Naslov
Mixing height computation from a numerical weather prediction model

Autori
Jeričević, Amela ; Grisogono, Branko

Vrsta, podvrsta i kategorija rada
Radovi u zbornicima skupova, cjeloviti rad (in extenso), znanstveni

Izvornik
9th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes : proceedings / Suppan, Peter - Garmisch-Partenkirchen : Forschungszentrum Karlsruhe GmbH, 2004

Skup
International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes (9 ; 2004)

Mjesto i datum
Garmisch-Partenkirchen, Njemačka, 01.06.2004. - 04.06.2004

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
dispersion models; mixing height; bulk Richardson method

Sažetak
Dispersion models require hourly values of the mixing height, H, that indicates the existence of turbulent mixing. The aim of this study was to investigate a model ability and characteristics in the prediction of H. The ALADIN, limited area numerical weather prediction (NWP) model for short-range 48-hour forecasts was used. The bulk Richardson number (RiB) method was applied to determine the height of the atmospheric boundary layer at one grid point nearest to Zagreb, Croatia. This specific location was selected because there were available radio soundings and the verification of the model could be done. Critical value of bulk Richardson number RiBc=0.3 was used. The values of H, modelled and measured, for 219 days at 12 UTC are compared, and the correlation coefficient of 0.62 is obtained. This indicates that ALADIN can be used for the calculation of H in the convective boundary layer. For the stable boundary layer (SBL), the model underestimated H systematically. Results showed that RiBc evidently increases with the increase of stability. Decoupling from the surface in the very SBL was detected, which is a consequence of the flow ease resulting in RiB becoming very large. Verification of the practical usage of the RiB method for H calculations from NWP model was performed. The necessity for including other stability parameters (e.g., surface roughness length) was evidenced. Since ALADIN model is in operational use in many European countries, this study would help the others in pre-processing NWP data for input to dispersion models.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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