Xiaohua's mother wants to know what the weather will be like tomorrow.
I. Explanation
Weather refers to the specific state of the atmosphere near the surface in a short period of time. Weather phenomenon refers to various natural phenomena in the atmosphere, that is, the comprehensive expression of the spatial distribution of various meteorological elements in the atmosphere (such as temperature, pressure, humidity, wind, clouds, fog, rain, flash, snow, frost, thunder, hail, haze, etc.). ) in an instant.
The weather process is the change process of weather phenomena with time in a certain area. All kinds of weather systems have certain time and space scales, and they are intertwined and influence each other.
The combination of many weather systems constitutes a large-scale weather situation and hemispheric and even global atmospheric circulation. The weather system is always in the process of rebirth, development and extinction, and there are corresponding weather phenomena in different development stages.
Second, the cause of the wind
The direct cause of the wind is the uneven distribution of air pressure in the horizontal direction. Wind is comprehensively influenced by different factors such as atmospheric circulation, topography and water area, and its manifestations are various, such as monsoon, local sea-land wind, valley wind and foehn wind. Simply put, wind is the directional movement of air molecules.
To understand the causes of wind, we must first understand two key concepts: air and air pressure. The components of air include nitrogen molecules (accounting for 78% of the total air volume), oxygen molecules (accounting for about 2 1%), water vapor and other trace components. All air molecules are moving at a very fast speed, colliding with each other and anything on the horizon.
Third, the causes of clouds
People are no strangers to clouds. White in sunny days and black in rainy days are called clouds. They make the sky unpredictable. People often see that the sky is sometimes blue and cloudless, sometimes white clouds are blooming, and sometimes dark clouds are gathering.
Why sometimes there are clouds in the sky and sometimes there are no clouds? How are clouds formed? What is it made of? Clouds floating in the sky are composed of many tiny water droplets or ice crystals, some of which are mixed together. Sometimes it also contains some big raindrops and ice particles. The bottom of the cloud does not touch the ground and has a certain thickness.