The wind direction is the direction in which the wind is blowing.
The wind blowing from the north is north wind, and the wind blowing from south is south wind. First draw the horizontal pressure gradient force, and then draw the geostrophic deflection force according to the hemisphere. The geostrophic deflection force is perpendicular to the horizontal pressure gradient force. The northern hemisphere is to the right and the southern hemisphere is to the left. Points to the same. The wind direction is between the horizontal pressure gradient force and the geostrophic deflection force, and the angle is arbitrary.
How to judge wind direction
Geographical aspects
1. The horizontal pressure gradient force points from high pressure to low pressure, perpendicular to the isobars.
2. The wind direction is to the left in the southern hemisphere and to the right in the northern hemisphere.
3. The default for non-pointing beacons is "up, north, down, south, left, west, right, east". For pointed beacons, judge according to the pointing direction.
In terms of life
In which direction the red flag flies, or hold a thin silk scarf in your hand and hold it in the air. Watch where the silk scarf flies; or grab a handful of fine sand from the ground and sprinkle it into the air. You can know which direction the wind is blowing.
Wind direction measurement method
One of the instruments for measuring wind direction is the wind vane, which is generally 10-12 meters above the ground. If there are obstacles nearby, its height must be at least higher than the obstacles. The object should be 6 meters or above, and the short stick pointing north should be facing north. The direction in which the wind direction arrow points indicates the direction of the wind blowing at that time.
There is also a rectangular wind pressure plate on the wind detector (the heavy one weighs 800 grams, the light one weighs 200 grams). There is an arc-shaped frame next to the wind pressure plate, with long and short teeth on the frame. The number of long and short teeth that the wind pressure plate raises indicates the strength of the wind.