ǂThe ǂstratospheric polar vortex under future climate change scenarios

master thesis

Manca Fifnja (Author), Gregor Skok (Mentor), Khalil Karami (Co-mentor)

Abstract

The term polar vortex represents an area of cold polar air and low pressure that encircles the pole in mid or high latitudes and is bounded by strong planetary-scale westerly flow. Two distinct polar vortices can be found in the Earth’s atmosphere: a tropospheric and a stratospheric polar vortex. While the tropospheric polar vortex exists all year round, the stratospheric polar vortex only appears in the winter months. The breakdown of the stratospheric polar vortex is represented by the reversal of zonal mean zonal wind (ZMZW) and is called a Sudden stratospheric warming (SSW) event. Such events can also have an impact on weather at the surface. Just like many other atmospheric features, polar vortices are nowadays being affected by global warming. Scientists are trying to research ways of deliberate intervention in the Earth’s natural systems to help reduce the effects of global warming. This process is called geoengineering and one of the proposed techniques are stratospheric aerosols, which represent injecting small, reflective particles into the upper atmosphere. This technique was also used in Stratospheric Aerosol Geoengineering Large Ensemble Project (GLENS) simulation. In this work we analyze data from GLENS simulation to observe the influence of increased amount of greenhouse gases and geoengineering on the stratospheric polar vortex. With the analysis of zonal mean temperature (ZMT), ZMZW and potential vorticity (PV) fields we found that the stratospheric polar vortex became stronger in both hemispheres in both future climates. We also found that there was no important change in the onset date of the final SSW event in the Northern hemisphere (NH). With the analysis of major mid-winter SSW events, we found that the change in the onset date was unimportant, but the frequency of such events has also changed.

Keywords

polar vortex;sudden stratospheric warmings;geoengineering;climate change;

Data

Language:	English
Year of publishing:	2022
Typology:	2.09 - Master's Thesis
Organization:	UL FMF - Faculty of Mathematics and Physics
Publisher:	[M. Fifnja]
UDC:	551.58
COBISS:	123509763
Views:	15
Downloads:	1
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	Slovenian
Secondary title:	Polarni vrtinec v stratosferi pod vplivom različnih podnebnih scenarijev
Secondary abstract:	Izraz polarni vrtinec najpogosteje predstavlja območje hladnega polarnega zraka in nizkega tlaka, ki obdaja pol in ga omejujejo močni zahodni tokovi. V Zemljini atmosferi lahko najdemo dva različna polarna vrtinca: troposferski in stratosferski polarni vrtinec. Medtem ko troposferski polarni vrtinec obstaja skozi celotno leto, se stratosferski polarni vrtinec pojavi le v zimskih mesecih. Razpad stratosferskega polarnega vrtinca je predstavljen z obratom zonalnih vetrov in ga imenujemo dogodek nenadnega segrevanja stratosfere (SSW). Takšni dogodki lahko vplivajo tudi na vreme na površju. Tako kot na številne druge atmosferske značilnosti tudi na polarni vrtinec danes vpliva globalno segrevanje. Zato znanstveniki iščejo načine namernega poseganja v naravne sisteme Zemlje, da bi zmanjšali učinke globalnega segrevanja. Temu pravimo geoinženiring, ena od predlaganih tehnik geoinženiringa pa so stratosferski aerosoli. Ta tehnika predstavlja vbrizgavanje majhnih odbojnih delcev v zgornje plasti atmosfere in je bila uporabljena tudi v GLENS modelu. V tem delu bomo analizirali podatke iz GLENS simulacije in opazovali vpliv povečane količine toplogrednih plinov in geoinženiringa na stratosferski polarni vrtinec. Z analizo polj zonalne temperature, zonalnega vetra in potencialne vrtinčnosti (P V ) smo opazili, da je polarni vrtinec postal močnejši v obeh prihodnjih podnebjih na obeh poloblah. Opazili smo tudi, da je bila sprememba v datumu nastopa končnega SSW dogodka nebistvena. Z analizo močnih med zimskih SSW dogodkov smo prepoznali, da sprememba v datumu nastopa prav tako ni bila bistvena, opazili pa smo tudi spremembo v frekvenci takih dogodkov.
Secondary keywords:	polarni vrtinec;nenadno segrevanje stratosfere;geoinženiring;podnebne spremembe;
Type (COBISS):	Master's thesis/paper
Study programme:	0
Embargo end date (OpenAIRE):	1970-01-01
Thesis comment:	Univ. v Ljubljani, Fak. za matematiko in fiziko, Oddelek za fiziko
Pages:	108 str.
ID:	16619289