How to calculate the human comfort index in weather forecast?

Grade 86-88 4 The human body feels very hot and extremely uncomfortable. I hope to pay attention to heatstroke prevention and prevent heatstroke.

People of grade 80-853 feel hot and unwell, please pay attention to heatstroke prevention and cooling.

Grade 76-79 2 The human body feels hot and unwell, so it can be cooled down appropriately.

71-751The human body feels warmer and more comfortable.

Level 59-700 people feel the most comfortable and acceptable.

Grade 5 1-58- 1 people feel slightly cold and comfortable.

Level 39-50-2 human body feels cold (cold), please pay attention to keep warm.

Grade 26-38-3 human body feels very cold and uncomfortable, please pay attention to keep warm and cold.

& lt25-4 people feel cold and extremely uncomfortable. I hope to keep warm and prevent frostbite.

Brief introduction of human comfort

The subjective feeling of human body to the external meteorological environment is different from the results of various meteorological elements obtained by atmospheric radiosondes. Human comfort index is a bio-meteorological index based on the heat exchange between human body and atmospheric environment, aiming at evaluating human comfort under different climatic conditions from the meteorological point of view.

The physiological functions of human body, such as heat balance function, body temperature regulation, endocrine system and digestive organs, are affected by many meteorological factors. Such as atmospheric temperature, humidity, air pressure, light, wind, etc. Experiments show that humidity has little effect on human body when the temperature is moderate. Because humidity mainly affects the human body's thermal metabolism and water and salt metabolism. When the temperature is high or low, its fluctuation becomes very important to the thermal balance and warmth of the human body. For example, when the temperature is 15.5℃, even if the relative humidity fluctuates by 50%, the impact on human body is only the effect of temperature change 1℃, while when the temperature is 2 1-27℃, when the relative humidity changes to 50%, the heat dissipation of human body is obviously different. When the relative humidity is 30%, the heat dissipation of human body is more than that when the relative humidity is 80%. However, when the relative humidity exceeds 80%, the heat balance of human body will be destroyed because of the influence of high temperature and high humidity on the evaporation of human sweat, so the human body will feel sultry and uncomfortable. With the increase of temperature, this situation will become more obvious. When the weather is cold and humid in winter, due to the high relative humidity in the air, the thermal radiation of the human body is absorbed by the water vapor in the air. In addition, clothes absorb moisture in humid air, which increases the thermal conductivity, accelerates the heat dissipation of the body, and makes people feel cold and uncomfortable. When the temperature is lower than the skin temperature, wind energy accelerates the heat dissipation of the body. Every time the wind speed increases 1 m/s, people will feel that the temperature has dropped by 2-3℃. The stronger the wind, the faster the heat dissipation, and the colder and more uncomfortable people will feel.

Generally speaking, temperature, air pressure, relative humidity and wind speed have the greatest influence on human feelings, and human comfort index is a nonlinear equation based on these four factors.