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Jungfraujoch
-CO-
| Observation |
| Category |
: |
Air sampling observation |
| Situation |
: |
ongoing |
| Time zone |
: |
Local time +1 |
| Sampling |
| Sampling height |
: |
|
| Description |
: |
continuous |
| Sampling and analysis frequency |
: |
Continuous |
| Sampling environment |
: |
measurements in pristine air, usually negligible local sources |
| Description for sampling analysis |
: |
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| Instrument and Analysis |
| Measurement method |
: |
Horiba instruments: non-dispersive infrared detection (NDIR)
Picarro instrument: Cavity Ring Down Spectroscopy CRDS |
| Current status and history of instrument |
: |
non-dispersive infrared detection (NDIR)
Cavity Ring Down Spectroscopy CRDS |
| Description of instrument |
: |
HORIBA Ltd. APMA 360 (till 05 June 2007)
HORIBA Ltd. APMA 370 (till 10 Mai 2011)
HORIBA Ltd. APMA 360 (till 1 January 2012)
Picarro Inc. CO/CO2/CH4/H2O G2401 (since 1 January 2012) |
| Calibration |
| Current scale employed in the measurement |
: |
for HORIBA Ltd. analyzers:
NIST SRM 2612a (10ppm ± 0.12ppm); consistent with WMO-2000
for Picarro Inc. analyzer:
multi-point calibration with compressed real-air that are scaled against NOAA certified cylinders by WCC-Empa.
2012 data are reported on the WMO-2000 scale
2013 data are reported on the WMO-2004 scale |
| Measurement calibration |
: |
for HORIBA Ltd. analyzers:
Automatic zero-check is performed every 49 hours (no automatic span-check). Manual calibration is performed every two-three weeks. Concentrations are referred to NIST standards and are confirmed with CMDL cylinders #CA02859 (194.7ppb) and #CA02854 (295.5 ppb).
for Picarro Inc. analyzer:
multi-point calibration with two (after December 2012 three) reference gases and CO-free zero gas is performed every 45 hours; a target tank is measured every 15 hours for quality control
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| Scale and calibration(treasability) |
: |
for HORIBA Ltd. analyzers:
From 1996 until 10/1999: NIST SRM 1677c (10ppm ± 0.05ppm);
from 10/1999 until 01/2001: NMI PRM AC11 (10ppm ± 0.08ppm);
from 01/2001 until 05/2006: NIST SRM 1677c(10ppm ± 0.05ppm);
from 05/2006 to 12/2011: NIST SRM 2612a (10ppm ± 0.12ppm); consistent with WMO-2000;
since 12/2011: NPL PRGM in synth. air (10ppm ± 0.04ppm); NPL is traceable to NIST (refer to the NPL homepage)
for Picarro Inc. analyzer:
2012 data are reported on the WMO-2000 scale (reference gases are analyzed by WCC-Empa)
2013 data are reported on the WMO-2004 scale reference gases are analyzed by WCC-Empa)
The NDIR analyzer ran next to the CRDS analyzer until April 2014 for quality control and to ensure a smooth transition when changing the measurement technique.
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| Data Processing |
| Measurement unit |
: |
ppb |
| Data processing |
: |
Data availability required for calculation of averages: >= 75% of 10-minute values; |
| Processing for averaging |
: |
Processing for Hourly Data:
for HORIBA Ltd. analyzers:
Estimated standard uncertainty for hourly averages is 2.4 ppbv for values below 120 ppbv; 2 % for values greater than 120 ppbv.
since 1 January 2008: equation for estimated standard uncertainty for daily averages is given below.
for Picarro Inc. analyzers:
5-sec averages are processed (i.e. application of humidity correction, calibration function etc.) and aggregated to 1-min, 10-min, hourly, daily and monthly averages
Processing for Daily Data:
for HORIBA Ltd. analyzers:
Estimated standard uncertainty for daily averages:
[2008-01-01 thru 2009-01-01] uncertainty = [(0.0141ppm)^2+(0.0125*c)^2]^0.5;
[2009-01-01 thru 2010-01-01]: uncertainty = [(0.0191ppm)^2+(0.0070*c)^2]^0.5;
[2010-01-01 thru 2012-01-01]: uncertainty = [(0.0208ppm)^2+(0.0069*c)^2]^0.5
for Picarro Inc. analyzers: to be determined
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| Data flag |
: |
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| Data remarks |
: |
SD: If the SD is listed: Instead of the SD (standard deviation), the standard uncertainty is given.
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| Other Information |
| Scientific aim |
: |
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| Reference |
: |
see
Zellweger C., Hueglin C., Klausen J., Steinbacher M., Vollmer M. K., Buchmann B., 2009. Inter-comparison of four different carbon monoxide measurements techniques and evaluation of the long-term carbon monoxide time series of Jungfraujoch. Atmospheric Chemistry and Physics 9, 3491-3503.
for an analysis of the CO time series and an evaluation of the NDIR technique at Jungfraujoch. |
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| submitted by Swiss Federal Laboratories for Materials Testing and Research |
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