Letter report preparexl for the Technical Steering Panel and the Centers for Disease Control and Prevention under Contract 200-92-0503 (CDC)/18620 (BNV0 Battelle Pacific Northwest Laboratories Richland, Washington 99352 tDI,6TRtl_ITION OF THIS DOCUMENT IS UNLIMITED No experimental evidence indicates that either of these alternatives would improve the ability of RATCHET to estimate the transport of radionuclides released to the atmosphere from Hanford operations. vi Glossary Acronym/Term Definition AFB Air Force Base B and T Separationplant designations BNW Battelle, Pacific Northwest Laboratories Cartesian Refers to a coordinate system in which positions are expressed by distances from the axes, as opposed to polar and sphericalcoordinates, which use angles as well as distances. " CDC Centersfor Disease Control and Prevention CIDER Calculations of IndividualDoses from EnvironmentalRadionuclides Coriolis force An apparentforce, due to the earth's rotation, that causes moving air to deviate to the right in the northernhemisphere DESCARTES Dynamic EStimates of ConcentrationsAnd Radionuclides in Terrestrial EnvironmentS DOE Departmentof Energy Ekman spiral Theoreticalvariationof wind speed and direction with heightunder a very restrictiveset of assumptions Froude number A nondimensionai numberexpressing the ratio between inertial and gravitational forces FY Fiscal year HEDR HanfordEnvironmentalDose Reconstruction HEDRIC HEDR IntegratedCode _2. _ HMS Hanford Meteorological Station Monin-Obukhovlength A scaling length for atmosphericturbulencein the surface layer defined by the heat flux and a scaling velocity called the friction velocity Monte Carlo A mathematical method of estimating outputdistributionswhen model input is uncertain