Complex sentence: Turner exhibited watercolours each year at the academy while painting in the winter and travelling in the summer widely throughout Britain, particularly to Wales, where he produced a wide range of sketches for working up into studies and watercolours.
Split into simpler sentences: Turner exhibited watercolours each year at the academy--travelling in the summer and painting in the winter. He travelled widely throughout Britain, particularly to Wales, and produced a wide range of sketches for working up into studies and watercolours.