Earlier, I posted about the SIROCCO model applied to the Fukushima radiation release. Colleague Claude Estournel and her team at the University of Toulouse/CNRS have conducted an evaluation of their SIROCCO model results through April 3. The key findings are that tracer levels predicted by their model are in reasonable agreement with concentrations found at 300 m, 10 km, and 16 km offshore. Station measurements farther afield are more challenging to replicate. (See panels below from their ongoing validation effort).
The agreement with data farther offshore should improve as source term estimates are refined. Also, simulated scenarios include both a particulate and dissolved ocean release, and also airborne deposition. It’s likely that combining these scenarios would more closely mimic reality (e.g., a dissolved ocean release combined with the atmospheric deposition effects). For their simulations show airborne deposition effects dominating at longer ranges, as would be expected.
Ocean radiation levels north of the plant are reported to have risen today. This is consistent with the SIROCCO results described in the previous post. Controlled release of low-level radiation to the ocean continues.