The following figure shows the weather map of parts of China for two days, where H is high pressure and L is low pressure. Look at the picture and answer the following questions. (1) means 20 and 2 1

The following figure shows the weather map of parts of China for two days, where H is high pressure and L is low pressure. Look at the picture and answer the following questions. (1) means 20 and 2 1 respectively. On the 20th (1), the air pressure was low (or 1006— 1008), the temperature was high and the weather was fine. 2 1 day air pressure rises (or1008-10/0), wind force increases, temperature drops, and rainy weather occurs.

Before the cold front crossed the border on the 20th, Ganzhou was controlled by the heating group.

2 1, Ganzhou is experiencing (or being affected by) a cold front.

(2) Sketch (north wind or northwest wind)

The wind on 2 1 day is stronger than that on the 20th, because the isotherm of 2 1 day is denser than that on the 20th.

(3) Weather phenomenon: it may bring strong winds, heavy precipitation and storm surge (or rainstorm).

Impact:

Advantages: abundant precipitation can supplement fresh water (or groundwater and surface water) on land and alleviate high temperature and drought.

Disadvantages: damage to farmland, trees, roads, buildings and other facilities, resulting in property and casualties. (reasonable)