TY  - JOUR
AU  - Ehhalt, D. H.
AU  - Rohrer, F.
AU  - Blake, D. R.
AU  - Kinnison, D. E.
AU  - Konopka, P.
TI  - On the Use of nonmethane hydrocarbons for the Determination of Age Spectra in the Lower Stratosphere
JO  - Journal of Geophysical Research
VL  - 112
SN  - 0148-0227
CY  - Washington, DC
PB  - Union
M1  - PreJuSER-57411
SP  - D11208
PY  - 2007
N1  - Record converted from VDB: 12.11.2012
AB  - On 9 April 2001, while approaching the West Coast of the North American continent, flight 20 of the NASA TRACE P campaign penetrated deeply into a stratospheric intrusion. From measurements aboard that flight we derive vertical profiles of nonmethane hydrocarbons (NMHCs) and other short-lived trace gases in the lower stratosphere using Dichlorofluoromethane, CF2Cl2, as the altitude scale. All profiles show an exponential decrease, which permits the description of their vertical distribution by a single parameter, the scale height. These scale heights are shown to be related to the respective lifetimes in a unique fashion. Using the approximation of a 1-D diffusive model with a constant eddy diffusion coefficient, K, and assuming constant lifetimes, we establish an analytical solution for this relation. By fitting this theoretical expression to the experimental data we can estimate K and thus obtain an approximate age spectrum of the form given by Hall and Plumb (1994). A much better fit to the experimental scale heights is obtained, when we allow the lifetimes to be height-dependent and calculate the theoretical scale heights numerically from a 1-D model. An optimization also suggests a constant K, but with a value of 0.46 m(2)/s, larger than those obtained from the fit of the analytical solution. The obtained age spectra should be valid for transit times not longer than 300 days.
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000247534200002
DO  - DOI:10.1029/2006JD007686
UR  - https://juser.fz-juelich.de/record/57411
ER  -