StraPolEte : Workpackages
Strategy
The core of the project is based on measurements
obtained during an Arctic campaign involving six flights of balloon-borne
instruments in August 2009. The project is divided into 6 workpackages (WPs).
The first one is dedicated to the preparation of the campaign, the finalization
of some instrumental developments and flight coordination during the campaign.
Highly sensitive measurements will be provided and will serve the scientific
objectives divided into four scientific WPs. For each WP, additional
measurements from instruments onboard satellite platforms will be used and
systematic comparison will help for data interpretation. The data set obtained
from balloon-borne instruments and satellites will allow us to provide a
detailed picture of the polar stratosphere in August. Concerning the modeling
approach the goal is twofold with firstly an assessment of their operational
results from comparisons with measurements and secondly detailed investigations
to highlight key processes controlling the stratosphere composition and to
improve the model calculations.
The five scientific WPs are :
Campaign
Coordinators: V. Catoire and G. Berthet (Partner 1)
Dynamical investigations
Coordinators: N. Huret and F. Lefèvre (Partner 1 and 4)
Stratospheric aerosol characterization
Coordinator: J.-B. Renard (Partner 1)
Bromine budget investigations
Coordinator: G. Berthet (Partner 1)
Reference state determination before the settling of the winter polar conditions
Coordinator: S. Payan (Partner 2)
Measurements and data set
Data set used come from measurements obtained during the campaign
(August 2009) by balloon borne instruments and by satellite
plateform since the vortex breakdown ( March 2009) to autumn (2009)
September 2009
Instrument |
Measurement technique |
Measurements used |
Retrieval altitudes provided & vertical resolution |
SPIRALE (Partner 1) |
In situ Direct Infra-red absorption |
O3, CH4, N2O, HCl, CO, HNO3, NO2, OCS |
10km-35km 5m |
IASI-Balloon (Partner 2) |
Remote sensing Infra-red, nadir and limb |
CO, CH4, CO2, OCS |
Partial columns |
LPMA (Partner 2) |
Remote sensing Infra-red solar Occultation |
O3, HNO3, NO, NO2, CH4, N2O, HCl |
15km-35km 1km |
DOAS (Partner 2) |
Remote sensing UV Solar occultation |
BrO |
15km-35km 1km |
SALOMON-N2 (Partner 1) |
Remote sensing UV-visible solar pointing |
O3, NO2, BrO, aerosol extinction |
15km-35km 1 km |
STAC (Partner 1) |
In situ aerosol counter |
Size distribution of aerosols |
10km-35km 10m |
MicroRADIBAL (Partner 3) |
Remote sensing Scattering and polarization by photopolarimetry |
Nature (liquid, solid), size distribution of aerosols |
15km-35km 1km |
Table 1: Balloon-borne instruments involved in the project
Instrument |
Measurement technique |
Measurements used |
Approximate retrieval altitudes provided & Vertical resolution |
GOMOS (ENVISAT satellite) |
Stellar occultation UV-visible and near-Infra-red |
O3, NO2, aerosol extinction |
18km-40km 2-3km |
MIPAS (ENVISAT satellite) |
Infra-Red atmospheric emission |
O3, N2O, CH4,CO , NO2, HNO3, N2O5 |
18km-40km 3km |
IASI (MetOp satellite) |
Infra-Red Nadir pointing |
O3, CO, CH4, N2O, O3 |
Column and partial column |
MLS (EOS Aura satellite) |
Microwaves |
H2O, N2O, O3, CO, HNO3, HCl |
18km–40km |
Table 2: Satellite measurements of interest for the project
Model
Four models will provide simulations; they differ in
the processes there are able to investigate.
MODEL |
Type |
Scale |
Characteristics |
Outputs |
FLEXPART (ECMWF) |
Trajectories calculations |
Global & synoptic |
ECMWF fields |
Air mass origin |
REPROBUS (Partner 4) |
Tridimensional chemical transport |
Global |
Comprehensive chemistry |
Chemical species maps and vertical profiles |
MIMOSA (ETHER data base) |
Tridimensional dynamics |
Global & synoptic |
High resolution PV advection |
Potential vorticity maps |
MIMOSA_CHIM (Partner 4) |
Tridimensional chemical transport |
Global & synoptic |
Advection on isentropic surfaces + Comprehensive Chemistry |
Tracers (N2O, CH4) maps and vertical profiles |
FLEXPART is an atmospheric
trajectory model used by
34 groups from 17 countries. FLEXPART will be driven offline
with meteorological input data from the
European Centre for Medium Range
Weather Forecasts (ECMWF). The model is freeware:
http://zardoz.nilu.no/~andreas/flextra+flexpart.html.
Trajectory calculations associated with the points on the vertical profiles
obtained by the all the balloon instruments give information on the origin of
the sounded air masses.
REPROBUS
(Reactive Processes Ruling
the Ozone Budget in the Stratosphere) is the stratospheric 3D chemical
transport model (CTM) developed at Service d’Aéronomie for more than 10 years
(e.g. Lefèvre et al., 1998). Transport and temperatures are driven by the ECMWF
operational analysis. The model computes the evolution of 55 species through
about 160 photolytic gas-phase and heterogeneous reactions. 40 species or
chemical families, typically long-lived tracers, are transported by a
semi-Lagrangian code. In StraPolEté will be used the recently improved version
of REPROBUS including an explicit description of the inorganic bromine (Br
y)
budget. The model is particularly well adapted to follow stratospheric global
distribution of tracers and reactive species.
The
MIMOSA model
(Modèle Isentropique de transport Mésoéchelle de l’Ozone Stratosphérique
par Advection) is based on the advection of PV. It starts from a PV field on an isentropic
surface provided by ECMWF analysis and interpolated on a fine horizontal grid
that can be chosen at 3 pt/degree or 6 pt/degree. The model creates
operationally high resolution PV maps and can be run on various isentropic
levels from 350 K upwards (Hauchecorne et al., 2002). PV maps are useful tools
to follow large scale isentropic transport.
The
3D CTM MIMOSA-CHIM
(Modele Isentropique de
transport Méso-échelle de l´Ozone Stratosphérique par Advection avec CHIMie) is
the combination of the dynamical model MIMOSA and the chemistry scheme of 3D
CTM REPROBUS (Lefèvre et al.,
1998; Tripathi et al., 2006). The diabatic transport of air
across isentropic surfaces is computed from the heating rates calculated using
the radiation scheme of the SLIMCAT model taken from MIDRAD (Chipperfield et
al., 1999). It provides
time evolution of 40 chemical species fields with high horizontal resolution
and has been developed to follow the detailed transport processes such as
filamentations.