WITH reference to the query posed by contributor Geoff Back from his photograph over houses in Sully showing a yellow/green haze (Penarth Times, May 1).
I believe I have the answer. What has been photographed is actually over the far side of the Bristol Channel some10 miles away and it is smoke which has come from a ship's funnel.
This phenomenon appears to occur when there is little or no wind over the Bristol Channel. Under these precise conditions the smoke plume from ships sailing east to west down the Channel tends not to disperse into the upper air but lies as a long plume up to 20 miles long at times, often appearing as far back as Avonmouth and visible down as far as Burnham.
On a number of occasions, by simply following the line of the plume I have actually seen the ship right at the beginning of the plume indicating exactly where it is coming from. But it must be a windless day.