The figure below is a schematic diagram of the air pressure changes before and after the passage of different weather systems. The four curves in the figure represent the air pressure changes before a

The figure below is a schematic diagram of the air pressure changes before and after the passage of different weather systems. The four curves in the figure represent the air pressure changes before and after the cold front passes.

C

Test question analysis: From the figure, we can see that weather system b is high pressure and anticyclone, and a is low pressure and cyclone. When a cold front passes through, the air pressure increases and the temperature and humidity drop sharply, corresponding to the C weather system. d is the passage of warm front.

Comments: This question is not difficult. For this question, students need to clearly understand the changing process of weather phenomena when each weather system passes through. As shown in the figure above, a is a low pressure, which is a cyclone. The passing clouds thicken and often lead to rainy weather. D is a warm front, which often causes cloudy days, rainfall and other weather phenomena. After the warm front passes, the warm air mass replaces the original cold air mass. location, so the temperature rises, the air pressure drops, the weather gets sunny, etc. It is not difficult to answer the questions once you have mastered the laws of these phenomena.