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Halley Bay
-CO-
| Observation |
| Category |
: |
Air sampling observation |
| Situation |
: |
ongoing |
| Time zone |
: |
UTC |
| Sampling |
| Sampling height |
: |
8 |
| Description |
: |
continuous |
| Sampling and analysis frequency |
: |
Continuous 1-minute averaged data |
| Sampling environment |
: |
The concentration of CO is mainly controlled by the Hydroxyl radical (OH) concentration. Deviations occur as a result of long-range transport and local chemistry conditions.
These measurements are carried out at the Clean Air Sector laboratory at Halley research station on the Brunt ice shelf located 1100m SSE with respect to the main base.
http://www.antarctica.ac.uk/bas_research/support/labs/caslab/index.php |
| Description for sampling analysis |
: |
Sampling is taken from about 8m above the snow surface. Air intake consists of a high volume fan drawing air through an electronically polished stainless steel tube from which a sub-sample is drawn to the instrument by a stainless steel tube of 30 cm length and 1/4"diameter. The air passes through a teflon filter and a nafion dryer (PERMAPURE) before it enters the instrument. |
| Instrument and Analysis |
| Measurement method |
: |
VUV Fluorescence |
| Current status and history of instrument |
: |
The instrument (Aerolaser 5001) was manufactured in 2003 and has been running at the Halley research laboratory from July 2004 to Feb 2005 and again from Feb 2007 to Jan 2008. For the remaining years it was removed due to the research station being re-build. It was re-introduced and has run continuously from February 2012. |
| Description of instrument |
: |
Measuring range: up to 100,000.00 ppbV
Detection limit: < 0.80 ppbV at Integration time = 10 s
Sensitivity: about 30 to 100 counts/ppbV |
| Calibration |
| Current scale employed in the measurement |
: |
NOAA-GMD/WMO 2004 |
| Measurement calibration |
: |
CO is calibrated every 13 hours using a 152.9 ppbv CO (2012) in air standard cylinder which in turn is verified by the manufacturer (NOAA- GMD/WMO Central Calibration Laboratory in Boulder, Colorado, USA)every 2-3 years or when the cylinder pressure is less than 500 psi. |
| Scale and calibration(treasability) |
: |
The first standard used in the calibration of the instrument was
Cylinder CA07014 154.1 (1.0) July 2006 NOAA/WMO 2004
This was then re-calibrated in 2012
Cylinder CA07014 152.9 (1.0) July 2012 NOAA/WMO 2004 |
| Data Processing |
| Measurement unit |
: |
ppb |
| Data processing |
: |
Calibrations, zero values or any data which is invalid are omitted from data sets before averaging. Reduced quality data will be flagged appropriately.
Hourly files will be submitted in addition to daily and monthly. This data is obtained by averaging 1-minute data within a 1 hour period for example between 00:00 - 01:00. |
| Processing for averaging |
: |
Processing for Hourly Data:
1-min data are averaged to form the basis of hourly mean values.
Processing for Daily Data:
1-min data are averaged to form the basis of daily mean values.
Processing for Monthly Data:
1-min data are averaged to form the basis of monthly mean values. |
| Data flag |
: |
Error Flag = 0 Good data
Error Flag = 1 Reduced quality data
Error Flag = 2 Below detection limit
Error Flag = 3 Invalid or missing data |
| Data remarks |
: |
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| Other Information |
| Scientific aim |
: |
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| Reference |
: |
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| submitted by British Antarctic Survey |
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