Major Step Forward in detecting Nuclear Explosions
CTBTO-WMO cooperation Enhances nuclear test-ban verification
Geneva/Vienna 1 September 2008 - The ability to detect the location of possible nuclear explosions will be significantly
enhanced following the provisional entry into operation today (September 1st, 2008) of a joint response system of the
Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) and the World Meteorological
Organization (WMO).
By applying a technique called Atmospheric Transport Modelling (ATM), the three-dimensional travel path of a
radionuclide particle is backtracked from where it was detected by a monitoring station, to the area where it may have
originated. This process is called source region attribution. Similar methods, although less sophisticated than those
employed today, were already used in April 1986 by Swedish experts to attribute the radioactive cloud over Sweden to the
Chernobyl reactor catastrophe – even before it became public.
Through the input of WMO’s high-quality global meteorological data, the CTBTO will be able to considerably improve its
ATM calculations for radioactive particles detected by one of the 80 radionuclide stations of the CTBTO International
Monitoring System (IMS).
In the next step, referred to as data fusion, the results of ATM are compared to the data harvested through the other
verification technologies (the so-called waveform technologies: seismic, hydroacoustic and infrasound). The synergy of
both allows for a much more accurate location of a potential nuclear explosion. The more precisely the verification
system can determine the location of a possible nuclear explosion at this point, the greater the chances of a subsequent
on-site inspection finding concrete evidence of a recent nuclear test.
As the CTBTO-WMO response system becomes operational, the CTBTO will be able to send requests for assistance in the case
of suspicious radionuclide detections directly to nine WMO Regional Specialized Meteorological Centres/National
Meteorological Centres around the world. These centres will then submit their computations to the CTBTO as fast as is
technically feasible but within 24 hours at the latest.
Cooperation between the CTBTO and the WMO dates back to 2000 and was enshrined in an Agreement in 2003. Annual
atmospheric backtracking exercises between the CTBTO and WMO Centres take place since 2003, with the next one scheduled
to take place within the next few months. In addition, unannounced system tests will be carried out every quarter.
WMO has been involved in international efforts for monitoring of nuclear tests since the 1990s when negotiations on the
Comprehensive Nuclear-Test-Ban Treaty (CTBT) within the UN Conference on Disarmament were still ongoing. By offering the
use of its Global Telecommunications System for data exchange, WMO enabled the experts to make great advances toward
designing what later became the model for the current IMS.
ENDS