Forecasts of global warming therefore always consider the degree of cloud cover and distinguish between cloud-free and cloudy areas in the atmosphere. The studies of Ilan Koren and his colleagues now show that these areas are less clearly distinguishable from each other than previously thought, since the clouds are surrounded by an invisible haze. The cloud fog is already hinted at on digital photos by simple image processing steps, explain the researchers. With the help of satellite imagery and exposure meters, meteorologists examined the diffuse transition area more closely. They found that the veil spreads around the cloud for at least twenty to thirty kilometers and has a significant effect on the brightness.
The extensive haze does not occur in all cloud types. In normal cloud cover, however, the scattered invisible particles comprise about two-thirds of the sky areas, which were previously classified as cloud-free in the models, the scientists estimate. How much the veil actually affects the climate is still unclear. However, climate models have probably underestimated the effect so far, which is why model results and satellite measurements often did not agree.Nature, online service Original text: Ilan Koren (Weizman Institute Rehovot) et al .: Geophysical Research Letters, vol. 34, L08805 ddp / science.de? Claudia Hilbert ad