With relentless high pressure sitting over Western Europe what little cloud there is comprises mainly cirrus, the ice-crystal clouds at high level forming what are known as mare's tails. My attention was caught however by these, which are contrails that have formed a foundation for a broader spread of cirrus, from jets headed north and chances are, across the Atlantic.
During the grounding of airlines following 9/11 it is thought that the skies were 10% clearer due to the absence of water vapour dispensed by jet engines high in the sky that forms a basis for widespread cover of this kind. And so if you were my age then the skies really were bluer when you were a child.
