Simulation of Cs-137 through RTOFS_EP_WPA, after the
Fukushima-Daichii nuclear accident.
A numerical simulation for the time evolution of the 3-dimensional Cs-137
concentration after the Fukushima-Daichii nuclear plant accident was
performed, and is referred as RTOFS_EP_WPA (RTOFS
Episodic Tracer for
the Western Pacific).
The simulation uses the HYCOM model, in the domain 134°E-30°W,
1/12° horizontal resolution, with 32 vertical layers, nested to the
daily nowcast archives of the
Global RTOFS model,
a global operational ocean
prediction model at EMC, in strong partnership with the Navy). The
regional simulation is run in forecast mode (with no data assimilation
inside the domain). The HYCOM source is version 2.2.36tr, with
atmospheric deposition of tracers.
Cs-137 is added as an atmospheric deposition to the top layer of the
ocean model, with the horizontal and time evolution provided by NOAA's
HYSPLIT-NSC (V.3) for Cs-137, based on Cs-137 source by Japan's Nuclear
Safety Commission's. HYSPLIT-NSC covers the whole period of deposition,
March 12-April 21, 2011, with a total deposition of 5.4 PBq over the
ocean (1 PBq=1015 Becquerels).
At model day April 26 2011, the direct ocean discharge of Cs-137 from
waters released from the plant was added as simulated by NOS' ROMS
coastal model (Lanerole, Patchen, et al, 2012 Ocean Sciences meeting,
Salt Lake City), normalized to 4.5 PB of total direct discharge.
The 3-D Cs-137 concentration is followed in a simulation to estimate the
importance of patches in the Pacific Ocean.
Results from the simulation were presented in:
Tolman, H., Z. Garraffo, A. Mehra, I. Rivin, H-C Kim, T. Spindler, 2012:
"Ocean plume and tracer modeling for the Fukushima-Dai'ichi event",
2012 Ocean Sciences meeting, Salt Lake City.
Garraffo Z.D, H-C. Kim, A. Mehra, T. Spindler, H. Tolman, 2012: "Tracer
modeling with the Hybrid Coordinates Ocean Model (HYCOM)", 2012 Ocean
Sciences meeting, Salt Lake City.