The latitudinal and vertical distribution of molecular hydrogen in the troposphere

Meridional profiles of the H 2 mixing ratio in surface air were obtained by continuous registrations during a ship cruise from Hamburg, West Germany, to Santo Domingo, Dominican Republic, in 1973. Vertical and meridional profiles in the troposphere were measured during a research flight from Cologne, West Germany, to Punta Arenas, Chile, in 1974. The average H 2 mixing ratio of surface air was 0.582 ± 0.003 ppmv (parts per million by volume) in the northern hemisphere. In the upper troposphere it was found to be 0.561 ± 0.001 ppmv, 1.3% higher than the average of 0.554 ± 0.002 ppmv in the upper troposphere of the southern hemisphere. The horizontal distribution appears to be rather uniform. The vertical profiles also exhibited a rather uniform distribution of H 2 . However, vertical gradients near the ground were occasionally observed. They are ascribed to strong sources and sinks at the surface. The H 2 mixing ratio in the lower stratosphere appeared to be slightly higher than that in the troposphere.