Characteristics of summer weather

When it comes to summer, the first thing people think of is heat. Summer is the highest temperature period in a year, with dry and hot inland areas and humid and muggy coastal areas. But the weather in summer is by no means a hot word to sum up. Summer is the most violent and complicated period of the year, and the rainfall in most parts of China is mainly concentrated in this period. In the past 30 years, the annual precipitation in Beijing is 570 mm, and the precipitation in summer alone is 423 mm, accounting for 74% of the annual precipitation, especially at the end of July and the beginning of August, which is often the concentrated period of heavy rain and heavy rain. In addition, lightning, hail, thunderstorms, floods, droughts, typhoons and other disastrous weather also occurred at this time.

One of the important reasons why the weather is so changeable in summer is water vapor. A large amount of water vapor is the basic substance of various weather changes. Speaking of water vapor, we want to introduce a weather system to you, that is, subtropical high. Subtropical high is a high-pressure system located at an average of 35 degrees on the earth and roughly arranged along the latitude circle. The position of subtropical high has obvious seasonal variation. In the northern hemisphere, summer is in the north. Winter is in the south. The airflow rotates clockwise from the center of high pressure, forming a southerly airflow in the west of high pressure. The southerly airflow continuously transports warm and humid air from the ocean to Chinese mainland, thus providing water vapor for rainfall. Once the warm and humid airflow meets the cold air from the north to the south, it will form a wide range of rainy weather. Because the position of this high pressure changes with the seasons, the rain belt in summer in China will advance from south to north in turn. In autumn, with the subtropical high moving south, the rain belt moves south, which is why the rainy season in the south of China starts early, ends late and lasts long, while the rainy season in the north starts late and ends early and lasts short.

The warm and humid airflow south of the edge of subtropical high can bring a lot of water vapor to China, but the interior of subtropical high is often dry and sunny due to the influence of descending airflow. Some abnormal subtropical high movements are the chief culprits of disastrous weather in China.

It is hot in summer, and many functions of human body will change in high temperature environment, especially body temperature regulation, water and salt metabolism, digestion, circulation, nervous system and endocrine system. Once these changes can't adapt to the environment well, people will feel uncomfortable, and heatstroke is the most common situation in summer. In addition, high temperature and high humidity in summer is an active period of bacterial reproduction, and it is also a frequent period of various infectious diseases, especially digestive tract infectious diseases. In order to spend the summer safely, people

Reasonable diet

Eat more light and less greasy food, and eat more bitter vegetables, such as bitter gourd, towel gourd, bitter vegetable and celery. Bitter taste can stimulate appetite, clear heart and strengthen brain, promote hematopoietic function, and clear away heat and toxic materials.

Proper exercise and static.

Exercise should be carried out in the early morning, in the morning and at the relatively cool time of the day, and it is forbidden to exercise in the hot sun. Exercise intensity must be moderate, and the time should not be too long.

An orderly life

Because the heat in summer reduces people's sleep at night, we should take a proper rest at noon to make up for the lack of sleep. In addition, when you sleep, you must pay attention to the fact that the temperature of the air conditioner should not be adjusted too low, generally between 26℃ and 28℃, and you should also pay attention to opening the window frequently to make the indoor air clean.

Clothing science

Summer dress should follow the principle of "cool, simple, loose and beautiful". In summer and hot summer, some people like to go shirtless, thinking that it will be cooler, but it is not. When the temperature approaches or exceeds human body temperature, shirtless clothes are not only not cold, but even hotter, because only when the skin temperature is higher than the ambient temperature can heat be emitted through radiation and conduction.