Vegetation Impacts from Air Pollution focus on O3 · [email protected] HTAP, Potsdam, Germany...

[email protected] HTAP, Potsdam, Germany

Feb 18-19 2016

Vegetation Impacts from Air Pollution – focus on O3

Lisa Emberson, Chris Malley, Patrick Bueker, Steph Osborne

Stockholm Environment Institute (SEI), University of York


Feb 18-19 2016

Ozone O3 injury on spinach, Europe

Source: J. Bender

Source: G. Mills

• Visible injury

• Biomass loss (above and below ground)

• Crop yield loss

van Dingenen et al, 2009

Source: A. Wahid

Other effects not so commonly

recognised by the wider

community….

• Photosynthesis, stomatal

conductance

• Leaf Area Index

• Transpiration

• Yield quality (e.g. N content)

• Carbon allocation

• Reproductive ability

• Etc….


Feb 18-19 2016

KM1: There is evidence that O3 can cause a variety of damage responses

to crops, forests and grasslands. The strength of this evidence varies

with receptor type and location, with more evidence on crops than

forest trees, more on trees than grasslands, and equal evidence in North

America and Europe, but less in Asia.

More evidence now being collected in Asia

HTAP1


Feb 18-19 2016

1. OTC Beijing

2. OTC in Jiaxing

3. FACE in Jiangdu

4. OTC in Guangzhou

5. OTC in Beijing

6. OTC in Harbin

1

2

4

3

5

6

Location of experimental infrastructure across China / Asia


Feb 18-19 2016

Source: G. Mills

Empirical data

Fumigation / Filtration studies

National Crop Loss Assessment Network (NCLAN) - 1980s in North America

European Open Top Chamber (EOTC) – 1990s in Europe

Dose-Response relationships

DRs

Ozone metric


Feb 18-19 2016

Ozone characterization indices

0

20

40

60

80

100

0 50 100 150 200 250 300 350

Year day

Ozo

ne

co

nc (

pp

b)

0

2000

4000

6000

8000

10000

12000

AO

T4

0 (

pp

b.h

rs)

Growing season

M7: 7 hour growing season mean AOT40: Accumulated Over Threshold 40 ppb

M12: 12 hour growing season mean

SUM06: Accumulated Over 60 ppb

W126: Weibull weighted O3 concentration

NCLAN / EOTC :

Ozone Metrics

M7

AOT40


Feb 18-19 2016

Showed fairly substantial effect of ‘foreign sourced’ O3 on crop yields…causing

between 5 to 35 % of the O3 induced crop yield loss.

HTAP1 - By necessity, assessment used ‘Concentration’ based

indices....

O3 Yield

loss by

region


Feb 18-19 2016

M7 AOT40

soybean more sensitive than

spring wheat

Spring wheat more sensitive

than soybean

…in part due to problems with concentration based indices

Uncertainty in the ranking of species sensitivity

Source attribution of the ozone found at a rural location in

southern England during 2006 (Derwent, 2008).

Year

AOT40

Using AOT40 (or a high threshold) the level of ‘domestic’ pollution needs to be

relatively high for imported pollution to have an effect on vegetation

…in part due to problems with concentration based indices


Feb 18-19 2016


Feb 18-19 2016

KM2: Concentration-based indices to assess the importance of O3

damage, especially those which use thresholds (e.g. AOT40) may not be

appropriate for assessment of damage resulting from ICT. O3 flux

metrics (e.g. PODy) that incorporate the effects of differences in

phenology and environmental conditions in estimates of O3 damage are

more suitable for assessments of the potential impact of ICT.

Stomatal O3 flux

Hourly stomatal O3 flux

above ‘y’ (Fsty) Non-stomatal

flux/uptake/deposition

External plant

surfaces

Soil

Species, cultivar,

Phenology,

Environmental

variables (e.g.

irradiance,

temperature, VPD,

Soil water status,

CO2 concentration)


Feb 18-19 2016


Feb 18-19 2016

PODy AOT40 W126 24hr

This more ‘biologically meaningful’ ozone metric can therefore be used to

understand the characteristics of O3 profiles most likely to cause damage

O3 flux incorporates a wider range of O3 concentrations in the

accumulation of the index

y

Hourly O3 flux >’y’ (Fsty) accumulates to form PODy

Source attribution of the ozone found at a rural location in

southern England during 2006 (Derwent, 2008).

…benefit of flux based indices

Year

y

Earlier and later in the season imported pollution is also likely to have a

greater influence on local vegetation

PODy


Feb 18-19 2016

Fst

y

[email protected]

e.g. Monthly mean stomatal O3 flux (Fsty) decreases over crop

receptor regions for combined 20% emission reductions

HTAP, Potsdam, Germany

Feb 18-19 2016

Fst

y


Feb 18-19 2016

Could ‘flux’ also help assess the significance across the globe of different

emission reduction policies (e.g. global CH4 vs local/regional NOx/VOC

reductions)

Mills et al, in prep

O3 profiles (magnitude & frequency of O3 conc.) change over

time and by region as a result of emission reductions – as PODy


Feb 18-19 2016

Other benefits of using the ‘flux’ approach

Already included in CTM modelling schemes as part of the O3

deposition module :o)….but lots of differences in these schemes :o(

Stomatal conductance a determinant of gas exchange (O3 and CO2)

and therefore plant C assimilation and growth – links to crop

growth models (AgMIP)

Stomatal Ozone

Flux - PODy


Feb 18-19 2016

What are the main differences in O3 dry deposition

schemes?

Wesely (1989) Pleim et al (2001) DO3SE (2003)

Surface

resistance terms

Stomatal, plant cuticle, in

canopy (buoyancy,

density, upper & lower

canopies) ground surface


canopy, (empirical),

ground surface, LAI


canopy, (empirical), ground

surface, LAI

Stomatal

resistance

Multiplicative

Solar radiation, surface

air temperature

Photosynthesis

Species type, growing

season, photosynthetically

active radiation, surface air

temperature, vapour

pressure deficit, soil

moisture content

Multiplicative or

Photosynthesis

Species type, growing season,

photosynthetically active

radiation, surface air

temperature, vapour pressure

deficit, soil moisture content

Landcover

parameterisation

North America (?)

7 vegetation types and 5

seasonal categories (e.g.

Agricultural land -

Midsummer with lush

vegetation)

North America

25 vegetation types

European (& some Asian)

10 deposition cover types plus

>15 O3 sensitive target species

for effects estimates (with

climate region

parameterisations)


Feb 18-19 2016

Variation in O3 deposition estimates by 17 different global Chemistry

Transport Models

Hardacre et al. 2015


Feb 18-19 2016


schemes?


Surface

resistance terms


canopy (buoyancy,





ground surface, LAI



surface, LAI

Stomatal

resistance

Multiplicative


air temperature

Photosynthesis




temperature, vapour


moisture content

Multiplicative or

Photosynthesis






Landcover

parameterisation

(LAI)

North America (?)



Agricultural land -

Midsummer with lush

vegetation)

North America

25 vegetation types





climate region

parameterisations)


Feb 18-19 2016

Variability in O3 dry deposition partitioned to land cover

Total annual O3 dry deposition Annual average O3 Vg

Hardacre et al. 2015


Feb 18-19 2016


schemes?


Surface

resistance terms


canopy (buoyancy,





ground surface, LAI



surface, LAI

Stomatal

resistance

Multiplicative


air temperature

Photosynthesis




temperature, vapour


moisture content

Multiplicative or

Photosynthesis






Landcover

parameterisation

North America (?)



Agricultural land -

Midsummer with lush

vegetation)

North America

25 vegetation types





climate region

parameterisations)

Growing season defined by

effective temperature sum

Two gsto algorithms:

Multiplicative

(Jarvis; Emberson, 2000 etc..)

Photosynthesis-based

(Farquhar, 1980 & Leuning, 1990)

Stomatal resistance (Rsto)

gsto = gmax [min(fphen, fO3)] * flight * max {fmin, (ftemp * fVPD * fSWP)}

𝒈𝒔𝒕𝒐 = 𝒈𝒔𝒕𝒐.𝟎 +𝒎.𝑨𝒏𝒆𝒕. 𝒉𝒔𝒄𝒔


Feb 18-19 2016

Stomatal Ozone

Flux - PODy

Soil water and influence on gsto

modelled using Penman-Monteith


Feb 18-19 2016

Other benefits of using the ‘flux’ approach

Already included in CTM modelling schemes as part of the O3

deposition module :o)….but lots of differences in these schemes :o(

Stomatal Ozone

Flux - PODy

Stomatal flux determines gas exchange (i.e. O3 as well as CO2) and

therefore photosynthesis, plant C assimilation, growth and yield….

…..links to crop growth models (AgMIP) AND can allow inclusion of

other stressors (e.g. water availability, soil fertility (N fertilizer),

[aerosol], [CO2], climate….


Feb 18-19 2016

Development of DO3SE coupled Photosynthesis-stomatal

conductance (An-gsto) model ….

Integrating effects of O3, N, H2O, CO2 and climate

• Coupled An-gsto model (based on Farquhar et al. 1980 and Ball-Berry.

1987)

• Maximum rate of photosynthesis (An) determined by maximum

carboxylation efficiency (Vcmax) – which is species-specific

• …but with species-specific Vcmax altered by Leaf N

• ….and damaged by O3 (based on Martin et al. 1992)

gsto

CO2 supply

O3 uptake

H2O loss

A CO2 demand

Ci, Cs

An Vcmax

R

fO3 Leaf N

Damage e.g. biomass loss/

yield loss / reduction

in C sequestration

N deposition

[email protected]

HTAP2 output ‘request’ for flux

HTAP, Potsdam, Germany

Feb 18-19 2016

• total O3 flux (Ftot),

• O3 dry deposition velocity (Vg),

• Stomatal O3 flux (Fsty),

• O3 concentration at canopy height [O3_ch],

• Leaf level stomatal conductance (gsto_leaf),

• canopy stomatal conductance (Gsto),

• leaf area index (LAI), etc...,


Feb 18-19 2016

• Which is the most appropriate metric to determine vegetation

impacts? Stomatal O3 flux (Fsty) to give PODy

• What is the influence of the metrics threshold (i.e. ‘y’ threshold and

phenology) on the importance of ‘foreign’ vs ‘domestically’ sourced

O3?

• What influence do domestic vs foreign emissions have on O3

vegetation impacts - Can we develop S-R relationships for PODy?

• What are the most effective future emission mitigation strategies for

vegetation; how will these vary ‘regionally’ and ‘into the future’?

(global CH4 or local/regional NOx/VOCs)

HTAP2 Qs for ecosystems

Vegetation Impacts from Air Pollution focus on O3 · [email protected] HTAP, Potsdam, Germany...

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