Water vapour is the predominant gaseous source of infrared opacity in the atmosphere, accounting for about 60% of the natural greenhouse effect for clear skies. Water vapour condenses to produce clouds, changing radiative properties and releasing latent heat that drives or modifies atmospheric circulation systems. Water vapour in the lower stratosphere, though present only in small amounts, is radiatively significant. Consequently, there is potential for additional climate change feedbacks through perturbations of the processes that control the amount of water vapour in the stratosphere, such as the Brewer-Dobson circulation that strongly influences tropical tropopause temperatures and the amount of CH4 oxidized in the stratosphere.
Dale Hurst, Imke Durre
Total column water vapour; Tropospheric profiles of water vapour; Lower-stratospheric profiles of water vapour; Upper tropospheric humidity