value of chamber based n o in developing national … regional emissions estimates with a novel...

Generating Regional Emissions Estimates with a Novel Hierarchy of Observations and UpscaledSimulation Experiments (GREENHOUSE)

The value of chamber based N2O measurements in developing national scale inventories

Bob Rees, Mark Lee, Sylvia Toet, Pete Levy, Nick Cowan, Ben Keane, Kairsty Topp, Rob Clement, Emanuel Blei, Mat Williams

Understanding the European Greenhouse Gas Budget: Towards supporting COP21 Royal Society, London 8‐9th March 2017 1

Nitrous oxide emission measurements;Not for the faint hearted!

• Highly variable in time and space

• Emissions associated with two different source processes

• Peak emissions driven by a coincidence of driving variables

• Annual emissions dominated by a small number of emission peaks

• Measurement technology is limiting

2Understanding the European Greenhouse Gas Budget: Towards supporting COP21

Measurement scales

Static manual chamber

Static chamber

Skyline

Eddy covariance

Tall towers

Aircraft

Earth observation


Site Description

4

Chamber technique

5

Sample collection(field)

Analysis(laboratory)

Flux calculation

AdvantagesLow cost, spatially referenced, widely deployed

DisadvantagesLow spatial and temporal coverage, inconsistencies in application of method

Understanding the European Greenhouse Gas Budget: Towards supporting COP21

Chambers

-50.0

0.0

50.0

100.0

150.0

200.0

250.0

300.0

350.0

07-Mar 26-Apr 15-Jun 04-Aug 23-Sep 12-Nov 01-Jan 20-Feb 10-Apr 30-May

Dai

ly m

ean

N2O

flux

(g N

2O-N

ha-

1d-

1 )

Daily mean N2O flux (g N2O-N ha-1 d-1)

Control AN 80 kg N/ha AN 160 kg N/haAN 240 kg N/ha AN 320 kg N/ha AN 400 kg N/haAN inc. NI 320 kg N/ha Urea 320 kg N/ha Urea inc. NI 320 kg N/ha

6

Bell et al, 2016

Understanding the European Greenhouse Gas Budget: Towards supporting COP21

Characterise heterogeneity


Explore relationships between emissions and driving variables

• Nitrous oxide emissions vary significantly in time and space

• Chamber type measurements allow us to explore fine scale relationships with driving variables

0

10

20

30

40

50

60

70

-20 -10 0 10 20 30 40 50 60 70 80

WFP

S (%

)

N2O-N g ha-1 d-1

Hinton et al 2015 8Understanding the European Greenhouse Gas Budget: Towards supporting COP21

Allow us to establish relative change

Treatment 1 Treatment 2 Treatment 3

N2O

‐N kg N ha‐

1 y‐1

9Understanding the European Greenhouse Gas Budget: Towards supporting COP21 Rees et al, 2016

‐20

30

80

130

180

230

280

01‐Apr‐2012 21‐May‐2012 10‐Jul‐2012 29‐Aug‐2012 18‐Oct‐2012 07‐Dec‐2012 26‐Jan‐2013 17‐Mar‐2013

Daily m

ean N2O

flux

(g N

2O‐N ha‐

1d‐

1 )

synthetic urine

urine

dung

control

urine+DCD

Spring experiment

Spring Summer Autumn

Characterising emissions from contrasting N sources

10Bell et al, 2016 Understanding the European Greenhouse Gas Budget: Towards supporting COP21

Measurement inter‐comparisons

• Different measurement techniques work at different spatial and temporal scales

• However inter‐comparisons provide some confidence in the application of different approaches


Upscaling

Field observations

Empirical relationships

Process based modelling

Top down constraints

Validation


Conclusions

• Field measurements of nitrous oxide and (therefore) modelling remains challenging

• Different measurement an modelling approaches are both complimentary and essential to allow an understanding of process (fine scale) to be linked to national and regional scale estimates


Thanks

• NERC, Scottish Government• Crichton Dairy Research Centre

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value of chamber based n o in developing national … regional emissions estimates with a novel...

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