What are the weather symbols on the upper and lower points of the two circles?

grade

1, mild haze: air relative humidity is less than or equal to 80%, visibility is more than or equal to 5km and less than10km;

2. Mild haze: the relative humidity of the air is less than or equal to 80%, and the visibility is more than or equal to 3 kilometers and less than 5 kilometers;

3. Moderate haze: the air relative humidity is less than or equal to 80%, and the visibility is more than or equal to 2 kilometers and less than 3 kilometers;

4. Severe haze: the air relative humidity is less than or equal to 80%, and the visibility is less than 2 kilometers.

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.