Assessment of potential atmospheric transport and deposition patterns due to Russian Pacific Fleet operations.

A probabilistic analysis of atmospheric transport and deposition patterns from two nuclear risk sites-Kamchatka and Vladivostok-situated in the Russian Far East to countries and geographical regions of interest (Japan, China, North and South Koreas, territories of the Russian Far East, State of Alaska, and Aleutian Chain Islands, US) was performed. The main questions addressed were the following: Which geographical territories are at the highest risk from hypothetical releases at these sites? What are the probabilities for radionuclide atmospheric transport and deposition on different neighboring countries in case of accidents at the sites? For analysis, several research tools developed within the Arctic Risk Project were applied: (1) isentropic trajectory model to calculate a multiyear dataset of 5-day forward trajectories that originated over the site locations at various altitudes; (2) DERMA long-range transport model to simulate 5-day atmospheric transport, dispersion, and deposition of 137Cs for 1-day release (at the rate of 10(10) Bq/s); and (3) a set of statistical methods (including exploratory, cluster, and probability fields analyses) for evaluation of trajectory and dispersion modeling results. The possible impact (on annual, seasonal, and monthly basis) of selected risk sites on neighboring geographical regions is evaluated using a set of various indicators. For trajectory modeling, the indicators examined are: (1) atmospheric transport pathways, (2) airflow probability fields, (3) fast transport probability fields, (4) maximum possible impact zone, (5) maximum reaching distance, and (6) typical transport time fields. For dispersion modeling, the indicators examined are: (1) time integrated air concentration, (2) dry deposition, and (3) wet deposition. It was found for both sites that within the boundary layer the westerly flows are dominant throughout the year (more than 60% of the time), increasing with altitude of free troposphere up to 85% of the time. For the Kamchatka site, the US regions are at the highest risk with the average times of atmospheric transport ranging from 3 to 5.1 days and depositions of 10(-1) Bq/m2 and lower. For the Vladivostok site, the northern China and Japan regions are at the highest risk with the average times of atmospheric transport of 0.5 and 1.6 days, respectively, and depositions ranging from 10(0) to 10(+2) Bq/m2. The areas of maximum potentially impacted zones are 30 x 10(4) km2 and 25 x 10(4) km2 for the Kamchatka and Vladivostok sites, respectively.

Can the confidence in long range atmospheric transport models be increased? The pan-european experience of ensemble.

Is atmospheric dispersion forecasting an important asset of the early-phase nuclear emergency response management? Is there a 'perfect atmospheric dispersion model'? Is there a way to make the results of dispersion models more reliable and trustworthy? While seeking to answer these questions the multi-model ensemble dispersion forecast system ENSEMBLE will be presented.

Airborne transmission of foot-and-mouth disease virus from Burnside Farm, Heddon-on-the-Wall, Northumberland, during the 2001 epidemic in the United Kingdom.

The results of a detailed assessment of the atmospheric conditions when foot-and-mouth disease (FMD) virus was released from Burnside Farm, Heddon-on-the-Wall, Northumberland at the start of the 2001 epidemic in the UK are consistent with the hypothesis that the disease was spread to seven of the 12 farms in the immediate vicinity of the source by airborne virus, and airborne infection could not be ruled out for three other premises; the remaining two premises were unlikely to have been infected by airborne virus. The distances involved ranged from less than 1 km up to 9 km. One of the farms which was most probably infected by airborne virus from Burnside Farm was Prestwick Hall Farm, which is believed to have been key to the rapid spread of the disease throughout the country. In contrast, the results of detailed atmospheric modelling, based on a combination of clinical evidence from the field and laboratory experiments have shown that by assuming a relationship between the 24-hour average virus concentrations and subsequent infection, threshold infection levels were seldom reached at the farms close to Burnside Farm. However, significant short-term fluctuations in the concentration of virus can occur, and short-lived high concentrations may have increased the probability of infection and explain this discrepancy.

An integrated model to predict the atmospheric spread of foot-and-mouth disease virus.

The application of a computer model called Rimpuff for simulating the airborne spread of foot-and-mouth disease (FMD) is described. Rimpuff is more sophisticated and accurate than other FMD simulation models previously described. It can be run on a desktop computer and performs analyses very quickly. It can be linked to a geographical information system and so the information generated can be integrated with geographical and demographical data for display in a format that can be easily assimilated and transmitted electronically. The system was validated using historical data from outbreaks of FMD in France and the UK in 1981, and from Denmark and the former German Democratic Republic (GDR) in 1982. A very good fit was obtained between the direction of the plumes of virus simulated by the model and the spread of disease from France to the UK in 1981. Although cattle in the UK were infected during the episode, the concentrations of airborne virus in the plumes simulated by the model were beneath the infectivity threshold for cattle. It was concluded from the analysis that the number of pigs infected in France, and therefore the source concentration of airborne virus, was probably much higher than was recorded at the time of the outbreaks. Analysis of the Denmark/GDR episode pointed to the possibility that the source of virus for the 1982 epidemic in Denmark could have been one or more unreported outbreaks involving pigs in the former GDR.

Decision-making uncertainties in emergency warning system organizations

The record of organizational decision making in warning systems is systematically reviewed. A descriptive model of organizational decision-making points and linkages is proposed. The review of 39 historical accounts included in this work led to identification of four broad classes, comprised of 19 specific categories, of uncertainties in organizational decision making in organizations with warning system tasks. The major decision-making uncertainty classes identified in this review were: 1) ability to interpret the impending event; 2) communications; 3) perceived impacts of the warning and 4) exogenous influences. Primary problems have been recognition of the hazardous event and physical ability to communicate information with others in the chain of warning dissemination. It is concluded that decision-making uncertainty, at all levels and stages of warning systems, has been a major constraint to warning effectiveness and would well be a prime object to be mitigated by future warning system preparedness activities