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Ushuaia
-O3-
| 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 |
| Sampling environment |
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The Ushuaia 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: l meters above the ground on the top of the station building.
Inlet/Manifold: From there connections to the ozone 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.
Teflon inlet filter, exchanged monthly.
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| Instrument and Analysis |
| Measurement method |
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Light absorption analysis (UV) |
| Current status and history of instrument |
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Two TEI49 (Thermo Environmental Instruments Inc.) Since Dec. 1994 – To Nov. 2008. (#47306-278 - #47312-278).
TEI 49C (Thermo Environmental Instruments Inc.) # 58546-318 Since Nov. 2008 - ongoing.
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| Description of instrument |
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TEI 49C (Thermo Environmental Instruments Inc.)
Ranges: 0 - 200 ppm
Lower detection limit: 1.0 ppb
Average time: 1 minute
Calibration factors: Background (BKG): 0, Span: 1.012
Precision: 1 ppb
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| Calibration |
| Current scale employed in the measurement |
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GAW reference standard scale hosted by NIST SRP#15 |
| Measurement calibration |
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Automatic zero check is performed daily (From 17:00 UTC to 18:00 UTC). This zero measurement is used later for data reprocessing and correcting the ambient air measurement values.
A manual 3-points Calibration (10, 50, 100 ppb) is carried out every 4 months.
A second O3 instrument is running on-site in parallel for quality control purposes since February 2011.
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| Scale and calibration(treasability) |
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The data refer to the WCC O3 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.
Intercomparison at the Regional Calibration Centre for Surface Ozone (RCC-BsAs) by WCC-Empa in 2006 and 2010.
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| Data Processing |
| Measurement unit |
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ppb |
| Data processing |
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The raw data from instrument is collected by the data acquisition system, and stored every one minute. Ozone 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 |
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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 |
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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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