Recently, there have been high temperatures and humidity in many parts of the north. Many friends in the north have felt the dampness similar to that in the south and exclaimed, "Biscuits are soft and clothes are spoiled. Isn't there also a 'return to the south' in the north? Beijing is also one of the typical areas affected by this high temperature and high humidity weather. Data shows that from the night of July 3rd to the day of July 4th, the relative humidity in North China reached over 85%, and on July 3rd, the relative humidity in Beijing even briefly reached 100%. Why is the weather in northern regions so humid and hot? Is it normal? On the issue of public concern, the reporter interviewed relevant experts on the 6th. First question: What is the reason for the recent "sauna days" in the north? Sun Jun, the chief forecaster of the Central Meteorological Observatory, introduced that the humid and hot weather in the north this time is closely related to the northward uplift of the Western Pacific Subtropical High. At present, the entire subtropical high pressure system controls most of the central and eastern regions of China, thereby guiding the northward push of the summer monsoon. At present, the northern boundary of the summer monsoon has reached the southern part of Northeast China, the central southern part of North China, and the eastern part of Northwest China. The water vapor and heat carried by the monsoon also follow, forming a high temperature and high humidity weather. Recently, humidity has been relatively high in most parts of North China. Although the highest temperature is around 30 ℃, which does not meet the standard for high temperature (above 35 ℃), humidity has a significant impact on body sensation. In situations where the temperature is not very high but the relative humidity is high, the temperature perceived by the human body will be slightly higher than the ambient temperature. ”Sun Jun said. Xu Xiaofeng, President of the China Meteorological Service Association, also stated that the recent "sauna weather" in Beijing was caused by warm and humid air masses carried by subtropical high pressure to the north. Under the influence of these warm and humid air masses, people feel like they are taking a sauna. Xu Xiaofeng explained that the temperature reported in the weather forecast is the temperature inside a ventilated louver box located 1.5 meters away from the ground in an outdoor environment far from urban construction areas. Currently, this unified standard is used worldwide to measure temperature, so that temperatures in different regions can be compared. And perceived temperature refers to people's perception of temperature in their actual environment, with significant differences. The temperature felt indoors will be different from outdoors, and it will also be different in sunlight and shady places. There will be significant differences in wind conditions, and atmospheric humidity will also significantly affect the sensation. ”Xu Xiaofeng said that perceived temperature can be influenced by various factors, including temperature, humidity, wind, solar radiation, etc. In general, there is a significant difference between the environment in which a person is located and the conditions inside the meteorological observation field's louver box, so there are more situations where people feel high. According to meteorological data calculations, when the temperature exceeds a certain value, the greater the relative humidity at the same temperature, the more significant the increase in perceived temperature. Without considering factors such as wind speed and solar radiation, when the temperature in a place reaches 32 ℃ and the humidity is around 50%, the perceived temperature can reach the high temperature standard. When the relative humidity reaches 100%, the perceived temperature can even exceed 50 ℃. Second question: Will this weather become the norm in Beijing's summer in the future? In fact, Beijing experiences hot and humid weather for a period of time every summer, usually in mid to late July. The reason is that the subtropical high pressure system moves northward, bringing warm and humid air to northern China, resulting in hot and humid weather in the North China region. The hot and humid weather in Beijing has significantly advanced this year. From the current situation, it is at least 10 days earlier, which is related to the changing weather situation in the entire East Asian region. ”Xu Xiaofeng said. Xu Xiaofeng introduced that China belongs to a typical East Asian monsoon climate, and the annual rain belt shows a clear pattern of north-south advance and retreat. From April to June, during the pre flood season in southern China, rain bands are located in Guangdong, Guangxi, and Fujian provinces; June to July is the Jianghuai plum rain season, with the rain belt extending northward to the Yangtze River and Huai River areas; July to August is the rainy season in North China and Northeast China. This is closely related to the northward push of warm and humid air masses carried by subtropical high pressure systems. This year, the rainy season in the Jianghuai River Basin occurred early, and the plum blossoms appeared early. The subtropical high pressure pushed northward, causing early occurrence of humid and hot weather in North China. The situation similar to this year cannot be said to be a new normal, but rather an abnormal one. ”Xu Xiaofeng emphasized that the summer temperature in Beijing has indeed shown an upward trend with the continuous global warming. After the temperature rises, the water vapor content in the atmosphere will also increase. As long as the trend of climate warming is not reversed, this situation is difficult to change. Question 3: What are the effects of "sauna days" on the human body and how can we prevent them? Li Yi, Deputy Chief of the Public Meteorological Service Center (National Early Warning Information Release Center) of the China Meteorological Administration, stated that high temperature and humidity environments can weaken the body's heat dissipation ability, leading to ineffective temperature regulation. Excessive sweating can also cause dehydration or electrolyte imbalance, affecting the function of the circulatory system and leading to symptoms such as dizziness, fatigue, palpitations, etc., which increase the risk of acute attacks of chronic diseases such as cardiovascular and cerebrovascular diseases. For the elderly, pregnant women, children, and patients with chronic diseases, the risks are more prominent. Experts suggest preventing long-term "sauna days" from the following aspects: for the general population, do a good job of indoor cooling, avoid going out in high temperatures, actively replenish water multiple times, and replenish electrolytes in large quantities. For high-risk groups such as the elderly and children, it is necessary to replenish water in a timely manner, cool down from the heat, use air conditioning to reduce humidity appropriately, stay in ventilated and shaded areas, try not to go out, ensure that someone accompanies you when going out, keep in touch, and seek medical attention in a timely manner if necessary. For patients with chronic diseases, it is necessary to follow medical advice for medication, monitor health indicators, and seek timely help if necessary. For outdoor workers, it is necessary to arrange work time reasonably, replenish water and electrolytes in a timely manner, and take protective measures. (New Society)