Traceability of Measurements within the Global Atmosphere Watch - - PowerPoint PPT Presentation

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Traceability of Measurements within the Global Atmosphere Watch - - PowerPoint PPT Presentation

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Federal Office of Meteorology Federal Office of Meteorology and Climatology MeteoSwiss and Climatology MeteoSwiss Traceability of Measurements within the Global Atmosphere Watch Programme: Results from the World Calibration Centre WCC-Empa

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SLIDE 1

Traceability of Measurements within the Global Atmosphere Watch Programme: Results from the World Calibration Centre WCC-Empa

Christoph Zellweger1, Martin Steinbacher1, Lukas Emmenegger1, Brigitte Buchmann2

1Empa, Laboratory for Air Pollution/Environmental Technology, Dübendorf, Switzerland 2Empa, Department Mobility, Energy and Environment, Dübendorf, Switzerland

NOAA ESRL Global Monitoring Annual Conference 2016

Federal Office of Meteorology and Climatology MeteoSwiss Federal Office of Meteorology and Climatology MeteoSwiss

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SLIDE 2

Audits by WCC-Empa from 1996 - 2016

WCC-Empa (O3, CO, CH4, CO2)

International GAW Activities of Switzerland

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

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SLIDE 3

Audits: Travelling Standards vs. Parallel Measurements

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

WCC-Empa Traveling Standard

 Only instrument comparison  Snapshot in time  Special care might influence results  Covers wider mole fraction range  Repeatability conditions  Assessment of the whole system  Longer time period  Less influence by operator  Limited to ambient mole fraction range

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SLIDE 4

Explanation for the following figures…

1700 1800 1900 2000 2100

  • 6
  • 4
  • 2

2 4 6 <NOAA04> (ppb) [CH4 - <NOAA04>] (ppb)

Picarro G2401 CFKADS-2018 12-04-18 07:04 to 12-04-18 14:01

0.97 0.99 1.01 1.03

  • 6
  • 4
  • 2

2 4 6 Slope / (-) Bias at 1900 ppb / (ppb)

DQOs for range 1700-2100 ppb

  • Intercept

= 12.4 ppb

  • Slope

= 0.993

  • Bias @ 1900 ppb

= -1.03 ppb

WCC-Empa TS

500 1500 500 1500 TS / (ppb) Station analyser / (ppb)

Range in unpolluted troposphere Extended compatibility goal Compatibility goal

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

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SLIDE 5

Explanation for the following figures…

1700 1800 1900 2000 2100

  • 6
  • 4
  • 2

2 4 6 <NOAA04> (ppb) [CH4 - <NOAA04>] (ppb)

Picarro G2401 CFKADS-2018 12-04-18 07:04 to 12-04-18 14:01

0.97 0.99 1.01 1.03

  • 6
  • 4
  • 2

2 4 6 Slope / (-) Bias at 1900 ppb / (ppb)

DQOs for range 1700-2100 ppb

  • Intercept

= 12.4 ppb

  • Slope

= 0.993

  • Bias @ 1900 ppb

= -1.03 ppb

WCC-Empa TS

500 1500 500 1500 TS / (ppb) Station analyser / (ppb)

Range in unpolluted troposphere Extended compatibility goal Compatibility goal

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

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SLIDE 6

Explanation for the following figures…

1700 1800 1900 2000 2100

  • 6
  • 4
  • 2

2 4 6 <NOAA04> (ppb) [CH4 - <NOAA04>] (ppb)

Picarro G2401 CFKADS-2018 12-04-18 07:04 to 12-04-18 14:01

0.97 0.99 1.01 1.03

  • 6
  • 4
  • 2

2 4 6 Slope / (-) Bias at 1900 ppb / (ppb)

DQOs for range 1700-2100 ppb

  • Intercept

= 12.4 ppb

  • Slope

= 0.993

  • Bias @ 1900 ppb

= -1.03 ppb

WCC-Empa TS

500 1500 500 1500 TS / (ppb) Station analyser / (ppb)

Range in unpolluted troposphere Extended compatibility goal Compatibility goal

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

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SLIDE 7

GHG: Relationship performance – analytical technique

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

  • Results for GHGs were recently published:
  • C. Zellweger et al., Assessment of recent advances in measurement techniques for atmospheric carbon dioxide and

methane observations, Atmos. Meas. Tech. Discuss., 2016, 1-30, 2016.

CH4 CO2

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SLIDE 8

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

  • Ozone: >50 % of the comparisons were within 1 ppb
  • ver the range 0-100 ppb.
  • Almost all measurements are done using UV

absorption technique.

  • Cases with lager deviations usually either due to

inappropriate calibration or instrument faults.

CO O3

  • CO remains challenging, although significant improvement is
  • bserved when newer techniques are used

RG: Relationship performance – analytical technique

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SLIDE 9

9

Parallel Measurements for CO at Ushuaia

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

  • Station instrument: HORIBA APMA-360
  • Travelling instrument: Picarro G2401 without sample air drying
  • From 2016-02-05 to 2016-05-10
  • Travelling instrument used independent inlet lines to same sampling location
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SLIDE 10

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

Ushuaia – HORIBA APMA-360

  • Reason for bias?
  • Difference in calibration scale? – not confirmed by

performance audit results

  • Remaining bias due to water vapor correction of the

Picarro G2401 instrument?

  • Instrumental issues of the HORIBA APMA-360 instrument,

e.g. pressure dependence leading to inappropriate zero correction.

200 400 600 800

  • 40
  • 20

20 40 <WMO-X2014> (ppb) [CO - <WMO-X2014>] (ppb)

HORIBA APMA-360 SN 712020 16-02-05 03:56 to 16-02-05 15:26

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SLIDE 11

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

Ushuaia – HORIBA APMA-360

  • Reason for bias?
  • Difference in calibration scale? – not confirmed by

performance audit results

  • Remaining bias due to water vapor correction of the

Picarro G2401 instrument?

  • Instrumental issues of the HORIBA APMA-360 instrument,

e.g. pressure dependence leading to inappropriate zero correction.

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SLIDE 12

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

Ushuaia – HORIBA APMA-360

  • Reason for bias?
  • Difference in calibration scale? – not confirmed by

performance audit results

  • Remaining bias due to water vapor correction of the

Picarro G2401 instrument?

  • Instrumental issues of the HORIBA APMA-360 instrument,

e.g. pressure dependence leading to inappropriate zero correction.

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SLIDE 13

13

Cape Point: Picarro G2302

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

  • Station instrument: Picarro G2302
  • Travelling instrument: Picarro G2401 without sample air drying
  • From 2015-10-22 to 2016-02-24
  • Travelling instrument used independent inlet lines to same sampling location and occasionally sampled from CPT inlet after drier
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SLIDE 14

100 150 200 250

  • 10
  • 5

5 10 <WMO-X2014> (ppb) [CO - <WMO-X2014>] (ppb)

Picarro G2302 #835-CKADS2026 15-11-03 00:00 to 15-11-28 16:00

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

Cape Point – Picarro G2302

  • Very good agreement for the first two months of the

comparison, in agreement to performance audit results.

  • However, a difference between the two inlets was
  • bserved. The travelling instrument Picarro G2401 was

recording higher mole fractions when sampling dry air from the Cape Point inlet.

  • This is in line with a potential influence of water vapor on

CO that was observed for this particular instrument.

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SLIDE 15

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

Cape Point – Picarro G2302

  • Very good agreement for the first two months of the

comparison, in agreement to performance audit results.

  • However, a difference between the two inlets was
  • bserved. The travelling instrument Picarro G2401 was

recording higher mole fractions when sampling dry air from the Cape Point inlet.

  • This is in line with a potential influence of water vapor on

CO that was observed for this particular instrument.

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SLIDE 16

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

Cape Point – Picarro G2302

  • Very good agreement for the first two months of the

comparison, in agreement to performance audit results.

  • However, a difference between the two inlets was
  • bserved. The travelling instrument Picarro G2401 was

recording higher mole fractions when sampling dry air from the Cape Point inlet.

  • This is in line with a potential influence of water vapor on

CO that was observed for this particular instrument.

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SLIDE 17

17

Jungfraujoch: Los Gatos LGR-23r

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

  • Station instruments: Los Gatos LGR-23r (and Picarro G2401)
  • Travelling instrument: Picarro G2401 without sample air drying
  • From 2015-03-19 to 2015-05-29
  • Travelling instrument used independent inlet lines to same sampling location plus additional inlet at a different location
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SLIDE 18

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

Jungfraujoch – LGR-23r

  • Good agreement over the entire comparison period, in

agreement to performance audit results.

50 100 150 200 250 300

  • 5

5 <WMO-X2014> (ppb) [CO - <WMO-X2014>] (ppb)

LGR-23r #12-0066 15-03-17 23:37 to 15-03-18 02:56

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SLIDE 19

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

Jungfraujoch – LGR-23r

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SLIDE 20

20

Advantage of Parallel Measurements

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

  • A significant influence of the

tourists and/or other emissions can be occasionally observed during calm days.

Both instruments sample from station inlet on top of the building WCC instruments samples from the AGAGE inlet below the tourist platform Both instruments sample from station inlet on top of the building 1-min data

GAW/NABEL inlet AGAGE inlet

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SLIDE 21

21

Advantage of Parallel Measurements

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

  • A significant influence of the

tourists and/or other emissions can be occasionally observed during calm days.

Both instruments sample from station inlet on top of the building WCC instruments samples from the AGAGE inlet below the tourist platform Both instruments sample from station inlet on top of the building 1-min data

GAW/NABEL inlet AGAGE inlet

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SLIDE 22

22

Advantage of Parallel Measurements

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

  • A significant influence of the

tourists and/or other emissions can be occasionally observed during calm days.

Both instruments sample from station inlet on top of the building WCC instruments samples from the AGAGE inlet below the tourist platform Both instruments sample from station inlet on top of the building 1-min data

GAW/NABEL inlet AGAGE inlet

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SLIDE 23

Conclusions

  • Audit approach with parallel measurements AND standard

comparisons is optimal.

  • Audit results confirm advantages of more recent measurement

techniques in the case of CO.

  • Calibration scale issues are likely to contribute to the observed

difference; however, this explains only a small part of the

  • bserved bias in many cases.
  • Recent progress made in the calibration scale (WMO-X2014A)

will further improve compatibility of measurements.

  • Ozone: Basically only one measurement technique in contrast to
  • ther species.
  • An improvement was observed over the past few year thanks to

slightly better instruments and probably also as a result of QA/QC activities.

  • Relatively good agreement of is based on instrument

comparisons only.

  • Maybe it would also be desirable to have parallel ozone

measurements during audits and other QA/QC activities.

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016

CO O3

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SLIDE 24

Thank you!

Acknowledgments

  • Financial support by MeteoSwiss
  • Staff at various GAW stations for their support

NOAA ESRL Global Monitoring Annual Conference 2016, May 17-18, 2016