CO2 measurements by means of flasks (about every two weeks) from April 1989 to December 1997. Continuous measurements of the CO2 since March 1993. Half an hour averages are available up to December 2007. Since 2008 the minimum temporal resolution for the mean values is based on hourly averages. Since 1993, ULTRAMAT 5E NDIR Analyser, SIEMENS. Since 2008 it is also working an ULTRAMAT 6E NDIR Analyser, SIEMENS. The atmospheric CO2 concentration is measured by means of a non dispersive infrared analyser (ULTRAMAT 5E and, recently, 6E) working, respectively, in the range 350-400 ppmv (5E) and 360-410 ppmv (6E). The uncertainty of the measurement is about 0.07 ppmv. The CO2 dataset of the Plateau Rosa is composed by two partially overlapped series: the first one contains weekly data measured using flasks and extends from April 1989 to December 1997; the second one contains continuous measurements, and reports data since March 1993. The atmospheric CO2 concentration is measured by means of two non dispersive infrared analysers (ULTRAMAT 5E and, recently, 6E) working, respectively, in the range 350-400 ppmv (5E) and 360-410 ppmv (6E). The CO2 measurements are referred to the WMO X2007 international mole fraction scale. The water content in the air sampling (flasks and continuous measurements) is eliminated by means of a cryogenic cooler working at -65°C. The uncertainty of the measurement is about 0.07 ppmv. Scale and Calibration (traceability): WMO X93 scale up to 2007, now WMO X2007 scale. Measurement Calibration: The CO2 analyser of Plateau Rosa is calibrated with the NOAA-CMDL primary standards. Moreover the secondary and tertiary standards (the so-called "working standard") are acquired by SIAD and referred to the primary standard. Usually the comparison among the primary and the secondary/tertiary standard is performed every six months or, at the maximum, every year. The analyzer calibration test is realized respectively every 3 days with the secondary standard and every 6 hours with the working standard. Flag: "0" means "background data" (values identified as background data by means of our criteria of selection); "1" means "not background data" (for example, due to large variability of CO2 concentration within a half an hour or values identified as not background data by means of our criteria of selection); "2" means "invalid data" (for example, instrumental problems due to the missed electrical power, incorrect calibration measurements, sampling flow incorrect and so on).

The measurement programme of the CH4 has been run by CESI RICERCA since February 1991 (at beginning by means of biweekly samplings until December 2002 and then by means of continuous measurements since January 2002). The measurements have been stopped from May 2006 to October 2007. Since 2008 the minimum temporal resolution for the mean values is based on hourly averages. Instrument: GC-FID, NIRA Venus 301 Duration of the analyses' cycle: 120 s. Detection limit: 20 ppb. The calibration measurements are realized by means of two working gas standard referred to primary standard. The working standard are systematically measured every six hours. CMDL X83 up to 2007. Since 2008 NOAA04 Scale. Convertion factor is: 1.0124. So, CMDL X83 * 1.0124 = NOAA04. In 2009, all CMDL X83 scale data have been expressed in NOAA04 scale. FLAG: "1" means "valid data". The data is considered correct but no criteria, at the moment, has been applied to identify the background data; "2" means "invalid data" (for example, instrumental problems due to the missed electrical power, incorrect calibration measurements, sampling flow incorrect and so on)

Environnement 41M up to June 2011. Starting from July 2011 by means of THERMO 49i with internal calibrator. Range of measurement: 0 – 500 ppbv. Scale and Calibration (traceability):RSE have an internal metrological lab in Milan headquarters. The primary calibrator is a Thermo Electron 49PS, calibrated by Primary Italian Metrological Institute INRIM. The analysers are periodically verified in respect of the calibrator in the scale 0-100ppbv. The procedure is agree on the ISO 9169:2006 standard. Measurement Calibration: The instrument is calibrated (up to June 2011) by means of an external ozone source (primary calibrator) when the personal is operative in situ (at least every twice months). Since July 2011 we use a THERMO 49i with internal calibration Flag: "1" means "valid data". The data is considered correct but no criteria, at the moment, has been applied to identify the background data; "2" means "invalid data" (for example, instrumental problems due to the missed electrical power, incorrect calibration measurements, sampling flow incorrect and so on).

The monitoring station of Plateau Rosa is situated in the Western Italian Alps (3480m asl). It belongs to the National Institute for Astrophysics (INAF)-Institute of Interplanetary Space Physics (IFSI), Turin Section. The measurement programme of the CO2 has been run by CESI RICERCA since April 1989 (at beginning by means of biweekly samplings until December 1997 and then by means of continuous measurements since April 1993). The atmospheric CO2 concentration is measured by means of a non-dispersive infrared analyser (ULTRAMAT 5E and, in these last years, ULTRAMAT 6E). The CO2 measurements are referred to the WMO X2007 international mole fraction scale. The CO2 atmospheric concentration is expressed in ppmv in dry air. The measurement programme of the CH4 has been run by CESI RICERCA since February 1991 (at beginning by means of biweekly samplings until December 2002 and then by means of continuous measurements since January 2002). The CH4 atmospheric concentration is expressed in ppbv and the measured method is gas chromatography by using a FID (NIRA Mod. Venus). The surface ozone measurements (O3) is available since 1989 but only in these last years have been included in a specific internal protocol and submitted to WDCGG. The ozone atmospheric concentration is expressed in ppbv and the measured method is the UV light absorption analysis by using a Environnement 41M, and recently, a Thermo 49