Long-term changes of hydrogen-containing species in the stratosphere

Abstract

Understanding the 1% per year increase of stratospheric water vapour from 1954 to 2000 is a great challenge in atmospheric science. The increase is predominantly caused by long-term changes in transport of water vapour into the stratosphere and systematic increases of tropospheric methane levels. This paper gives a review on stratospheric water vapour changes for the 1980 and 2000 time period with emphasis on the contribution of methane oxidation. Predictions for 2050 indicate that likely increases of tropospheric methane levels will lead to an increase of upper stratospheric water vapour values of about 0.4 ppmv. A similar value is predicted as an upper limit of effects of a future hydrogen economy. r

Sensitivity of Arctic ozone loss to stratospheric H2O

“…Box model calculations by Röckmann et al [2004] indicate that the projected increase of tropospheric methane by WMO scenarios will lead to an increase of the upper stratospheric H 2 O mixing ratio of about 0.4 ppmv by 2050. A similar increase was proposed by Riese et al [2006] as a realistic upper limit of the impact of a H 2 economy.…”

Total hydrogen budget of the equatorial upper stratosphere

“…However, we will show that the Harries study used HALOE H 2 O and CH 4 measurements which have biases in the upper stratosphere resulting in an underestimate of H 2 losses in this region. We also note a recent modeling study by Riese et al [2006] which showed that estimated increases of tropospheric H 2 of ∼0.55 ppmv from a possible future hydrogen economy would lead to a 0.3–0.4 ppmv increase in upper stratospheric H 2 O due to increased H 2 oxidation.…”

Performance evaluation and comparison of fuel processors integrated with PEM fuel cell based on steam or autothermal reforming and on CO preferential oxidation or selective methanation

“…2, respectively) of the FPU. The recycle of the anode exhaust gas is not only a valuable recovery of heat, but solves also a base problem of PEM-FC: the release in the atmosphere of molecular hydrogen and steam through the anode exhaust is an environmental risk of not yet well-known impacts on the stratosphere, for the possibility of destruction of ozone, changes in tropospheric chemistry, increase in noctilucent clouds, and stratospheric cooling [92][93][94][95][96].…”