WP4 Tropospheric composition

Reeves, Coe, Heard, Lewis, Monks, Pyle

In the case of WP4 the objectives have been subdivided so that individual groups (first-named) lead the activity in that area:

WP4.1 UEA, UMIST, Leeds, York, LeicesterWP4.2 UMIST, UEA, YorkWP4.3 Leicester, Leeds, UEAWP4.4 Leeds, Leicester, York, UMISTWP4.5 Cambridge

Interactions between the land surface, monsoon dynamics and atmospheric composition.e.g. land surface affects surface temperature, which affects

• biogenic emissions

• monsoon dynamics and subsequently rainfall and thus emissions

Isoprene emissions

Surface Temperature

Surface Vegetation and Soil

Isoprene

Biogenic Emissions Mat Evans – GEOS-CHEM

HIGH AFRICAN BIOGENIC VOC EMISSIONS

SEEN BY GOME T. Kurosu (SAO) and P. Palmer (Harvard)

Anthropogenic v NaturalSources of NOX

Mat Evans – GEOS-CHEM

Western Africa is one of the world’s most active lightning regions !

LIS lightning flashes (2000)

DJF

JJA

Mat Evans – GEOS-CHEM

Vertical Distribution ofEmissions

Redistribution by Convection etc.

Seasonal variation of ATSR fire counts.

Western Africa is one of the world’s most active biomass burning regions!

Summer season

Winter season

Aerosols (dust, biomass burning, secondary organic aerosols)

African outflow

SeaWiFS image – 26/02/00 (NASA/GSFC and ORBIMAGE

Infra-Red Difference Dust Index – July 1983-98 (Brooks and Legrand, 2000)

WP4.1 To make, for the first time, comprehensive observations of the atmospheric composition within the WAM , and thereby to characterise the composition (trace gases and particles) of the different zones within the WAM system.(UEA, UMIST, Leeds, York, Leicester)

GEOS-CHEM - 1997 TOMS (CCD)- 1997

JJA

SON

MAM

DJF

Large difference between model and TOMS tropospheric OLarge difference between model and TOMS tropospheric O33 columns over W. columns over W. AfricaAfrica

Martin et al. [2002]

Dust

SavannaAnthropogenic

Biofuel

Forest

Biomass Burning

Ocean

Monsoon Flux

Harmattan Flux

Tropical rain forest (broadleaf evergreen)

Deciduous forest – woodland savannah

Brush-grass savannah

Steppe (grass, brush, thicket)

Semidesert

Desert

WP4.2 Relate the composition observed in the boundary layer to land surface and vegetation characteristics, as derived from satellite and ground-based observations in WP1 and WP2, and make a first attempt to derive airborne vertical fluxes of biogenic VOCs within the WAM.(UMIST, UEA, York)

WP4.3 Use the improved understanding of the dynamics (WP3) to evaluate the role of the monsoon circulation in transporting chemical constituents within the WAM region (e.g. boundary layer to mid-troposphere). (Leicester, Leeds, UEA)

Latitude-pressure plot of equivalent potential temperature, with SAL boundaries (solid lines) and mixed layer (dashed), from JET2000 dropsondes.

WP4.4 Use the observational dataset to provide improved constraints on our understanding of how natural emissions (VOC and NOX) impact the chemistry (e.g. O3, HOX, secondary organic aerosol) of the WAM region, and the production of constituents that may be transported both into the TTL (WP5) and over regional and continental scales. This objective will relate the chemical control of the particulate material to its ability to act as cloud condensation nuclei and to affect the radiative properties of the particulates.(Leeds, Leicester, York, UMIST)

H. Coe

2.5

2.0

1.5

1.0

0.5

0.0

dM/d

logD

a (µg

m-3

)

2 3 4 5 6 7100

2 3 4 5 6 71000

2

Aerodynamic Diameter (nm)

NOz/NOy (PCA) = 0.17Toluene / Benzene = 3.38

4

OrganicsSulphateNitrateAmmonium

WP4.5 Include the improvements made in the understanding of emissions (WP4.2), chemical degradation pathways (WP4.4) and on the temporal and spatial distribution of constituents (WP4.1, 4.3) in suitable models to investigate the global impact of biogenic emissions from the WAM region on the burden of O3.(Cambridge)

Link between TOMCAT and UMUM dynamics evaluated by other components within AMMA UK

GEOS-CHEM - 1997 TOMS (CCD)- 1997

JJA

SON

MAM

DJF

Martin et al. [2002]

Project structure

WP2:Micromet+ health

WP1: Land surface

WP3:Monsoon

dynamics +convection

WP5: TTL

WP4:Troposphericcomposition

land surfaceanalyses

land surfaceanalyses

micromet foremissions

land surfaceanalyses

global and mesoscale casestudies and trajectories

global andmesoscalecase studiesandtrajectories

global andmesoscalecasestudies

biogenic activitypatterns

chemical tracers

tropospheric inputinto convectionTTL PV

anomalies TTLexchangeestimates UEA

Cambridge Leeds

Leicester UMIST

York

Leeds

CEH Wallingford

Cambridge

Liverpool

Input to WP4

Output from WP4

Links to AMMA-EU

WP2.4 Aerosol and chemical processes in the atmosphere

AMMA-EU Kick-off meetingWP2.4 Workshop on Wed 16 Feb pm