In line with the GAW Data Policy, users should contact the contributors of all data of interest and propose co-authorship or acknowledgement.
Organization
| NO | 7 |
|---|---|
| Acronym | ANSTO |
| Name | Australian Nuclear Science and Technology Organisation |
| Address 1 | Locked Bag 2001 |
| Address 2 | Kirrawee DC, NSW 2232 |
| Address 3 | Australia |
| Country/Territory | Australia |
| Website | http://www.ansto.gov.au/ |
Contact(s)
| Name | Alastair Williams |
|---|---|
| Prefix | Dr. |
| agw@ansto.gov.au | |
| Organization No | 7 |
| Organization acronym | ANSTO |
| Organization name | Australian Nuclear Science and Technology Organisation |
| Organization country/territory | Australia |
| Address 1 | ANSTO, Locked Bag 2001 |
| Address 2 | Kirrawee DC, NSW 2232 |
| Address 3 | Australia |
| Country/territory | Australia |
| Tel | +61 2 9717 3694 |
| Fax | |
| Last updated date | 2020-06-10 |
| Name | Scott Chambers |
|---|---|
| Prefix | Dr. |
| szc@ansto.gov.au | |
| Organization No | 7 |
| Organization acronym | ANSTO |
| Organization name | Australian Nuclear Science and Technology Organisation |
| Organization country/territory | Australia |
| Address 1 | ANSTO, Locked Bag 2001 |
| Address 2 | Kirrawee DC, NSW 2232 |
| Address 3 | Australia |
| Country/territory | Australia |
| Tel | +61 2 9717 3058 |
| Fax | |
| Last updated date | 2020-06-10 |
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| Atmospheric tracer | |||||||||||||
| UTC+10:00 | |||||||||||||
| mBq/m3 | |||||||||||||
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9999-12-31 00:00:00 - 9999-12-31 23:59:59: Unknown |
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9999-12-31 00:00:00 - 9999-12-31 23:59:59: 5000L and 1500L(Unknown) |
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9999-12-31 00:00:00 - 9999-12-31 23:59:59: 70 (m) |
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The detector is calibrated by injecting radon from a Pylon calibration source (22.6 +/- 4% kBq 226Ra before Feb 2016, replaced by 102.186 +/- 4% kBq 226Ra after Feb 2016; traceable to NIST standards) at ~80 cc/min for a period of 4-6 hours. Ambient radon counts at the time of the calibration peak are estimated by linearly interpolating the ambient values between the start and end points of the calibration injection (a period of 8 - 10 hours). This procedure is most reliable when air mass fetch over the calibration period is oceanic. The net peak count is then determined by removing the ambient count rate from the peak calibration count rate. The net peak count is then converted to a value in counts per second. The radon concentration in the tank at the time of peak counts is then estimated as a ratio of the source radon delivery rate (2.847 Bq/min 222Rn before Feb 2016, replaced by 12.8754 Bq/min 222Rn after Feb 2016) and the sample flow rate (300 L/min). A calibration factor (counts per second, per Bq/m3) is then determined as the ratio of the net peak counts per second and the radon concentration in the detector. This calibration factor is scaled up by 7% to account for the fact that the radon concentration in the detector would not have fully come to equilibrium within the 4-6 hour injection period. The raw 30 minute detector counts are aggregated to hourly values, the instrumental background is removed, and then the calibration factor is applied to derive hourly radon concentrations in mBq m-3. |
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Prior to removing instrumental background counts and calibrating to concentrations, the 30 min raw data are checked for spiking (usually electrical noise) or periods of instrument malfunction. These periods, as well as calibration and instrumental background check periods are set to a value of -999.999 in the data stream. Specific notes: (1) Radon concentrations have been adjusted to compensate for the effects of a slow leak into the common input line of both detectors, discovered and fixed on 14/9/2018. As it started off very slowly, the leak only become noticeable in the data gradually over a period of several months. As a result of the leak, (adjusted) radon concentrations close to and below baseline values should be treated with caution from 1/1/2017 up to 14/9/2018. (2) Radon concentrations have been corrected for a systematic calibration error discovered on the May 2017 field trip to Cape Grim. The error resulted in previously calculated radon concentrations (at least back to the start of 1992) from the primary detector being too small by a factor of exactly 1.128. (3) Note that 2013 contains an 8 month period (1/2/13 - 30/9/13) when the primary detector (HURD3) was operating abnormally. This period has been "patched out" and replaced with data from the backup detector. (4) This dataset supersedes all previous versions. Data between 1987-1991 is not included, as it has reduced accuracy, contains unknown errors and should only be used under guidance (see contacts listed). |
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[Hourly] Hourly data are aggregates of 30-minute counts and calibrated as described above. All periods of invalid data are shown as -999.999 in the data stream. If one 30-minute sample of the hour is bad/missing, the whole hour is set to -999.999. Missing/invalid data periods from the primary detector are "patched" with good data from the backup detector, in order to achieve a final integrated data stream which has very few missing data points. No other averaging is performed. All final reported hourly 222Rn concentrations are in mBq m-3. [Daily] [Monthly] |
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| There is no data quality flag. Bad/missing data points are indicated by -999.999 in the data stream. | |||||||||||||
| Operational/Reporting | |||||||||||||
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- Continuous hourly atmospheric 222Rn concentrations are measured directly (i.e. not via ambient progeny measurements) at Cape Grim using two dual flow loop, two filter radon detectors: a 5000L'primary' detector and a 1500L 'backup' detector. - Time series have not been shifted to account for sensor response and delay times (total shift recommended: 60min). - No STP corrections have been applied. The principal of operation for ANSTO-built dual flow loop two filter detectors is described in Whittlestone and Zahorowski (1998), Chambers et al. (2011) and Williams and Chambers (2015). It is important to note that the performance characteristics of the detectors have changed markedly over the period of this data set (1987 - present), with earlier detectors having lower sensitivities, higher LLDs ('lower limit of detection') and longer response times (see details in Williams and Chambers, 2015). The current instrument response time (time to reach half-peak magnitude) is 45 minutes. To account for the response time, and the sample delay, a lag of 1 hour is recommended compared to simultaneously observed parameters. The current primary detector's 'lower limit of detection' (defined here to be the radon concentration at which the counting error first exceeds 30%) is approximately 30 mBq m-3. The detector's observation range spans 5 orders of magnitude. Assuming a Poisson process for 222Rn activity, the median standard deviation of ambient hourly counts is 6% of the reported concentration (influenced by the fact that ambient concentrations are not necessarily constant over the hour). Instrumental background counts (primarily due to the accumulation of long-lived 210Pb on the detectors second filter) are characterised every 3 months. The background (modelled linearly with time) is removed from the raw counts prior to calibration. Typically, the standard deviation of a background measurement is equivalent to about 5 mBq m-3. Consequently, when ambient radon concentrations fall well below the detection limit, very small negative concentrations can sometimes be reported. The 5000L 'primary' and 1500L 'backup' radon detectors, designed and built by the Australian Nuclear Science and Technology Organisation (ANSTO), are situated against a wall outside the northeast corner of the Cape Grim station, where they are relatively sheltered from large diurnal temperature fluctuations and buffeting winds. Sample air is drawn from 70m agl on the sampling tower through 50mm copper pipe using a stack blower (Becker, SV 8.130/1-01). Protection at the air inlet has been fitted to minimise the ingestion of precipitation. Between the stack blower and the primary detector the sample air is ducted through 19mm copper pipe. The total length of the inlet line provides sufficient time to reduce any ambient 220Rn (thoron, half-life 55.6s) concentrations to negligible levels. The sample exhaust valve of the detector is left slightly constricted such that, with the stack blower upstream of the detector, the portion of the inlet pipe close to the surface, as well as the detector itself, are always maintained at a slight positive pressure compared to ambient (around +100 Pa). This minimises the likelihood of near-surface air (high in 222Rn and 220Rn) entering the sampling stream should any small leaks develop over time. |
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Wind direction: Wind speed: Relative humidity: Precipitation amount: Air pressure: Air temperature: Dew point temperature: Sea water temperature: Sea surface water temperature: Sea water salinity: Sea surface water salinity: |
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Meteorological data may remain as first provided, even when greenhouse gas data are updated. |
No DOI available
Related information
| Format | Text (WDCGG Data Format Table, WDCGG Meteorological Data Format Table), NetCDF | ||||
|---|---|---|---|---|---|
| Relation List (Is Part Of) |
All 222Rn data contributed to WDCGG by GAW stations and mobiles by 2023-08-16 All 222Rn data contributed to WDCGG by GAW stations and mobiles by 2022-07-11 All 222Rn data contributed to WDCGG by GAW stations and mobiles by 2021-02-22 All 222Rn data contributed to WDCGG by GAW stations and mobiles by 2020-06-19 All 222Rn data contributed to WDCGG by GAW stations and mobiles by 2019-03-07 All 222Rn data contributed to WDCGG by GAW stations and mobiles by 2018-06-08 |
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GAW Data Policy
"For Scientific purposes, access to these data is unlimited and provided without charge.
By their use you accept that an offer of co-authorship will be made through personal contact with the data providers
or owners whenever substantial use is made of their data.
In all cases, an acknowledgement must be made to the data providers or owners and to the data centre when these data are used within a publication."
Citation format
This format is an example of the WDCGG standard citation.
Please follow the citation format which the data providers or owners indicate.
Please follow the citation format which the data providers or owners indicate.
Alastair Williams (ANSTO),
Scott Chambers (ANSTO),
Atmospheric 222Rn
at Kennaook / Cape Grim by Australian Nuclear Science and Technology Organisation
,
dataset published as 222Rn_CGO_
surface-insitu_ANSTO_data1 at WDCGG,
ver. 2023-07-19-1826 (Reference date*: YYYY/MM/DD)
* As the reference date, please indicate the date you downloaded the files.
* As the reference date, please indicate the date you downloaded the files.
Reference(s)
| 1 | Chambers S, Williams AG, Zahorowski W, Griffiths A, Crawford J (2011) Separating remote fetch and local mixing influences on vertical radon measurements in the lower atmosphere. Tellus 63B:843-859 |
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| 2 | Whittlestone S. and Zahorowski W (1998) Baseline radon detectors for shipboard use: development and deployment in the first Aerosol Characterization Experiment (ACE 1). J. Geophys. Res. 103, 16743-16751. |
| 3 | Zahorowski W., Griffiths AD, et al (2013) Constraining annual and seasonal radon-222 flux density from the Southern Ocean using radon-222 concentrations in the boundary layer at Cape Grim, Tellus B, 65, 19622, http://dx.doi.org/10.3402/tellusb.v65i0.19622 |
| 4 | Williams, AG, and Chambers, SD, 2016: ‘A history of radon measurements at Cape Grim’, Baseline Atmospheric Program (Australia) History and Recollections (40th Anniversary Special Edition), 131-146. |
