Some further observations from aircraft of frost point and temperature up to 50,000 ft

During 1955, 46 measurements of frost point and temperature were made at varying altitudes up to about 50,000 ft using a Dobson‐Brewer pressurized frost‐point hygrometer and a flat‐plate thermometer mounted on the Canberra aircraft of the Meteorological Research Flight. The general character of these ascents in the lower stratosphere confirms the conclusions of earlier papers (Murgatroyd, Goldsmith and Hollings 1955). The mean frost point at 48,000 ft for the ascents made in 1954 and 1955 is ‐117°F and at 46,000 ft ‐115°F, with a standard deviation of about 3°F in each case.