Sunny slopes are slopes with their backs to the sun, while shady slopes are slopes with their backs to the sun. In the northern hemisphere, the sunshine in the area north of the Tropic of Cancer mainly shines from south to north, so the southern slope is sunny and the northern slope is cool. In the southern hemisphere, sunlight mainly shines from north to south in the area south of the Tropic of Capricorn, so the northern slope is sunny and the southern slope is cool.
First, sunny slopes and shady slopes
The sunny side is called "sunny slope" and the shady side is called "shady slope". In the northern hemisphere, the south of the mountain is sunny and the north of the mountain is cool. The slope facing south is sunny, and the slope facing north is shady. The southern hemisphere is the opposite.
Aspect is defined as the projection direction of the slope normal on the horizontal plane (which can also be popularly understood as the direction from high to low). Aspect plays an important role in mountain ecology. The orientation of mountains has an influence on sunshine hours and solar radiation intensity. For the northern hemisphere, the radiation income of the southern slope is the most, followed by the southeast and southwest slopes, then the east and west slopes, the northeast and northwest slopes, and the north slope is the least.
The vegetation on shady slope is more lush than that on sunny slope, which shows that the forest area on shady slope is much larger than that on sunny slope. The grassland area above and below the forest land is also that the shady slope is larger than the sunny slope, while the desert area is the opposite, and the sunny slope is larger than the shady slope. This is because the heat here is very rich, and the heat on the shady slope can also meet the needs of plant growth, while the sunshine on the sunny slope is stronger, the heat is more than that on the shady slope, and the water vapor is not easy to condense under high temperature conditions, so the precipitation on the shady slope is more than that on the sunny slope.
Second, the influence of slope direction on biology
1, the temperature or vegetation on sunny slopes (sunny or southern slopes) and backlit slopes (shady or northern slopes) are often quite different. The south or southwest slope is the warmest, the north or northeast slope is the coldest, and the extreme temperature difference at the same height is 3 ~ 4℃.
2. The influence of slope direction on precipitation is also obvious. Due to the separation of a mountain, the precipitation can be several times different. The warm and humid airflow from the southwest forms a large amount of precipitation on the west and southwest slopes of the north-south or north-south mountainous areas; The warm and humid airflow in the southeast caused abundant precipitation on the eastern and southeastern slopes.
3. Due to the comprehensive effects of light, temperature, rainfall, wind speed, soil texture and other factors, slope direction can affect plants, thus causing changes in the ecological relationship between plants and the environment.