How to determine the weather system?

To determine whether it is a high-pressure center depends on the numerical changes of the isobars. From the outside to the inside, the value increasing is the high pressure center, which is similar to the top of the contour line. On the contrary, it is a low pressure center.

Specific systems in the flow field, pressure field, temperature field and humidity field that have an important impact on weather formation, or specific weather phenomena.

In the flow field there are waves, cyclones, anticyclones, shear lines, convergence zones, typhoons, jet streams, squall lines, tornadoes, etc.; in the pressure field there are low pressure, high pressure, low pressure troughs, High pressure ridges, etc.; there are air masses, fronts, etc. in the temperature field.

Characteristic scale:

Various types of weather systems have certain characteristic scales. Spatial scale is mainly measured by the horizontal scale of the weather system, which refers to the wavelength or disturbance diameter of the weather system.

The time scale is measured by the length of the life history of the weather system. Life history refers to the life and death process of the weather system from birth to death. Generally, the larger the horizontal scale of a weather system, the longer its time scale.

Before the 1940s, the average distance between ground observation stations was about 200 to 300 kilometers. The high and low pressure systems analyzed based on the observation data were called weather systems. Since the 21st century, It is called synoptic scale weather system.

In the 1940s, high-altitude weather observation was developed (the average station distance is about 500 kilometers), and the fluctuations found on high-altitude weather maps with wavelengths equivalent to the radius of the Earth are called planetary scale weather systems .