Naslov
An airflow over the Dinaric Alps simulated with a modified mixing-length formulation in WRF model

Autori
Grisogono, Branko ; Milovac, Josipa ; Telišman Prtenjak, Maja ; Bašić, Tomislav

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
31st International Conference on Alpine Meteorology / - , 2011

Skup
31st International Conference on Alpine Meteorology

Mjesto i datum
Aviemore, Ujedinjeno Kraljevstvo, 23.05.2011. - 27.05.2011

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
PBL; turbulence

Sažetak
Numerical meteorological forecasting models still do not possess a sufficient accuracy to perform hour-to-hour and site-to-site reliable weather prognosis, say, within a standard deviation of a forecasted and later on observed parameter at a given site. One of the reasons that the models miss certain parts of airflow evolution is in inadequate model parameterizations of subgrid scale processes, such as mixing due to stratified turbulence. This parameterization issue is even more present in cases of coastal mountain airflows where various air masses interact over different underlying surfaces and over complex terrain. A generalized so-called ‘z-less‘‘ mixing length- scale is deployed in WRF simulating the airflow over the NE Adriatic coast for a few days of June 2008. This length-scale is uniformly valid for stably-stratified airflows while taking an explicit care of existing local turbulence, mean wind-shear, buoyancy and turbulent Prandtl number ; i.e., the length-scale formulation is valid and monotonic for all positive gradient Richardson numbers, Ri, Ri ≥ 0 while also including local values of Prandtl number. The related simulation is compared to its counterpart using a standard WRF parameterization suite and to the regular near-surface and air-sounding data observed in the area. The airflow studied pertains to a moderate bora flow that is locally and occasionally interrupted or overtaken by diurnal circulations. The preliminary results show that the simulation with the new generalized mixing length-scale provides a generally wider range of variability for the important meteorological variables, such as e.g., the near-surface wind. Almost needless to say, sufficient spatio-temporal variability of the modeled fields has been often missing in outputs from majority of numerical meteorological models. This case study contributes to modeling sub- mesoscale details of airflow over complex terrain.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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