Howard Penman

Howard Latimer Penman (1909 – 1984) was a British meteorologist. He formulated Penman’s Formula, which is used worldwide by meteorologists and agricultural scientists to assess evaporation rates in different setups (lakes and ponds, lawns, cropped fields) and locations in the world. With John Monteith he formulated the Penman–Monteith equation which is used to calculate evapotranspiration and the need for crop irrigation. Penman was a distinguished Rothamsted Research scientist and government advisor, and a well-known local figure in Harpenden.

Early life Howard Penman was born in County Durham and studied at Durham University where he graduated in Physics in 1930. While working for the British Cotton Research Association in Manchester he worked on his thesis for his Ph.D., which was awarded by Durham University in 1938. Bored by the work on cotton dyes he applied in 1937 for a post in the Soil Physics Department at Rothamsted Research, headed by Bernard Keen, for a salary of £320 per annum. He became interested in the records of the drain gauges, and their relationship with rainfall, and from these was able to estimate the rate at which water evaporated from bare soil. From these beginnings some of his major contributions would follow. When war broke out he was recruited by the Admiralty and worked on the sound output of ships and submarines in connection with the development of acoustic mines. In 1944 he was recalled to Rothamsted to work on the physics of wet soil in preparation for the land campaign, where the progress of military vehicles would be vital.