 |
| Titel |
On the usability of frequency distributions and source attribution of Cs-137 detections encountered in the IMS radio-nuclide network for radionuclide event screening and climate change monitoring |
| VerfasserIn |
A. Becker, G. Wotawa, M. Zähringer |
| Konferenz |
EGU General Assembly 2009
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250025468
|
|
|
|
|
|
| Zusammenfassung |
| Under the provisions of the Comprehensive Nuclear-Test-Ban Treaty (CTBT), airborne
radioactivity is measured by means of high purity Germanium gamma ray detectors deployed
in a global monitoring network. Almost 60 of the scheduled 80 stations have been put in
provisional operations by the end of 2008. Each station daily sends the 24 hour samples’
spectroscopic data to the Vienna based Provisional Technical Secretariat (PTS) of the CTBT
Organization (CTBTO) for review for treaty-relevant nuclides. Cs-137 is one of these relevant
isotopes. Its typical minimum detectable concentration is in the order of a few μBq/m3.
However, this isotope is also known to occur in atmospheric trace concentrations, due to
known non CTBT relevant processes and sources related to, for example, the re-suspension of
cesium from historic nuclear tests and/or the Chernobyl reactor disaster, temporarily
enhanced by bio-mass burning (Wotawa et al. 2006). Properly attributed cesium
detections can be used as a proxy to detect Aeolian dust events (Igarashi et al, 2001) that
potentially carry cesium from all aforementioned sources but are also known to play
an important role for the radiative forcing in the atmosphere (shadow effect), at
the surface (albedo) and the carbon dioxide cycle when interacting with oceanic
phytoplankton (Mikami and Shi, 2005). In this context this paper provides a systematic
attribution of recent Cs-137 detections in the PTS monitoring network in order
to
Characterize those stations which are regularly affected by Cs-137
Provide input for procedures that distinguish CTBT relevant detection from other
sources (event screening)
Explore on the capability of certain stations to use their Cs-137 detections
as a proxy to detect aeolian dust events and to flag the belonging
filters to be relevant for further investigations in this field (-> EGU-2009
Session CL16/AS4.6/GM10.1: Aeolian dust: initiator, player, and recorder of
environmental change).
References
Igarashi, Y., M. Aoyama, K. Hirose,M. Takashi and S. Yabuki, 2001: Is It Possible to Use
90Sr and 137Cs As Tracers for the Aeolian Dust Transport? Water, Air, & Soil Pollution 130,
349-354.
Mikami, M. and G. Shi, 2005: Preliminary summary of aeolian dust experiment on
climate impact -Japan-Sino joint project ADEC. Geophysical Research Abstracts, 7,
05985
Wotawa, G., L.-E. De Geer, A. Becker, R.D’Amours, M. Jean, R. Servranck and K.
Ungar, 2006: Inter- and intra-continental transport of radioactive cesium released by boreal
forest fires, Geophys. Res. Lett. 33, L12806, doi: 10.1029/2006GL026206
Disclaimer
The views expressed in this publication are those of the author and do not necessarily
reflect the views of the CTBTO Preparatory Commission. |
|
|
|
|
|
|