Measurement and modelling of
reactive trace gas fluxes from the
(Amazonian rainforest?)(CLAIRE-UK)
urban (ClearfLo), rural (ECLAIRE)
and background sites
Amy Valach
Supervised by Prof. Nick Hewitt et al.
Lancaster Environment Centre
Background
• Volatile organic compounds (VOCs) from biogenic and anthropogenic
sources (fig. 2) affect atmospheric chemistry (PAN, O3, SOA formation).
• >50% biogenic VOC emitted from tropical forests (fig. 3).
• Major component is isoprene with total global emissions of 600 Tg per
annum (Guenther et al. 2006).
• Isoprene emissions are under circadian control, but also depend on light
(PAR) and temperature.
• Lack of data on isoprene emissions in the tropics from direct
quantification studies.
Biogenic
VOCs
Anthropogenic
VOCs
Fig. 2 (left) The contribution of
biogenic and anthropogenic
organic carbon emissions in
Tg/ a vs. latitude.
Fig. 3 (right) The
distribution of isoprene
emissions in g/m 2a.
CLAIRE-UK Aims
• Quantify bVOC in the Amazon
(pristine forest site for
background values).
• Proton transfer reaction mass spectrometer (PTR-MS)
measures VOC concentrations.
• Use with sonic anemometer to measure fluxes by eddy
covariance method.
• Investigate temporal cycles (seasonal and diurnal) of
isoprene emissions.
Additional work
•
Anthropogenic VOCs in urban and rural
environments affect air quality.
•
Seasonal variability (Jan/Feb and July/Aug)
of VOC fluxes in London (ClearfLo):
•
–
Urban background site (North Kensington)
–
Kerbside site (Marylebone Road)
–
Central city site (KCL Strand flux tower)
VOC fluxes in the Po Valley, Italy (ECLAIRE):
–
High pollution area in Europe
–
Effects on atmospheric chemistry during
summer (Jun/July)
ClearfLo I preliminary results
•
ClearfLo I Jan/Feb & ClearfLo II Jul/Aug/Sep
•
Measured a range of biogenic and anthropogenic VOC species
(concentrations and fluxes)
•
Compare data with different temporal resolutions (5min – 1h)
<- MRd
NK ->
ECLAIRE (Italy)
• Rural/agricultural area
• Very high air pollution
• 40m flux tower in Bosco Fontana
nature reserve
• Flux measurements and withincanopy gradient concentrations
• June-July flux:
Thanks!