Arab Weather - Weather experts and meteorologists monitor several indicators to determine the weather situation, such as temperatures, humidity, atmospheric pressure, precipitation, air masses and fronts. Wind speed and direction are important factors in forecasting the weather.
There are two types of wind; Vertical winds are not often felt near the surface of the earth, but we see their impact on the weather, such as the formation of clouds and causing atmospheric instability. There are horizontal winds, which we feel around us, so how is the direction of the wind determined? What is the benefit of knowing its direction?
The direction of the horizontal wind can be known in simple ways such as observing the movement of objects such as trees or flags, and there are several tools used to measure the direction of the wind, namely:
Wind vane : It is a simple tool consisting of a metal arm in the form of an arrow that rotates on an axis fixed at the top of a column, and underneath it are two rods on which the four directions are fixed.
Wind Sock Tool : This tool is widely used in airports to indicate to pilots the direction and intensity of the wind, so that the pilot can land against the direction of the wind. When it rises, the intensity of wind blows is greater, and if its height is simple, the wind is calm, and it rotates on a column to indicate the direction of the wind, so that the tail indicates the direction of the wind.
Forefinger method: The index finger can be used to determine the direction of the wind after getting wet and pointing it upwards. The side that the wind blows on the finger cools down as a result of the evaporation of moisture, so it is the direction from which the wind blows. However, using this method does not always give an accurate direction of the wind, especially in Wet or hot conditions.
The method of scattering dirt or grass : It is possible to take a handful of dirt or some grass and leave it to fall alone, so the place of its occurrence is the place from which the wind blows, and this method is often used by tennis or golf players and other sports that are affected by the direction and intensity of the wind.
The direction of the wind is determined by determining its source and the direction from which it is blowing, meaning that the wind that blows from north to south is called the north wind, and when the wind is northwest, for example, it is coming from the northwest towards the southeast.
There are three main forces that work together and control the movement of the wind, namely:
1. The force resulting from the gradient of atmospheric pressure values ( Pressure Gradient Force )
It is the force that results from different values of atmospheric pressure, and it is what pushes the air to move towards low pressure, and thus causes air to flow from high pressure towards low pressure.
2. Corilois Force
This force results from the Earth's rotation around itself, so that the Earth rotates counterclockwise, forcing the winds in the northern hemisphere to deflect to the right, and in the southern hemisphere to the left.
3. Frictional Force
The uneven surface of the earth and its rugged terrain leads to a change in wind speed, and also affects its direction, causing winds to diverge from heights and converge near low levels. elevations, causing air flow from the higher layers to replace it.
Wind patterns change from one place to another on the earth, and there is a prevailing direction in which the wind often blows in a place, which is called the Prevailing Winds , but the prevailing winds change from one region to another according to the location of the region and the season at that time.
Globally , winds move in certain patterns based on latitudes, due to the rotation of the Earth and differences in exposure to the sun. Winds move from west to east, and they are called Westerlies , and although the prevailing winds usually follow a general pattern, seasonal changes in wind direction can also occur. Changing wind patterns based on season is called monsoons.
Knowing the direction of the wind is important for several sectors, including the construction sector and the agricultural sector, and there are several benefits to knowing the direction of the local winds specific to a particular area, the following are ten benefits of knowing the direction of the wind:
1. It is important to know the direction of the wind when planning the construction of windbreaks to avoid the danger of strong winds or reduce the dust and dirt that they carry.
2. Knowing the direction of the wind helps direct the air flow inside the house or building and choose which windows to open.
3. Knowing the direction the wind is blowing helps avoid unwanted odors, smoke or polluted air.
4. It is important to know the prevailing winds when designing airports, and the direction of the winds is very important for pilots when taking off and landing an aircraft.
5. Knowing the direction of the wind benefits farmers greatly, especially when spraying agricultural crops, in order to avoid the transfer of materials to other crops, as well as the direction of the wind when irrigating crops, sowing seeds, or plowing and turning the soil.
6. Determining the direction of the wind helps meteorologists know the characteristics of the wind depending on the direction of its blow. The wind direction also helps in determining, tracking and predicting weather patterns, such as determining the direction of the movement of air depressions, and the transfer of precipitation from one region to another.
7. The direction of the wind affects the water in water bodies, such as the effect on the evaporation of surface water, its mixing, and the movement of hurricanes over it, and these processes have significant effects on the level and quality of water.
8. The wind has an effect on buildings and facilities, especially high-rise buildings, so determining the direction of the winds that usually blow over a particular area affects the architectural style in it.
9. Knowing the direction of the wind is important in marine navigation and for sailing boats.
10. In some sports, players check the direction of the wind in order to plan for a better performance in playing, such as golf, tennis, and others. The wind direction is also studied when performing marine sports activities such as surfing or aerial activities such as balloon riding.
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