The sun sends a broad spectrum of light to the earth. Part of this spectrum is absorbed by the earth’s atmosphere, yet the total power reaching the surface of the earth can still be as high as 1000W/m².
The spectrum of this solar light is shown in the graph on the right.
This graph shows how much radiation there is in a particular colour (wavelength). If the wavelength is longer than 0.7 micrometer (7×10~7m) it is above the visible spectrum and is called Near Infra Red (NIR). Although we cannot see it, we feel it as heat.
All of the power in the solar spectrum, including the NIR, contributes to grass heating. This occurs in natural grass in the same way as in synthetic turf.
However, natural grass cools very efficiently by evaporation of water, whereas the reduction of water usage is one of the strongest arguments for choosing synthetic lawn. Hence if synthetic turf needs to be cooled, this must be achieved by a solution other than water.
The heating effect on the synthetic turf is reduced by reflecting the NIR light. This is shown in the figure below. Natural grass and traditional synthetic turf absorbs light including the NIR. Oasis contains pigments that reflect this part of the spectrum. Thanks to this effect, less light is absorbed by the face yarn resulting in a lower surface temperature.
The NIR reflection can be seen in this picture taken with a special filter which excludes the visible light. This shows the reflection of the NIR light from two types of turf when illuminated by a halogen light source, simulating natural sunlight.
The left side (Oasis) is much brighter than the right side (traditional turf) which means it reflects the NIR light better than the traditional turf.