The weather in April

The distribution characteristics of (1) isobar should be described from the distribution of pressure centers, the gradual change of numerical values and the density relationship of isobar. As can be seen from the figure, there is high pressure in the southwest and southeast, with high pressure center, sparse isobar and small pressure gradient. The air pressure in the north of the central part is low, the air pressure center is low, the isobars are dense, and the air pressure gradient is large.

(2) Formation conditions of sandstorm; Strong wind or strong wind weather conditions; Source basis of dust; Unstable thermal conditions. In addition, drought and lack of rain in the early stage, warming weather and rising temperature are the special weather background for the formation of sandstorms; The formation and development of ground cold front, etc.

So the answer is;

(1) There is high pressure in the southwest and southeast, with high pressure center, sparse isobar and small pressure gradient; The air pressure in the north of the central part is low, the air pressure center is low, the isobars are dense, and the air pressure gradient is large.

(2) Sandstorm

Weather conditions: rising temperature leads to thawing of topsoil, enhanced evaporation, dry surface and abundant sand sources; The warm air mass before the cold front is dry and it is difficult to form precipitation; The cyclone force is strong, and the airflow rises, forming sand blowing; The west wind is strong, forming a large-scale sandstorm.