Analiza zavjetrinskih oluja u Skandinavskom gorju na temelju regionalnog klimatskog modela kilometarske rezolucije

master's thesis

• Title (english): Analysis of downslope windstorms in the Scandes based on a kilometer-scale regional climate model
• Author: Patrik Jureša
• Mentor: Danijel Belušić (mentor)
• Committee member: Danijel Belušić (predsjednik povjerenstva)
• Committee member: Branko Grisogono (član povjerenstva)
• Committee member: Iva Dasović (član povjerenstva)
• Committee member: Željko Večenaj (član povjerenstva)
• Committee member: Ivica Sović (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Geophysics); Zagreb
• Defense date and country: 2022-09-23, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Geophysics; Meteorology and Climatology

Abstract

Zavjetrinska oluja mezoskalni je meteorološki fenomen koji se javlja u planinskim predjelima. Vjetar je to čije srednje satne brzine mogu premašiti 20 m·s−1, a udari i 50 – 70 m·s−1. Zavjetrinska oluja može pospješiti lokalno nagle promjene u temperaturi i drugim meteorološkim parametrima, ali i nepovoljno djelovati na okoliš i ljude.
U ovom radu razmatrani su podaci dobiveni provedbom projekta NorCP koristeći model HCLIM38-AROME koji je bio ugniježđen u mrežu modela HCLIM38-ALADIN.
Rubni uvjeti uzeti su iz ERA-Interim reanalize. Simulacije su pokrile 20 godina, 1998. – 2017., za područje Skandinavskog poluotoka, odnosno Skandinavskog gorja.
Skandinavsko gorje vrlo je izazovno za modeliranje i proučavanje njegovog utjecaja na vrijeme zbog izrazite kompleksnosti. Okruženost oceanom i morima, strme planine s mnogo ispresijecanih klanaca, fjordova i vrhova utječu na strujanje te ga mijenjaju i dinamički i termodinamički.
U ovom radu istraživana je povezanost sinoptičke situacije i zavjetrinskih oluja na četiri naknadno podijeljene poddomene. Kako bi se pravilnost mogla uočiti, uvedeno je 10 prije konstruiranih cirkulacijskih tipova. Nakon analize broja zavjetrinskih oluja po sezonama, pristupilo se detaljnijoj analizi zimske sezone (DJF) i to po svim cirkulacijskim tipovima i poddomenama. Rezultati pokazuju kako se smjerovi zavjetrinskih oluja po poddomenama i cirkulacijskim tipovima ne razlikuju značajno.
Proučavana je promjena temperature u područjima nastupa zavjetrinskih oluja, odnosno ima li vjetar burski ili fenski karakter. Budući da se pokazalo kako se cirkulacijski tipovi na poddomenama međusobno klimatološki ne razlikuju, analizirani su pojedini termini koji su uzrokovali najveći broj zavjetrinskih oluja kako bi se pokušao ustanoviti uzrok tomu. Izabrano je pet primjera: dominantno hlađenje, dominantno grijanje, dva termina gdje je jasna podjela između hlađenja i grijanja te heterogeni slučaj kojeg karakterizira nepravilni prostorni raspored grijanja i hlađenja. Razmatranje navedenih slučajeva ukazuje na kompleksnost situacije te pokazuje kako pri proučavanju lokalnih meteoroloških fenomena, kao što su zavjetrinske oluje, više faktora može imati značajnu ulogu.

Abstract (english)

Downslope windstorms are mesoscale meteorological phenomena that occur in mountainous regions. The hourly average speed of these winds can exceed 20 m·s−1, and the gusts can go up to 50 — 70 m·s−1. Downslope winds can locally enhance abrupt changes in temperature and other meteorological parameters, but can also negatively affect the environment, and people as well.
The data analyzed in this study was obtained by the NorCP project using the HCLIM38-AROME model which is nested in the HCLIM38-ALADIN model grid. Boundary conditions were obtained from the ERA-Interim reanalysis. The simulations covered 20 years, from 1998 to 2017, for the region of the Scandinavian peninsula, or more precisely, the Scandes. Due to their complexity, it is particularly challenging to model and study the effects of the Scandes on the weather. The seas and oceans surrounding the Scandinavian region, steep mountains with abundant intersecting canyons, fjords, and peaks all affect the wind flow, changing it dynamically and thermodynamically.
This study addresses the connection between the synoptic situation and downslope windstorms in four subsequently divided subdomains. Ten large-scale circulation types have been introduced to find potential regularity. After counting the number of downslope windstorms per season, a more detailed analysis of circulation types and subdomains of the winter seasons (DJF) was conducted. The results show that the downslope windstorms’ directions per subdomain and circulation types do not differ significantly.
The temperature change in the regions of downslope winds was studied, i.e., if the wind has a bora or foehn character. It was shown how the circulation types on the subdomain do not differ from each other climatologically. To understand why that is, the analysis of individual dates which caused the highest number of downslope windstorms was conducted. Five examples were selected: dominant cooling, dominant heating, two dates where the clear difference between cooling and heating can be seen, and a heterogenous case. The consideration of the mentioned cases indicates the complexity of the situation and shows how numerous factors can play a significant role when trying to understand local meteorological phenomena like downslope windstorms.

• Keywords: ALADIN; AROME; bura; cirkulacijski tip; fen; HCLIM38; klimatski model; NorCP; Skandinavija; temperatura; vjetar; zavjetrinska oluja
• Keywords (english): ALADIN; AROME; bora; circulation type; climate model; downslope windstorm; foehn; HCLIM38; NorCP; Scandes; Scandinavia; temperature; wind
• Language: croatian
• URN:NBN: urn:nbn:hr:217:158988
• 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: 2022-09-26 07:02:07