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 Organization

NO 23
Acronym Empa
Name Swiss Federal Laboratories for Materials Science and Technology
Address 1 Ueberlandstrasse 129
Address 2 8600 Duebendorf
Address 3 Switzerland
Country/Territory Switzerland
Website http://www.empa.ch/gaw

 Contact(s)

Name Thomas Seitz
Prefix Dr.
Email thomas.seitz@empa.ch
Organization No 23
Organization acronym Empa
Organization name Swiss Federal Laboratories for Materials Science and Technology
Organization country/territory Switzerland
Address 1
Address 2
Address 3 Überlandstrasse 129 CH-8600 Dübendorf Switzerland
Country/territory Switzerland
Tel +41 58 765 4655
Fax
Last updated date 2020-07-09


Name Martin Steinbacher
Prefix Dr.
Email martin.steinbacher@empa.ch
Organization No 23
Organization acronym Empa
Organization name Swiss Federal Laboratories for Materials Science and Technology
Organization country/territory Switzerland
Address 1 Ueberlandstrasse 129
Address 2 CH-8600 Duebendorf
Address 3 Switzerland
Country/territory Switzerland
Tel +41 58 765 4048
Fax +41 58 765 1122
Last updated date 2020-08-28


 Background observation
 UTC+01:00
 ppb
 1991-01-01 00:00:00 - 1999-09-30 23:59:59: NIST SRM 1677c
 1999-10-01 00:00:00 - 2000-12-31 23:59:59: NMI PRM AC11
 2001-01-01 00:00:00 - 2006-04-30 23:59:59: NIST SRM 1677c
 2006-05-01 00:00:00 - 2011-11-30 23:59:59: NIST SRM 2612a
 2011-12-01 00:00:00 - 2011-12-31 23:59:59: NPL PRGM in synth. Air
 2012-01-01 00:00:00 - 2012-12-31 23:59:59: WMO CO X2000
 2013-01-01 00:00:00 - 2015-12-31 23:59:59: WMO CO X2004
 2016-01-01 00:00:00 - 9999-12-31 23:59:59: WMO CO X2014A
 1996-01-01 00:00:00 - 2007-06-05 18:59:59: HORIBA Ltd. APMA 360(NDIR)
 2007-06-05 19:00:00 - 2011-05-10 12:59:59: HORIBA Ltd. APMA 370(NDIR)
 2011-05-10 13:00:00 - 2011-12-31 23:59:59: HORIBA Ltd. APMA 360(NDIR)
 2012-01-01 00:00:00 - 9999-12-31 23:59:59: Picarro G2401(CRDS)
 9999-12-31 00:00:00 - 9999-12-31 23:59:59: 10 (m)
 5 seconds
 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
3 December 2016: Calibration frequency was reduced to one a week but calibration sequence is not run 4 times in a row to identify/eliminate effects in the pressure regulators while sample refers stagnant for several days. Two target tanks are connected to timely identify instrumental or calibration issues.
Scale and Calibration (traceability) : 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:
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 (reference gases are analyzed by WCC-Empa)
2013-2015 data are reported on the WMO-2004 scale (reference gases are analyzed by WCC-Empa)
since December 2015: reference gases are prepared and analyzed by ICOS Central Calibration Laboratory in Jena, Germany; gases are fully traceable to WMO-2014A.
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.
 For Horiba analyzers: data availability required for calculation of averages: >= 75% of 10-minute values;
for Picarro Inc. analyzers, the expanded measurement uncertainty in the nominal values of the reference gases is estimated to be::
U_CO = 2 x [(0.42 nmol mol-1)^2 + (0.0061*c)^2]^(1/2)
with c = CO mole fraction in nmol mol-1.
Standard deviation of repeated target tank measurements is < 2 ppb
 [Hourly] 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:
From 2016 onwards: number of detections refers to the number of available 5-second averages within the respective hour; data are discarded when less than 240 5-second averages are available for the respective hour
 [Daily] 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:
From 2016 onwards: number of detections refers to the number of available 1-min averages within the respective day
From 2018 onwards: number of detections refers to the number of available hourly averages within the respective day
 [Monthly] From 2016 onwards: number of detections refers to the number of available 1-min averages within the respective month
From 2018 onwards: number of detections refers to the number of available daily averages within the respective month
 
 Operational/Reporting
 Sampling Environment : measurements in pristine air, usually negligible local sources. Surfaces are mostly covered by snow or ice apart from some steep slopes of bare rock. No vegetation or soil present in the vicinity.
Description of Instruments : From 1 January 2012 to to 01 November 2017 the sample air was dried prior to analysis by means of a Nafion dryer. Along with CO, the instrument is also capable to measure H2O. Thus, the CO data can be corrected for interferences of remaining water traces.
Since 01 November 2017, no sample drying is applied anymore and CO dry air mixing ratios are determined by application of an empirical humidity correction to the fully unaltered humid gas stream accounting for dilution and pressure broadening effects.
Description of Instruments : 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)
From 1 January 2012 to to 01 November 2017 the sample air was dried prior to analysis by means of a Nafion dryer. Along with CO, the instrument is also capable to measure H2O. Thus, the CO data can be corrected for interferences of remaining water traces.
From 01 November 2017 until 25 October 2019, no sample drying is applied and CO dry air mixing ratios are determined by application of an empirical humidity correction to the fully unaltered humid gas stream accounting for dilution and pressure broadening effects. Since 25 October 2015, the sample air is again dried prior to analysis by means of a Nafion dryer.
Horiba instruments: non-dispersive infrared detection (NDIR)
Picarro instrument: Cavity Ring Down Spectroscopy CRDS
 Wind direction: 1
 Wind speed: 1
 Relative humidity: 1
 Precipitation amount: 0
 Air pressure: 1
 Air temperature: 1
 Dew point temperature: 0
 Sea water temperature: 0
 Sea surface water temperature: 0
 Sea water salinity: 0
 Sea surface water salinity: 0
Meteorological data may remain as first provded, even when greenhouse gas data are updated.
 Meteorological data at Jungfraujoch are measured by MeteoSwiss as part of its operation of the SwissMetNet Network.
see www.meteoswiss.admin.ch/
and
Appenzeller et al., Monitoring climate at Jungfraujoch in the high Swiss Alpine region, Science of The Total Environment, 391 (2–3), 262-268, https://doi.org/10.1016/j.scitotenv.2007.10.005
for more information.
1  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.
2  see
Zellweger C., M. Steinbacher, B. Buchmann, 2012 - Evaluation of new laser spectrometer techniques for in-situ carbon monoxide measurements. Atmospheric Measurement Techniques, 5, 2555-2567.
for an assessment of the CRDS technique for continuous monitoring.