain are analysed. The main results are as follows: 1) It is just as pointed out by A. Woeikof that convex areas have a moderate climate while convex areas have an extreme one. The daily fluctuation of air tempera-tune and humidity is largest at the bottom of the valley smaller on the slop and smallesten the top of hill.2) The distribution of maximum and minimum temperature along the valley slope is shown as Fig.4, curve 1 represents temperature during clear weather with wind-speeds (v) at a height of 1.5 m above the ground less than 4 m per sec.;2-during clear weather, v-3.5 m/s; 3-during clear weather, v>5 m/s; 4-during cloudy weather, v＜1m/s; 5-during over-cast weather, v=1.5 m/s. 3) In middle latitudes, the daytime temperature on a hill is highest on the south slope, lowest on the north slope. (Fig. l) 4) On a hill the isotherms in nighttime are generally parallel to the contours of the ground. The temperature becomes lower and lower as approaching to the foot of the hill (Fig. 2). 5) Fig. 7 shows the distribution of wind speed around a peak. The maximum of speed occurs at the top while minimum at the foot behind the peak. There are two secondary maxima near the middle of both slopes parallel to the wind direction and a secondary minimum at the foot of the windward slope. 6) In an undulating country the distribution of precipitation recerved by the rain-gauge is just contrary to that of wind. Wherever the wind is stronger, the precipitation is lesser, and vice versa. (Fig. 8) 7) Precipitation actually received by ground surface of a peak is largest in the lower part of its windward and beward slope and smallest at its top. Near the middle of the both sides parallel to wind, are also localities with much smaller precipitation.