Trends in stratospheric humidity and the sensitivity of ozone to these trends

摘要: Measurements of stratospheric water vapor and methane from the Halogen Occultation Experiment (HALOE) mounted on Upper Atmosphere Research Satellite (UARS) are used to investigate changes in over period 1992–1996 inclusive. An increase mixing ratio is found at levels between 30 km 65 across globe which fit, first order, a linear trend varying with altitude 40 parts per billion by volume year (ppbv yr−1) maximum 90 ppbv yr−1 45 km. These trends appear be greater than that expected due growth tropospheric past several decades, possible mechanisms accounting for this discussed. The combined budget 2 × CH4 + H2O approximately constant global mean value 61±4 yr−1. On basis these estimates, sensitivity studies have been performed using two-dimensional (2-D) radiative-chemical-dynamical model assess impact concentrations ozone degree change timescales consistent doubling CO2 scenarios. We find increased enhance midstratosphere ∼1–2% compared response itself ∼5–10%. In upper stratosphere destruction enhanced changeover production loss lowered ∼50 (from ∼70 km). A chemical mechanism processes involving OH NO2 identified.