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Ushuaia
-CO-
| Observation |
| Category |
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Air sampling observation |
| Situation |
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ongoing |
| Time zone |
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UTC |
| Sampling |
| Sampling height |
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17 |
| Description |
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continuous |
| Sampling and analysis frequency |
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Continuous
Average time: 1 minute
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| Sampling environment |
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The Ushuaia GAW Station is located roughly 10 km south-west of the city of Ushuaia on the “Isla Grande de la Tierra del Fuego”, Argentina (54° 51' S – 68° 17' W).
The station is located in a coastal cliff at an altitude of 18 m above sea level, on a remote sub-Antarctic marine coast. Steady winds blow prevailing from the clean air sector (SW) down the Beagle Channel. The ground in the vicinity around the station is covered with pasture and bush.
The vegetation in the surrounding area is consisting mainly of shrub and southern beech (Nothofagus species) forest.
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| Description for sampling analysis |
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Sampling and Analyses Intake height: 6 meters above the ground on the top of the station building.
Inlet/Manifold: From there connections to the CO instruments by PFA tubing, approximate length 6 m to the instrument.
Total flow rate: 1.5 liter per minute. The residence time is less than 5 seconds.
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| Instrument and Analysis |
| Measurement method |
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NDIR |
| Current status and history of instrument |
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Two TEI48 (Thermo Environmental Instruments Inc.) NDIR monitors were used as in-situ CO analysers. Since Dec. 1994 – To Nov. 2008.
Cross flow modulation NDIR instrument HORIBA model APMA-360. (#712020) Since Nov. 2008 - ongoing.
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| Description of instrument |
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Horiba model APMA 360
Ranges: 0 - 100 ppm
Lower detection limit: 0.05 ppm
Average time: 1 minute
Zero: -3
Span: 1.0320
Operation Temperature: 5-40°C
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| Calibration |
| Current scale employed in the measurement |
: |
WMO-2000 |
| Measurement calibration |
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Automatic Zero check is performed daily (From 17:00 UTC to 17:40 UTC). It uses a separate zero-air unit (silica gel drying cartridges followed by a pump followed by Purafil and Sofnocat.
Automatic Span check is performed daily (From 17:40 UTC to 18:00 UTC) using a dilution unit combined with high concentration carbon monoxide standard and the zero air. The standards were assigned with WMO-2000 traceable carbon monoxide mole fractions by WCC-Empa.
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| Scale and calibration(treasability) |
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The data refer to the WCC CO standard.
System and performance audit conducted by WMO - IFU November 1994.
System and performance audit conducted by WMO - EMPA November 1998.
System and performance audit conducted by WMO - EMPA November 2003.
System and performance audit conducted by WMO - EMPA November 2008.
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| Data Processing |
| Measurement unit |
: |
ppb |
| Data processing |
: |
The raw data from instrument is collected by the data acquisition system, and stored every one minute. CO measurements are checked at the site by an operator every day. All irregular measurements and information are recorded in a log book.
Invalid data caused by instrumental malfunction or other effects are checked by comparison/correlation with other trace substances and meteorological data or with information from the station logbook and then are rejected.
Meteorological data, statistical methods and information from the logbook are used to flag the one minute raw data.
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| Processing for averaging |
: |
Processing for Hourly Data:
Hourly data take the arithmetic mean of respective one minute mean validated data with the number of valid data more than 40.
(2/3 rule)
Processing for Daily Data:
Daily data take the arithmetic mean of respective hourly data with the number of valid hourly data more than 15.
(2/3 rule)
Processing for Monthly Data:
Monthly data take the arithmetic mean of respective hourly data with the number of hourly data more than 480.
(2/3 rule) |
| Data flag |
: |
Flag 0: Valid data (Baseline Conditions)
Flag 1: Valid data (Non Baseline Conditions-Data affected by pollution)
Flag 2: Non valid or missing data.
We defined as Baseline or Background conditions:
Wind direction within 90°- 270°
Wind speed >= 3m/s
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| Data remarks |
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| Other Information |
| Scientific aim |
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To provide data for research to reveal long term trends of air pollution and long distance transport in mid-latitudes of the southern hemisphere. |
| Reference |
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| submitted by National Weather Service |
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