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Monte Cimone
-CO-
| Observation |
| Category |
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Air sampling observation |
| Situation |
: |
ongoing |
| Time zone |
: |
Local time +1 |
| Sampling |
| Sampling height |
: |
7 |
| Description |
: |
continuous |
| Sampling and analysis frequency |
: |
high flux of real air (2 liter per min) continuosly flow through the sampling line and every 30 minutes a portion (50 ml per min) is splitted for 3 minutes to the gas-chromatograph sampling loop. |
| Sampling environment |
: |
Environment: Mountain peak with completly free horizon.
No local sources of contamination. No access by road.
Timberline about 300m below the measurement site. |
| Description for sampling analysis |
: |
The air is sampled by a 2m long heated intake at 7 m height above
the ground. The air intake is composed by an external (outside building) steel pipe (internally covered by Teflon) and the internal (inside building) Pyrex pipe.
A Stainless steel sampling line (lenght 10m) connects the air intake with analysers high flux sampling pump. |
| Instrument and Analysis |
| Measurement method |
: |
Gas Chromatography (FID) |
| Current status and history of instrument |
: |
measurements started on Jan 2007 with a modified version of a commercial Agilent GC6890 and are still ongoing; earlier data are not available since have been used to check system performance and validation; data are available since January 2008; |
| Description of instrument |
: |
time resolution: 1 measurement every 30 minutes;
sensitivity: generally below 0.3 ppbv
detection limit: theoretical LOQ (S/N = 5) 30 ppbv
measurements range:
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| Calibration |
| Current scale employed in the measurement |
: |
indirect link to NOAA 2004 scale |
| Measurement calibration |
: |
every 15 minutes a sample is analyzed alternating between real air and reference standard in order to correct for short time instrumental drifts. molar fraction is calculated from the ratio of the peak heights |
| Scale and calibration(treasability) |
: |
reference standard are real air pumped in Luxfer Scott Marrin cylinders and calibrated at MPI-Jena against NOAA 2004 cylinders. |
| Data Processing |
| Measurement unit |
: |
ppb |
| Data processing |
: |
reported data are single point, no average is computed; data validation is evaluated by checking the correct instrumental operation, the spread of the repeated working standard analysis; in case of anomalies, real data are flagged for a deep check and -eventually- removed form the final dataset. |
| Processing for averaging |
: |
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| Data flag |
: |
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| Data remarks |
: |
Each data submitted represent a real acquired concentration point, none of the post-acquisition averageing operation has been done. The precision of the measurements is then reported in the data file (REM column) as the relative standard deviation (expressed in percentage) of the repeated measure of the working standard performed in the same day of each real sample analysis (and is generally calculated over 48 working standard runs per day). |
| Other Information |
| Scientific aim |
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| Reference |
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| submitted by National Research Council, Institute of Atmospheric Sciences and Climate |
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