资源环境科技发展态势分析平台

Abstract. We estimate the seasonal and diurnal changes in the transport and intensity of radionuclides including Iodine-131 (¹³¹I) and Cesium-137 (¹³⁷Cs), transported to Qatar from a fictitious accident at the Barakah nuclear power plant (B-NPP) in UAE. For dispersion modeling, we have used the Lagrangian particle/air parcel dispersion model FLEXible PARTicle (FLEXPART) driven by forecast and (re)analysis products, and coupled with the Weather Research and Forecasting model (FLEXPART-WRF). A four-member ensemble of meteorological inputs, including one forecast dataset (CFSv2) and three (re)analysis datasets (native resolution and downscaled FNL and downscaled ERA5), is used to force FLEXPART/FLEXPART-WRF. According to the age spectrum of Lagrangian particles, radionuclides entered southern Qatar about 10 to 20 hours after emission, and almost all emitted particles are transported to and/or deposited in the study area within the 80 hours after the release. A higher number of long-lived particles was found in FNL simulations and when particles are released in the afternoon and spring. The highest levels of simulated ¹³¹I concentrations and ¹³⁷Cs deposition were found in FNL simulations in the south/southeast of Qatar. The frequent coincidence of high radionuclide concentrations and deposition with particles released between 5 a.m. and 2 p.m. and in the cold period of the year was attributed to diurnal and seasonal changes in the planetary boundary layer height (PBLH) and synoptic circulations. The difference in input PBLH explains well the inter-member variations of simulated radionuclide concentrations. Simulated concentrations were found with the same level of consistency as reported for real case studies.