Royal
Netherlands
Meteorological
Institute
Section of
Atmospheric
Composition
Estimates of Stratosphere-Troposphere Exchange:
Sensitivity to Model Formulation and Horizontal Resolution.
P.F.J. van Velthoven and H. Kelder
J.Geophys.Res. 101, 1429-1434, 1996.
ABSTRACT:
The vertical transport between the stratosphere and the troposphere is studied
by evaluating a matrix that
gives the amount of air that is transferred between the different model layers
of a 3-dimensional off-line
transport model coupled to ECMWF analyses. The latitudinal structure of
vertical exchange reflects the
Hadley circulation with upward transport in the tropics and with downward
transport at mid-latitudes.
Maxima in downward transport occur near the subtropical and polar jet streams.
Its seasonal cycle and the
asymmetry between the two hemispheres are at least qualitatively represented by
the model. However, it
is found that the evaluated total amount of air transferred from the
stratosphere to the troposphere per
month is sensitive to the chosen horizontal model resolution. Refinement of
this resolution from 8°×10° to
4°×5°
leads to almost a doubling of the computed downward transport. Also, the
vertical transport is
found to depend strongly on changes in the formulation of the parent model
(ECMWF). It is, therefore,
important to use internally consistent meteorological input data when
performing multi-year simulations
with off-line Chemistry-Transport Models.
Copyright © KNMI ---
Last modified: Thursday, 10-May-2001 10:17:39 UTC
