55 FIG. 36. Examples of calculated 137Cs depositions (Bq/m2) at three dates over the JCOPE2 domain. The average between both the KAERI and JAEA models is presented. Data correspond to integrated depositions over a three hour time interval (Japanese Standard Time (JST) is 9 hours ahead of Universal Coordinated Time (UTC)). 3.5.1.2. Direct releases to the Pacific Ocean The source term of 137Cs released directly into the ocean from the Fukushima Daiichi NPP accident was estimated as described below and in Ref. [41]. Monitoring data from the website of Tokyo Electric Power Company (TEPCO) regarding the area near to the northern and southern discharge channels of the Fukushima Daiichi NPP were used for this purpose [74]: (1) The release point was determined to be the middle point along the coast between the northern discharge channel and the southern discharge channel of the Fukushima Daiichi NPP; (2) With regard to the release duration, it was assumed that the direct release into the ocean from the Fukushima Daiichi NPP started on 26 March 2011. This was indicated by the analysis of the 131I/137Cs activity ratios [75] in ocean water. Discharges were assumed to continue until 30 June 2011;