The wind force depends on the isobar diagram. The greater the pressure difference at the same distance (the denser the isobar), the greater the wind force. Wind speed. Wind power expressed by wind power level. The greater the wind, the stronger the wind level, and the graded wind has both magnitude and direction. Therefore, the wind forecast includes wind speed and direction. The magnitude of wind speed is often expressed by several winds. The level of wind is determined according to the degree of influence of wind on ground objects.
Method for judging wind direction
1, according to the sea level isobar distribution map.
If A is the center of high pressure and B is the center of low pressure, then ① northwest wind prevails and ② southwest wind prevails.
Distribution map of sea level isobar in the northern hemisphere
2, using cyclone and anticyclone diagram to judge.
For example:
Schematic diagram of cyclone in northern hemisphere
When judging the wind direction, pay attention to where the cyclone is. Generally, the south wind blows below the cyclone and the north wind blows above it; The west wind blows on the left side of the cyclone and the east wind blows on the right side of the cyclone.
3. Judging by the relationship between boiling point and air pressure.
For example, both m and n are 99.8℃, and the wind direction at point O is (b) when the sea level friction is ignored.
A. north wind b south wind c east wind d west wind
4. Judging by the characteristics of monsoon climate.
In China, northerly winds mainly blow in winter and southerly winds mainly blow in summer. South Asia blows northeast wind in winter and southwest wind in summer.
5. Judging by temperate maritime climate and Mediterranean climate.
Temperate maritime climate, the west wind blows all the year round, the southwest wind blows in the northern hemisphere and the northwest wind blows in the southern hemisphere. The climate of the Mediterranean is westerly in winter.