OBSERVER: CAMS, the Copernicus service that helps protect your skin from the summer sun

OBSERVER: CAMS, the Copernicus service that helps protect your skin from the summer sun

OBSERVER: CAMS, the Copernicus service that helps protect your skin from the summer sun

Thu, 07/07/2022 – 09:48

Something to keep in mind for your sunny holiday.

Summer has come to the Northern Hemisphere and European citizens are preparing their “must-have” products for their holidays. A usual suspect, sunscreen, figures at the top of the list. When the blazing summer sun is high in the sky, solar ultraviolet (UV) rays can damage the skin and eyes. But what is UV radiation and how can Copernicus help us protect ourselves from it?

UV rays are a very energetic radiation with wavelength between 100 and 400 nm.  While they make up about 10% of the Sun’s overall electromagnetic radiation, our star is not their only source. They can also be artificially generated through tanning beds, fluorescent or incandescent lights and certain types of lasers.

The UV radiation wavelength is divided into three bands: UVA (315-400 nm), the longest waves affecting the dermis and potentially causing photoaging and skin cancer; UVB (280-315 nm), shorter waves that affect the epidermis and can cause sunburn; and UVC (100-280 nm), the shortest waves that are filtered out by the ozone layer, and so do not affect the skin. As sunlight passes through the atmosphere, all UVC and almost 90% of UVB radiation is absorbed by ozone, aerosol, water vapour, oxygen, and carbon dioxide. Because UVA radiation is less affected by the atmosphere, it reaches Earth’s surface in a greater amount than UVB. Additionally, the amount of radiation penetrating the atmosphere and reaching the ground depends on several factors, including the Sun’s height in the sky, cloud cover, the thickness of the ozone layer, and geographical location (latitude, elevation). Surface reflective properties (snow, water, sand and vegetation, for example) also play a role in the amount of UV experienced.

How Copernicus monitors solar UV radiation





As part of its monitoring of UV radiation, the Copernicus Atmosphere Monitoring Service (CAMS) provides clear-sky UVI and total-sky UVI forecasts. UVI is the Ultraviolet Index, a standard measurement of sunburn-producing UV radiation. The clear-sky UVI is valid for cloud-free conditions, whereas the total-sky UVI includes the impact of actual or predicted cloud cover as well. The CAMS model calculates solar irradiance at a 5 nm spectral resolution, and the UVI is determined from the sunlight wavelengths that can cause sunburn (also known as erythema), for both UVA and UVB radiation. To reflect the effect of these different wavelengths on sunburn, the UV power spectrum is weighted by a curve known as the erythemal action spectrum. The outcome is the amount of UV radiation at a specific moment in time for a given biological effect. The levels of UV radiation and UVI value change substantially throughout the day. Clear-sky UVI is highest in the four-hour period around solar noon, whereas total-sky UVI depends on cloud cover and fluctuates throughout the day. The map viewer within the European Climate and Health Observatory presents the maximum daily UVI value, calculated based on the CAMS hourly forecast.

Atmosphere composition forecasts underpin UVI forecasts

CAMS produces global forecasts for atmospheric composition twice a day. The composition includes more than 50 chemical elements (e.g. ozone, nitrogen dioxide, carbon dioxide) and seven types of aerosols (i.e. desert dust, sea salt, organic matter, black carbon, sulphate, nitrate, and ammonium aerosol). The forecast is based on a model predicting how the concentrations of these elements will change over the next five days. A combination of the previous forecast with current satellite observations — the so-called data assimilation process — is the first step taken to provide a complete and consistent dataset and allow estimates at locations where observation data coverage is low, or for atmospheric pollutants for which no direct observations are obtainable. Once a year, the CAMS global forecasting system undergoes upgrades that may involve changes in the horizontal or vertical resolution, the addition of new chemical elements, and other improvements in the accuracy of the forecasts. Embedding the UVI calculations in the CAMS global forecasting system ensures a consistent use of the required information on ozone, aerosol, and clouds. Thanks to the CAMS map viewer, we have an indication of the amount of UV radiation across Europe forecast for the following four days, so we can protect ourselves while enjoying the summer holidays. Forecasts for locations in the rest of the world are accessible through the Atmosphere Data Store and as CAMS daily maps.

CAMS map viewer for total-sky UVI

High quality CAMS UVI forecasts are available openly and freely, as with all Copernicus products. As a result, they are used by a large number of websites and applications for mobile devices, and it is likely that, if you check UVI forecasts on your phone or computer, the information you get will be coming originally from CAMS. The CAMS team are particularly proud that their information powers the SunSmart App, launched by the World Meteorological Organization (WMO), the World Health Organization (WHO), the United Nations Environment Programme (UNEP) and the International Labour Organization (ILO). The app provides CAMS five-day global forecasts by location in a searchable format. It highlights time slots when sun protection is required with the aim of helping people around the world know when to use sun protection, in an effort to reduce the global burden of skin cancer and UV-related eye damage.

Thu, 07/07/2022 – 12:00

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