Exponential prediction of ultraviolet index

Ultraviolet index forecast is a very useful forecast in daily life. According to the ultraviolet index published in the forecast, some measures can be taken to prevent ultraviolet rays. Of course, ultraviolet is not a terrible thing, and we should not be unilaterally affected by ultraviolet forecast.

According to the published ultraviolet index, it is necessary to take effective measures to prevent excessive ultraviolet radiation and make effective use of ultraviolet radiation in a suitable time. The intensity of ultraviolet radiation is not constant in a day, and the most important time in a day is from 10 to around 3 pm. Of course, according to the weather changes, the amount of ultraviolet radiation is also changing, so we should also pay attention to the daily weather changes, and pay attention to which time period we should be particularly careful according to the weather changes.

The amount of ultraviolet rays reaching the surface varies with different geographical locations, seasons, climate and weather. From September 1 day, "12 1" will automatically answer the phone, and the column "Health and Meteorology" will be added, including the daily ultraviolet intensity and meteorological knowledge related to health, which will be provided to you at any time. Please call 12 1 at any time to find out the latest ultraviolet intensity and the useful suggestions provided by the Meteorological Observatory. The ultraviolet index refers to the degree of damage that the ultraviolet radiation in the sun rays reaching the ground may cause to human skin when the sun is at the highest position in the sky in a day (usually around noon).

The ultraviolet index is represented by the number 0- 15. Generally speaking, the ultraviolet index at night is 0, and in tropical and plateau areas, the ultraviolet index on sunny days is 15. The greater the ultraviolet index value, the more serious the erythema damage caused by ultraviolet radiation to human skin. Similarly, the greater the ultraviolet index value, the stronger the damage to the skin in a short time. When the ultraviolet index is 0, 1, 2, it means that the amount of ultraviolet rays in solar radiation is the smallest, and this amount has little effect on human body; When the ultraviolet index is 3 or 4, it means that the amount of ultraviolet rays in solar radiation is relatively low, and the possible impact on human body is relatively small; When the ultraviolet index is 5 and 6, it means that the amount of ultraviolet rays is moderate, and it also has moderate harmful effects on human skin; When the ultraviolet index is 7, 8 and 9, it means that there is strong ultraviolet radiation intensity. At this time, it may have a great impact on the human body, and corresponding protective measures need to be taken; When the ultraviolet index is greater than 10, it shows that ultraviolet radiation is very strong and has the greatest impact on human body, so protective measures must be taken. The possible influence of ultraviolet radiation intensity on human body at the level of ultraviolet index and the suggested protective measures.

0-2 1 The weakest security can be avoided.

3-4 2 Wear protective hat or sunglasses when going out normally.

5-6 3 Moderate attention: In addition to wearing protective hat and sunglasses,

Wear sunscreen (SPF index of sunscreen should not be lower than 15).

Avoid going out from 10 a.m. to 4 p.m. in the first 4 hours of 7-9.

When going out, you should stay in the shade as much as possible.

& gt 10 5 is very harmful. Try not to go out. When you have to go out, you should take certain protective measures.

When the ultraviolet ray is the weakest (0-2), it has little impact on the human body, so just wear a sun hat when going out; When the ultraviolet reaches 3-4, you need to wear sunglasses and sunscreen when you go out to avoid the damage of solar radiation to your skin. When the ultraviolet intensity reaches 5-6, you must walk in the shade when you go out; When the ultraviolet rays reach 7-9, it is best not to go to the seaside to bask in the sun during the morning to 4 pm of 10; When the ultraviolet index is greater than or equal to 10, you should try to avoid going out, because the ultraviolet radiation at this time is extremely harmful. The standard method for calculating the ultraviolet index proposed by the World Meteorological Organization and the World Health Organization is to measure the intensity of solar ultraviolet rays with different wavelengths up to 400nm, and multiply the intensity of solar ultraviolet rays with the corresponding weighted value in the erythema spectrum curve to reflect the response of human skin to ultraviolet rays. Add up the results of the above multiplication to obtain the total ultraviolet intensity weighted by erythema spectrum, and the unit is milliwatts per square meter (MW/m2). Then, the total ultraviolet intensity weighted by erythema spectrum is multiplied by 0.04 to obtain the ultraviolet index (unit ultraviolet index is 25mW/m2).

For example, the average amount of ultraviolet rays reaching the ground within 15 minutes of the strongest sunshine at noon is 100mW/㎡, which translates into an ultraviolet index of 4.

As we all know, sunlight is one of the indispensable elements of life. Proper sun exposure is beneficial to the human body: for example, it can enhance the absorption of calcium and phosphorus, which is conducive to the recovery of rickets, rheumatoid arthritis and anemia, and also has a preventive effect on rickets in infants; In addition, ultraviolet rays in the sun have a strong bactericidal ability, and general bacteria and some viruses will be killed if exposed to the sun for half an hour or a few hours; Ultraviolet rays can also turn dehydrocholesterol in the human body into vitamin D, which promotes the calcification and growth of bones, so sunlight also directly affects people's height.

Of course, sunshine and human health are not infinitely proportional. Excessive ultraviolet radiation can cause photocoagulation, inhibit the function of immune system, make people slow down, and can induce diseases of eyes, skin and lungs. The reason why "sunbathing", which was popular in the West in 1970s and 1980s, failed to continue to be popular all over the world is that when sunbathing, the skin was exposed for a long time, which damaged the skin tissue and had a negative impact on health. It is reported that the incidence of skin cancer in Australia, the United States, New Zealand and other countries is very high, which is obviously related to the fact that there are many beaches and people like sunbathing in these countries. Some experts pointed out that the incubation period of skin cancer caused by ultraviolet rays can be as long as several decades, and the influence of ultraviolet rays on human body is accumulated for many years. Paying attention to prevention now is for the sake of future health.

In recent decades, due to the increasingly serious destruction of stratospheric ozone, the amount of ultraviolet radiation received by the ground has gradually increased, and the impact of ultraviolet radiation on human health (mainly skin) has attracted more and more attention. The meteorological department also makes timely ultraviolet index forecast for people to take defensive measures to avoid and reduce the immediate and far-reaching damage of ultraviolet rays to the skin.

In order to make it easy for the public to remember, understand and use, the value of ultraviolet index generally starts from 0 and ends at 10 (including 10 or above). According to these values, the forecast grade of ultraviolet index is divided into five grades. Details are as follows:

The index value is 0 to 2, usually cloudy or rainy, when the ultraviolet intensity is the weakest, and the forecast level is 1 level;

The index value is 3 to 4, generally cloudy. At this time, the ultraviolet intensity is weak, and the forecast level is level 2;

The index value is 5 to 6, which is generally cloudy. At this time, the ultraviolet intensity is strong, and the forecast level is level 3;

The index value is 7 to 9, and it is generally cloudless on sunny days. At this time, the ultraviolet intensity is very strong, and the forecast level is 4;

The index value reaches or exceeds 10, and it is mostly sunny in summer, with particularly strong ultraviolet intensity, and the forecast level is five.

It should be noted that the above index values and intensity grades are the average ultraviolet index and intensity monitored within four hours every day 10- 14 according to the unified regulations of China Meteorological Bureau. Generally speaking, the maximum value of ultraviolet light appears around noon 12. People should try their best to avoid outdoor activities during this period in their daily life (especially in summer). Even in winter, they should choose "prime time" before 10 in the morning and after 3 pm.

Meteorological stations or professional meteorological stations will generally forecast the ultraviolet intensity level of the day through the media before 9: 00 am every day, and forecast the ultraviolet intensity of the next day after 3: 00 pm every day. The public can check the ultraviolet level forecast on TV weather forecast, meteorological websites and newspapers. According to these forecasts, when the ultraviolet level is 3 or above, the most suitable sun protection measures should be taken, such as wearing long-sleeved shirts, sunglasses, playing with a sun umbrella (you can choose an umbrella with anti-ultraviolet function) and applying sunscreen oil. To prevent strong ultraviolet rays from harming people's health and ensure that the skin will not be greatly damaged.