High school geography is fast! How to judge nature, wind direction,

Taking the northern hemisphere depression (cyclone) as an example (figure 1), this paper introduces the interpretation of frontal cyclone map.

(1) Determine the position of the front: In a low pressure (cyclone), the narrow area where the low pressure extends outward is called a trough of low pressure. The line connecting the points with the largest bending on the isobar in the low-pressure groove is called the groove line, as shown in Figure 1, AB, CD. Fronts are mostly formed in the trough of low pressure of surface cyclones, namely AB and CD in Figure L, because the wind direction shears near the trough of low pressure AB and CD, which makes the wind directions at E and G in front of the trough of AB and CD different from those at F and H behind the trough, and the air flow properties are also different. They meet with CD in the trough of low pressure, forming a front.

(2) Determine the wind direction near the front: According to the wind direction map of the northern hemisphere, the wind direction near the front can be determined, as shown in figure 1, where f and g are northerly winds and e and h are southerly winds.

(3) Determine the nature of airflow (air mass): In figure 1, points F and G are located on the north side of the front, and the wind blows from the north and comes from high latitudes, while points E and H are just the opposite, so the temperatures of points F and G are lower than those of points E and H in the south, so it is determined that points F and G are cold air masses, and points E and H are warm air masses.

(4) Determine the nature and moving direction of the front: According to the wind direction at points E, F, G and H in the figure and the nature of cold and warm air masses, AB can be determined as a cold front and CD as a warm front. And it can be determined that the front should move counterclockwise with the airflow.

5) Determine the weather in the cyclone control area: As can be seen from the figure, the cyclone front is controlled by the CD warm front, so a wide warm front cloud system and the accompanying continuous precipitation weather appear at the front G; The back of cyclone is controlled by AB cold front, so it is angry. The back of the cyclone is controlled by the AB cold front, so there is a relatively narrow cold front cloud system and precipitation weather at F behind the front, and the weather in the middle of the cyclone is controlled by the warm air mass.