Prognoziranje udara bure na temelju izlaznih polja modela ALADIN na Zračnoj luci Dubrovnik

master's thesis

• Title (english): Bora gusts forecasting using ALADIN model outputs at the Dubrovnik airport
• Author: Niko Simić
• Mentor: Željko Večenaj (mentor)
• Committee member: Željko Večenaj (predsjednik povjerenstva)
• Committee member: Branko Grisogono (član povjerenstva)
• Committee member: Ivica Sović (član povjerenstva)
• Committee member: Maja Telišman Prtenjak (član povjerenstva)
• Committee member: Josip Stipčević (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Geophysics); Zagreb
• Defense date and country: 2019-02-27, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Geophysics; Meteorology and Climatology

Abstract

Cilj ovog rada bio je pokušati pronaći prikladan parametar za prognozu udara bure na Zračnoj luci Dubrovnik (ZLD) iz ALADIN modela rezolucija 4 km i 8 km. U tu svrhu korišteni su podatci epizoda bura u razdoblju od 15. prosinca 2017. do 31. ožujka 2018. izmjereni pomoću dva anemometra na ZLD.
Iz izmjerenih podataka je izračunata kinetička energija turbulencije (TKE) i viskozna disipacija ɛ. Potvrđena je linearno rastuća veza izmjerenih udara i √TKE kao i ɛ ~ TKE3/2. Iz spomenutog slijedi da je ɛ1/3 proporcionalan brzini udara što je i povrđeno.
Uspoređeni su TKE ALADIN-a s izmjerenim TKE-om, kao i horizontalna komponenta brzine vjetra ALADIN-a s brzinom udara i izmjerenim TKE. Usporedbe su napravljene u vremenskoj domeni i pomodu dijagrama raspršenja. U vremenskoj domeni pokazalo se da modelirane veličine ne procjenjuju dobro varijacije izmjerenih veličina. Dodatno, TKE ALADIN-a redovito potcjenjuje izmjereni TKE. U dijagramima raspršenja, pokušano je statistički pristupiti prognozi izmjerenih veličina pomodu modeliranih. Pokazalo se da su problemi takvom pristupu velika varijanca medijana dijagrama raspršenja i na nekim područjima povedan interkvartilni raspon.
Uočena je sličnost oblika krivulja dijagrama raspršenja izmjerenih veličina i veličina iz modela vezanih uz N tip i SM tip bure (N tip je otvoreni tip bure koji se proteže kroz cijelu troposferu, a SM tip se odnosi na standardni model). Postavilo se pitanje jesu li spomenuti oblici posljedica varijance uzorkovanja ili su posljedica toga da N tip i SM tip bure imaju svoju fenomenologiju. U tu svrhu, proveden je test usporedbom krivulja dijagrama raspršenja oba tipa bure s nasumično odabranim skupovima bura. Za N tip je potvrdeno da oblik krivulje nije posljedica varijance uzorkovanja, dok za SM tip zbog premalog uzorka ne-SM tipa bure nije se moglo ništa zaključiti.

Abstract (english)

The goal of this paper is to try and find the most adequate ALADIN model parameter for forecasting bora gusts at Dubrovnik Airport. Data used came from two anemometers placed at Dubrovnik Airport during the period of December 15th 2017 - March 31st 2018.
Turbulence kinetic energy (TKE) was calculated as well as its viscous dissipation rate ε. Several links were confirmed: linear relationship between bora gust speed and √TKE and ɛ1/3 as well as ɛ1/3 proportionality with bora gust speed.
In time domain and using scatter plots, we compared various variables: TKE parametrised from ALADIN with TKE derived from measurements, ALADIN horizontal wind component with gust speed and measurement-derived TKE.
Modeled variables do not successfully estimate those derived from measurements in time domain. Additionally, ALADIN TKE typically underestimates measured TKE. A statistical approach was used concerning scatter plots. Forecasting using statistical approach was found to be defective due to large median variance and, for certain values, increased interquartile range. We also observed similar shapes of the curves regarding N and SM types of bora wind in scatter plots (N type bora extends through the entire troposhere, and the SM type refers to standard model bora). A question arised whether the aforementioned shapes were the result of sampling variance or the phenomenology of bora types. Curves associated with N and SM boras were compared with randomly selected bora episodes. For the N type, it has been successfully verified that the shape of the curve is not a consequence of sampling variation, while for the SM type no conclusion was found owing to too small non-SM type sample size.

• Keywords: Bura; Zračna luka Dubrovnik; ALADIN; TKE
• Keywords (english): Bora; Dubrovnik Airport; ALADIN; TKE
• Language: croatian
• URN:NBN: urn:nbn:hr:217:406163
• Study programme: Title: Graduate university study pf Physics - Geophysics; specializations in: Seismology and Physics of the Earth's Interior, Meteorology and Physical Oceanography; Course: Meteorology and Physical Oceanography; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra fizike – geofizike (magistar/magistra fizike – geofizike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-03-06 13:36:35