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Bukit Koto Tabang
-O3-
| Observation |
| Category |
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Air sampling observation |
| Situation |
: |
ongoing |
| Time zone |
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Local time 7 |
| Sampling |
| Sampling height |
: |
4.5 |
| Description |
: |
continuous |
| Sampling and analysis frequency |
: |
Continuous, 1-minute aggregates (since 2006), 10-minute aggregates (2001-2005), 1-hour aggregates (until 2000) |
| Sampling environment |
: |
The station is located in the middle of tropical rain forest. Local sources of ozone precursors include biomass burning from domestic and subsistence farming activities. The site is influenced by biomass burning in East Sumatra. |
| Description for sampling analysis |
: |
Surface ozone measurements were initiated at Bukit Koto Tabang in 1996 by Mick Meyer from CSIRO. The set-up, consisting of a TEI49 (S/N 49-51974-290) and a TEI49PS (S/N 49PS-52307-291) instrument, both fully automated and controlled by a custom-built unit, is
described elsewhere [Meyer et al., 1998].
The measurements were interrupted between August 1999 and July 2001 due to a complete failure of the control and data acquisition unit. This unit was replaced by QA/SAC Switzerland and WCC-Empa in July 2001 [Zellweger et al., 2001]. Further, the inlet line was significantly shortened, and a modified refrigerator was installed to lower the dew point of sample air going through the instrument. No significant ozone loss was found over the inlet line and filter, but the refrigerator caused an average ozone loss of 0.8%. The instrument has been in operation in this configuration continuously since then. In September 2006, a TEI49C (S/N 49C-58547-318) instrument was provided to the station. This instrument has higher resolution and is less noisy than the TEI49. It shares the inlet with the TEI49 and has served as the main instrument since its installation. |
| Instrument and Analysis |
| Measurement method |
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Light absorption analysis (UV) |
| Current status and history of instrument |
: |
see above |
| Description of instrument |
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Thermo Environmental Instruments Inc. , USA
TEI49 (S/N49-51974-290) since 1996
TEI49C (S/N 49C-58547-318) since 09/2006 |
| Calibration |
| Current scale employed in the measurement |
: |
WMO/GAW (SRP) |
| Measurement calibration |
: |
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| Scale and calibration(treasability) |
: |
Measurements are traceable to SRP#2. The traceability chain consists of periodic inter-comparisons of SRP#2 with SRP#15, internal consistency checks of SRP#15 against several other SRPs, calibration of a transfer standard instrument (TEI 49C PS), and transfer of the scale to the field instrument about every 2 years. On site, inter-comparisons between the field instrument(s) and a TEI 49 PS are conducted every 2 months. |
| Data Processing |
| Measurement unit |
: |
ppb |
| Data processing |
: |
Raw data were 10-minute averages provided from the instrument internal data logger. These data were visually inspected, invalid data were flagged, and a zero- and span-corrected data set was computed based on the TEI49-TS-(SRP) inter-comparisons conducted by WCC-Empa. |
| Processing for averaging |
: |
Processing for Hourly Data:
Average of 10-minute values. No criterion for minimum data-availability was applied.
Processing for Daily Data:
Average of 1-hourly values. No criterion for minimum data-availability was applied.
Processing for Monthly Data:
Average of daily values. No criterion for minimum data-availability was applied. |
| Data flag |
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No classification of data was performed. |
| Data remarks |
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The column 'REM' indicates the estimated combined standard uncertainty of 1-hourly values, computed according to Klausen et al. (2003). |
| Other Information |
| Scientific aim |
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Assessment of Air quality, background concentrations, long-range transport of air pollutants, climate change, source apportionment |
| Reference |
: |
http://gaw.empa.ch/gawsis
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| submitted by Agency for Meteorology, Climatology and Geophysics / Swiss Federal Laboratories for Materials Testing and Research |
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