TY  - JOUR
AU  - Rohs, S.
AU  - Schiller, C.
AU  - Riese, M.
AU  - Engel, A.
AU  - Schmidt, U.
AU  - Wetter, T.
AU  - Levin, I.
AU  - Nakazawa, T.
AU  - Aoki, S.
TI  - Long-term changes of methane and hydrogen in the stratosphere in the period 1978-2003 and their impact on the abundance of stratospheric water vapor
JO  - Journal of Geophysical Research
VL  - 111
SN  - 0148-0227
CY  - Washington, DC
PB  - Union
M1  - PreJuSER-50145
SP  - D14
PY  - 2006
N1  - Record converted from VDB: 12.11.2012
AB  - The long-term changes of the stratospheric mixing ratio of CH4 over the period of 1978-2003 are derived from balloon-borne data of H-2, CH4 and N2O. The data were obtained by collecting whole air samples and subsequent gas chromatographic analyses. To eliminate the short-term variability attributed to dynamical processes, the N2O mixing ratio is used as a proxy for altitude. A correlation analysis for the individual years is applied and the CH4 mixing ratios are interpolated to four different levels of N2O, corresponding to altitudes of approximately 17, 23, 26 and 30 km at midlatitudes. For the investigated period of 1978 to 2003 we find increases at the four levels of 207 +/- 32 ppb, 159 +/- 21 ppb, 140 +/- 34 ppb and 111 +/- 60 ppb, respectively. The CH4 trend has slowed down in recent years and is best fitted by a second-order polynomial. The increase of CH4 can account for only 25-34% of the increase in stratospheric H2O of 1%/yr over the last decades as derived from previous studies. The simultaneously measured time series of stratospheric H-2 mixing ratios shows that the contribution of stratospheric H-2 to the H2O trend in the period 1988-2003 is minor.
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000239490100003
DO  - DOI:10.1029/2005JD006877
UR  - https://juser.fz-juelich.de/record/50145
ER  -