sebastijan mozetič, jože rakovec, nedjeljka Žagar ... · conclusions • behind any observations...
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Conclusions• Behind any observations there are errors involved in making it.• Clouds sitting on the mountain top can tell the story of winds behind and above the mountains.• Satellites are able to observe clouds with good resolutions.• Bora speeds in the valley are 2 times greater than on the slopes.• Current weather models forecast average speeds of bora but can not forecast its gusts.• Bora variation along the valley basin are not significant.
Impressions
Bora simulationsSPACE-SI in collaboration with Chair of Meteorology FMF UL has its own operational weather forecast on 3.7 km spatial resolution with WRF-ARW model (http://vreme.space.si).
A special model setup was prepared for this project, fo-cusing on the Vipava valley region and using higher resolution (1.2 km). Model forecasts have been com-pared with bora observations.
New observations
Nika: “Bora is a part of my life since the birth and I have always taken it as a self-evident fact of our lifes. The project enabled me to understand how bora develops and how we can use physics and mathematics to understand and fore-cast its occurrence.”
Mirjam: “As a child, I though bora is everywhere and I was not aware it is a specialty of our valley. The project has tought me how different factors work together to make the unique climate of the Vipava valley.”
Andraž: “I am glad that I could participate in the project. To-gether we came up with interesting findings. In addition, I also improved my knowledge of Excell.“
Model verificationComparison of model outputs and DARS stations shows that the model predicts bora occurrence, evolution and average speeds well. However, the model is not capable to represent bora gusts.
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Zemono, 10.2.2012
Model Measurements
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Ribnik, 10.2.2012Model Measurements
Model representation of the Vipava valley and surrounding orography.
We analyzed new observations from 5 instruments along two measurement lines. Horizontal distance between theinstruments is about 1.5 km. Bora measurements from 10 February 2012 illustrate the main findings:• all observations contain high-frequency variability, typical for bora (bora gusts),• along A line bora strength doubles from A01 towards A02 over 1.5 km horizontal and 100 m vertical distance,• in the valley average bora speed does not vary from one side to another.
Other stations
Locations of the DARS (Slovenian motorway company) measurement sites along the highway H4 through the Vipava valley.
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Line A, 10.2.2012A1 A2 A3
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Line B, 10.2.2012B1 B2
SLOVENIA
AUSTRIA
CROATIA
H
ITAL
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0 25 50 km
The most important bora property is its gustiness. We studied bora gusts by using new observa-tions collected during the four-month period in 2012. On less than 2 km distance, bora velocity more than doubles. We compared bora forecasts of the SPACE-SI prognostic model with the ob-servations to show that current forecast models lack the ability to describe the bora gustiness.
Example of the Adriatic bora forecast by SPACE-SI model valid for 10.2. 2012 at 19.00.
Bora in Vipava ValleyAnalysis of Observational and Forecast Data
SECONDARY SCHOOLDiocesan Gymnasium Vipava
Small Satellites Systems and Services - The 4S Symposium 2012Portorož, Slovenia, 4-8 June 2012
AUTHORS: Nejc Povšič, Andraž Jurinčič, Rok Žorž,Ana Čufer, Nika Obed, Mirjam Miletič, Kristijan Zorn,
Domen Rabak, Rok Miklavčič, Benjamin Smrdel, Dominik Vrčon
SUPERVISORS: Nadja Pregeljc, Vladimir Anžel,Sebastijan Mozetič, Jože Rakovec, Nedjeljka Žagar,
Rahela Žabkar, Gregor Skok, Luka Honzak, Vanja Blažica
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