53 surface deposition of radionuclides and radiological doses by successive use of the non- hydrostatic mesoscale meteorological prediction model MM5 and the Lagrangian particle dispersion model GEARN [70]. GEARN is a Lagrangian particle-tracking random walk model. The atmospheric dispersion of the released radionuclides is simulated by following the 3-D positions of many particles. Input data for GEARN are release condition of radionuclides and outputs from MM5 (e.g. 3-D wind fields, vertical di?usivity, mixing ratios of rain water, snow and graupel, cloud fractional cover, surface convective/non-convective precipitation and terrain height). By using 3-D and high resolution information on precipitation, GEARN can calculate deposition in detail. Output variables of GEARN are air concentration, accumulated surface deposition, air dose rate, external gamma dose and internal dose due to inhalation [71]. TABLE 15. MAIN CHARACTERISTICS OF ATMOSPHERIC DISPERSION MODELS Model Parameter WSPEEDI-II LADAS Meteorological Data Japan Meteorological Agency and MM5 Korea Meteorological Administration Domain 34–40°N, 138–145°E 34–40°N, 138–145°E Horizontal resolution 6 km × 6 km 12 km × 12 km Simulation period 2011.3.11, 23 h – 2011.5.30, 17 h (JST) 2011.3.12, 5 h – 2011.5.31, 0 h (KST) 137Cs source Ref. [70] Ref. [70] Release height 20 m, 120 m 20 m Kh Ref. [72] 2.5 × 104 m2/s Kv Mellor-Yamada level 2.5 [73] 1.0 m2/s Dry deposition velocity 0.001 m/s 0.005 m/s on forests 0.001 m/s Wet deposition scheme Sc = 5.0 × 10 ?5I0.8 I: precipitation (mm/h) Sc = 5.0 × 10?5I0.8 I: precipitation (mm/h) Output interval 3 hours 3 hours Notes: JST and KST are, respectively, Japan and Korea Standard Times. Kh and Kv are the horizontal and vertical diffusion coefficients and Sc means scavenging (s?1) Calculated deposition patterns A comparison of the time series of calculated deposition at points P1, P2 and P3 by both atmospheric dispersion models is presented in Figure 35. In general, there is a reasonable agreement between both models, which essentially produce the same deposition patterns. The main di?erences between model outputs are observed for point P2, due to the use of di?erent meteorological data, especially precipitation data, in order to simulate wet deposition. The average between both models (the ensemble) is also illustrated in Figure 35. These average values, calculated over the whole domain of JCOPE2 circulation, will be used for the realistic Fukushima simulations and integrated deposition over time intervals of three hours will be applied. As an example, average depositions over the domain for three time intervals during March are presented in Figure 36 where it can be seen that soon after the tsunami occurred the atmospheric plume is directed towards the north-east. On 16 March 2011 a significant deposition occurs inland and three days later, the plume curves towards the south, although deposition is reduced by one order of magnitude.