No.8

Introduction
Data Policy
Data
Documentation
Contact Information



Giordan Lighthouse

-CO-

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Observation
Category : Air sampling observation
Situation : ongoing
Time zone : Local time +1


Sampling
Sampling height : 7
Description : continuous
Sampling and analysis frequency : Continuous at ambient pressure
Sampling environment : When the prevailing wind is from the South East (120 - 140), the air parcels are affected by local anthropogenic activities. Therefore CO concentrations are more pronounced.

When the wind direction is from the North sector (300 - 20) the air parcels are affected by ships emissions.
Description for sampling analysis : PTFE intake 4.5 m long with an internal diameter 0.04 m. Intake height: 7 metres above ground. The intake is connected to a glass manifold approximately 1.40 meters long. The manifold consists eight nipples to feed trace gases instruments. The flow rate through the complete inlet is supported by a blower. Ambient air is supplied to the analysers via 6mm PTFE tube connected between the manifold and the inlet of the analyser. The analyser is assigned with a 5 micron filter which is changed every two weeks.


Instrument and Analysis
Measurement method : Cavity Ring-Down Spectroscopy (CRDS)
Current status and history of instrument : The Picarro analyser (model G2401) uses CRDS technology and measures four gases simutaniously: carbon monoxide (CO), carbon dioxide (CO2), methane (CH4) and water (H2O).
Description of instrument : LDL: 2 ppb
Max Drift: 50 ppb per month
Max Uncertainty: < 2 ppb
Operating range: 0 - 5 ppm
Measuring interval: < 5 seconds


Calibration
Current scale employed in the measurement : traceable to national standard scale
Measurement calibration : N/A
Scale and calibration(treasability) :


Data Processing
Measurement unit : ppb
Data processing : The web logger is polling the instrument every 10 seconds and stores the data as 1 minute averages.
Processing for averaging :

Data flag :
Data remarks :


Other Information
Scientific aim :
Reference :


submitted by University of Malta

The WDCGG is operated by the Japan Meteorological Agency
in collaboration with the World Meteorological Organization