Spredningsmodeller land/by - oversvømmelser Brugen af højdedata i BRS og DMU 4. Oktober 2006 Dan Kampmann, Beredskabsstyrelsen Martin Hvidberg, DMU
Fra spredning over åbent land, der påvirkes af bjergkæder og ruhedsfaktorer i landskabet til byspredning, der påvirkes af mange lokale forhold: bygningshøjder, vejbredder, træer, terrænforhold mv. Spredningstyper: Luftforurening,kemiske uheld, nukleare uheld, dirty bombs, atombomber, biologiske våben. Modified from Hertel, O. 2006
Beredskabsstyrelsen anvender kortmodulet emap, der er udviklet til ARGOS-N, ARGOS-CN, ARGOS-CBRN og NucInfo (infosystem/logsystem). Der er behov for bedre højdedata for at kunne lave meningsfulde havstigningspolygoner. I mange tilfælde vil 15 cm opløsning være ok, men i flade, lavvandede områder. TV: Havstigning anvendt på DEM filer fra USA. TH: Højdekoter fra Kort10 (KMS). Højeste punkt: 8 m. Opløsning for lille til at havstigningspolygoner genereret fra nabo koter giver mening.
ARGOS-CN Byspredningsmodel (UDM) Præsentation for Beredskabskontaktudvalget
Bygningshøjder i KORT10 fra KMS BRS og DMU har måttet sande, at bygningshøjder er i forhold til havniveau. Bygninger på Bornholm bliver meget høje. BRS har fået KMS til at generere hushøjder for alle huse i Danmark relativt til vejkanter/terræn. DMU har selv genereret hushøjder i forhold til KMS terræn data. DMU har konstateret unøjagtigheder. Botanisk haves drivhus er under jordniveau. Til højre: Hushøjder fra KORT10 i området omkring Strøget. Fremover bør man ved databehandling af punktskyen lægge vægt på nøjagtige hushøjder (tagrende, DSM-DTM ), omkringliggende terræn data (DTM) samt taghøjder (fladt tag, saddeltag)
DMU Overview... DMU præsentation, Martin Hvidberg What is air pollution Where does it come from How do we model it? How it really works? What are the errors? Questions
DMU: What is air pollution? Gasses Particles Elements NOx (NO and NO2) O3 CO SO2 Coarse Medium Fine Ultra fine Pb, Hg, As, Cd, Ni, Benzen IOM
DMU: AirGIS how it really works Input address, e.g. from epidemiological studies 1. Geo coding (finding geographical coordinates) 2. Identifying the nearest, representative, street Sampling traffic information 3. Calculating Street width 4. Calculating Street AirGIS length - a black box? 5. Calculating Street direction 6. Describing the local horizon 7. Calculations in Dispersion and Chemical Process model Pollution values
DMU: AirGIS how it really works 7. Street Configuration Describing the local horizon The height of the surrounding buildings are of great importance to the pollution levels in the street canyon. Here an example from Jagtvej. The street level pollution (100%) is strongly reduced with the height. The break of the curve is at roof top height. Above this height the pollution is stable at urban background level. NOx ppb As percentage of street concentrations Reduction_background_excluded Reduction_total_incl.back. 0% -10% 0 5 10 15 20 25 30-20% -30% Building height: 18-20m -40% -50% -60% -70% -80% -90% -100% Rec Height in m modified from Ketzel, M. 2006
DMU: Why is street configuration important? The amount of pollution generated locally = f(traffic density) The volume the pollution is mixed in = f(street width, Street height) The ventilation of the street canyon = f(street width, Street height) The ventilation of the street canyon = f(street direction, Wind direction) The ventilation of the street canyon = f(the compactness of the facades) Modified from: Berkowicz, et.al. 1997
DMU: AirGIS how it really works 7. Street Configuration Describing the local horizon The height of the surrounding buildings are of great importance to the pollution levels in the street canyon. Here an example from Jagtvej. The street level pollution (100%) is strongly reduced with the height. The break of the curve is at roof top height. Above this height the pollution is stable at urban background level. NOx ppb As percentage of street concentrations Reduction_background_excluded Reduction_total_incl.back. 0% -10% 0 5 10 15 20 25 30-20% -30% Building height: 18-20m -40% -50% -60% -70% -80% -90% -100% Rec Height in m modified from Ketzel, M. 2006
DMU: AirGIS how it really works 7. Street Configuration Describing the local horizon To allow calculations for different meteorological conditions the building height is determined in 12 discrete intervals, equally distributed on either side of the street. Modified from Hertel, O. 2006 From: AirGIS
DMU: AirGIS how it really works 7. Street Configuration Describing the local horizon Estimating the height of the individual building is not trivial. One building do not always have one height. Available data and methods are either inaccurate and/or expensive. DHM: Cowi