In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 20, No. 2 ( 2020-01-31), p. 1163-1181
Abstract:
Abstract. The effectiveness of transport of short-lived halocarbons to the
upper troposphere and lower stratosphere remains an important uncertainty in
quantifying the supply of ozone-depleting substances to the stratosphere. In
early 2014, a major field campaign in Guam in the western Pacific, involving UK
and US research aircraft, sampled the tropical troposphere and lower
stratosphere. The resulting measurements of CH3I, CHBr3 and
CH2Br2 are compared here with calculations from a Lagrangian
model. This methodology benefits from an updated convection scheme that
improves simulation of the effect of deep convective motions on particle
distribution within the tropical troposphere. We find that the observed
CH3I, CHBr3 and CH2Br2 mixing ratios in the tropical
tropopause layer (TTL) are consistent with those in the boundary layer when
the new convection scheme is used to account for convective transport. More
specifically, comparisons between modelled estimates and observations of
short-lived CH3I indicate that the updated convection scheme is
realistic up to the lower TTL but is less good at reproducing the small
number of extreme convective events in the upper TTL. This study
consolidates our understanding of the transport of short-lived halocarbons
to the upper troposphere and lower stratosphere by using improved model
calculations to confirm consistency between observations in the boundary
layer, observations in the TTL and atmospheric transport processes. Our
results support recent estimates of the contribution of short-lived
bromocarbons to the stratospheric bromine budget.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-20-1163-2020
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2020
detail.hit.zdb_id:
2092549-9
detail.hit.zdb_id:
2069847-1
