3.3 Meteorology and atmospheric dispersion A system integrated comprehensive atmospheric dispersion module has been built from models suitable for fast real-time atmospheric dispersion calculations as suggested by [1], cf. Table 1. TABLE 1: THE MET-RODOS MODULE: Associated models and data Near-range flow and dispersion models, including pre-processors: · Meteorological pre-processor (PAD) · Mass Consistent Flow model (MCF) · Linearized flow model (LINCOM) · Puff model with gamma dose (RIMPUFF) · Near-range elongated puff model (ATSTEP) Complex terrain models (stand alone system): · Prognostic flow model (ADREA) and Lagrangian dispersion model (DIPCOT) Mesoscale and Long-range Models: · Hybrid Lagrangian-Eulerian model (MATCH) On-line Weather Forecast data: · Numerical Weather Prediction data (DMI-HIRLAM and SPA -TYPHOON) The module is called MET-RODOS and it consists of models and pre-processors contributed to by Work Group 2 (Atmospheric Dispersion) partners. 3.3.1 The MET-RODOS module A schematic overview of the system integrated MET-RODOS atmospheric dispersion module [2] is presented in Figure 1. Details about the systems „functionality specification“ is described in [3] whereas the systems User’s manual [4] holds references to the systems User’s guides, input/output specifications and test runs. The MET-RODOS dispersion module contains three distinguishable sub-systems: • The Local-Scale Pre-processor LSP, • The Local-Scale Model Chain LSMC, and • The long-range Model Chain LRMC 57 On-site Off-site N So dar ’ s Met- +4 Hr Towers W Real -time P ON-LINE MET-DATA INTERFACE & STORAGE Long- S u* x PAD SUB’ Range Local Scale z/L x Model x I O I Zi Chain Pre-processor A,B,C x I O M Models MCF & LINCOM provides A RO DO S Wind & Turbulence grid fields over: T 10Co 15Co C 20Co Topograph Roughness Thermal H Shared RODOS INTEGRATED DISPERSION MODULES: ATSTEP RIM PUFF Memory Figure 1.: (a) The MET-RODOS system integrated within RODOS MET-RODOS: Atmospheric Dispersion Model Chains Input - Output and Model Chains Meteorological on-line data: Release and site Input: On-line: On-line: Met-towers, SODAR, specific data Source Local (on-site) Met- Numerical Weather Prog’s from NWP centers Topography terms towers and Sodars Prediction data Local Scale Preprocessor LSP Pre-processors for Met-towers, SODAR’s, NWP data Model Chains: Turbulence parameterisation schemes Local Scale Preprocessor <LSP> Local Scale Model Chain <LSMC> Diagnostic wind model Mass consistent wind LINCOM model MCF Long Range Model Chain <LRMC> Atmospheric Dispersion Models Output: Local scale models: Long-range model: Doses from Cloud and Trajectories and RIMPUFFand ATSTEP MATCH Deposition Weather Forecasts (b) MET-RODOS Atmospheric Dispersion Model Chains. (c) MET-RODOS input/output and model chain structure. MET-RODOS has its own build-in Local Scale Pre-processor software called LSP, cf. Figure 1a. 58 LSP [5] provides the local-scale Atmospheric Dispersion Models (ADM’s) with measured and forecasted local scale wind fields and dispersion parameters. It provides local scale diffusion and atmospheric deposition parameters as well as local scale wind fields for plume and puff transport. It integrates local scale wind models with micro-meteorological pre-processing algorithms. LSMC, the local scale model chain [6], contains a suite of different local scale mean wind and dispersion models, Via LSMC, different wind and dispersion models can be activated depending on the character of the topography and atmospheric stability in question. LSMC and provides via its build-in ADM‘s ground level air concentrations (in [Bq/m3]) and concentration of deposited isotopes (in [Bq/m2]), and ground level gamma dose rates (in Grays per second [Gy/s]) for subsequent use by the RODOS system. When clouds are leaving the outer bounds of the local scale domain (variable from 20 km to 160 km), diffusion specific parameters such as cloud size, content and position is passed on to the long-range model chain LRMC. LRMC, the long-range model chain, manages the transport and fallout assessments on national and European scales in MET-RODOS. Near surface air concentrations (in [Bq/m3]) and integrated depositions of isotopes (in [Bq/m2]) are provided, Inputs are in the first place weather data from any numerical weather prediction system, like the DMI-HIRLAM, which gives a consistent description of the atmospheric state and motion on a synoptic scale. Secondly dispersion inputs are taken from the LRMC in terms of source information given as cloud puffs defined by location, size and mass content. The MET-RODOS module is furthermore integrated with the RODOS systems real-data bases: an on-line met-tower database and a real-time updated Numerical Weather Prediction (NWP) database. The On- line Met-Tower Data Base maintains and updates meteorological met-tower measurements available to the system, and FCASTDB is a real-time numerical weather forecast data base that stores and time stamps the real-time numerical weather forecast data available to the system. Integration within RODOS MET-RODOS is an integral part of the RODOS system. Mode and time control, data management, user input and graphics control are all handled via the RODOS Operating Subsystem (OSY). As indicated in Figure 1a, MET-RODOS communicates with the operating system via shared memory and has access to the RoGIS integrated real-time databases. MET-RODOS’ input source terms are provided directly via RODOS real-time data bases while meteorological data are downloaded in background via on-line network connection. MET-RODOS generated output (i.e. dose rates from air and ground deposited material) is stored in the ROGIS database. On-line meteorological input data Real-time application of the system requires an on-line connection to quality real-time measurements of local meteorological quantities (wind, direction, stability etc). Such data must be available from at least one nearby and on-line connected met-tower in the vicinity of the release point (on-site). For application of the system on distances beyond the local 10 (20) km) scale, on-line meteorological measurements from within the regional (100-km scale) of wind and temperature conditions can also be used by the MET-RODOS module for „now-casting“ of the plume spread in real time. The system can monitor an on-going release in real time based on met-data from a single or a network of on-line automatic meteorological stations. Real-time numerical weather prediction data 59 Forecasting of accidents in time is based on pre-calculated or downloaded numerical weather prediction data to the system. If such data are not available directly at the RODOS emergency centre, such weather forecast data can be downloaded to the system via the Internet from national or international meteorological forecasting services. Numerical weather prediction (NWP) data for Europe are today available via computer networks at high spatial and temporal resolution (8–50 km horizontal grid resolution at three (and in some cases one) hour time intervals up to typically +48 hours). High-resolution NWP data are produced around the clock at a number of national and international operational meteorological centres. During the RODOS development and implementation phase 1998–1999, NWP data have been obtained on-line from the Danish Meteorological Institute (DMI) and previously also from the SPA-Typhoon partner in Obninsk, Russia. A data delivery agreement was negotiated with the Danish meteorological institute DMI for real-time on-line deliverance of real-time on-line NWP products for the developing phase of the RODOS project. A subsequent section describes the DMI-HIRLAM model and the gained experience with the on-line data transfer and integration of DMI-HIRLAM NWP products in the MET-RODOS module. The local scale model chain LSMC The running of ATSTEP or RIMPUFF requires, in addition to the standard meteorological parameters wind and temperature, also determination of the dispersion controlling scaling parameters, such as stability category or the Monin-Obukhov stability measure, and determination of the mixing height. To serve this purpose, extensive pre-processing software has been included in the local scale model chain, [6]. On-line incoming meteorology – from either automatic meteorology stations and/or from weather forecast model nodes near or inside the local-scale model domain – are pre-processed into gridded mean (wind) and turbulence quantities (including the above mentioned atmospheric stability measures) for all local scale grid points LSP, which invokes a set of nine pre-processing routines (the so-called PAD sub-routines) is running in real-time in conjunction with the fast diagnostic local-scale and turbulence models (LINCOM). The Local Scale Model Chain LSMC also handles the local scale dispersion, deposition and gamma radiation models, and it produces „source-terms“ for the long-range model chain LRMC. Local scale pre-processor LSP Figure 1(a-c) shows the Local Scale Pre-processing unit LSP interfacing on-line accessible meteorological information from met-towers and from NWP centres to the local scale dispersion models ATSTEP and RIMPUFF and to the long-range model chain with MATCH. The LSP unit provides the necessary model input parameters for running both local and the long-range dispersion models. The starting point is parsing and binning of the (at random in time) on-line incoming meteorological data, which automatically are checked for consistency and stored in the RODOS systems real-time database. It holds separate partitions for both the on-line met-TOWER DataBase ”TOWERDB”, and the real-time numerical weather ForeCAST DataBase “FCASTDB”. Continuously running in background LSP accesses the real-time database (every 10 min) and processes all new meteorology available, including new met-tower measurements and new forecast data, into gridded wind and scaling parameters fields on the local scale grid. They are continuously stored as time-stamped grid files in the RODOS system’s shared memory.