{"id":6298,"date":"2026-10-19T09:48:44","date_gmt":"2026-10-19T09:48:44","guid":{"rendered":"https:\/\/phd.hi.is\/doktorsvorn\/doktorsvorn-i-byggingarverkfraedi-andri-gunnarsson\/"},"modified":"2026-10-19T09:48:44","modified_gmt":"2026-10-19T09:48:44","slug":"doktorsvorn-i-byggingarverkfraedi-andri-gunnarsson","status":"publish","type":"phd_defence","link":"https:\/\/phd.hi.is\/en\/doktorsvorn\/doktorsvorn-i-byggingarverkfraedi-andri-gunnarsson\/","title":{"rendered":"Doktorsv\u00f6rn \u00ed byggingarverkfr\u00e6\u00f0i – Andri Gunnarsson"},"content":{"rendered":"
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Doktorsefni:<\/strong> Andri Gunnarsson<\/p>\n

Heiti ritger\u00f0ar:<\/strong> L\u00edkanger\u00f0 orku- og massajafna\u00f0ar fyrir \u00e1rst\u00ed\u00f0arbundinn snj\u00f3 og j\u00f6kla me\u00f0 hagn\u00fdtingu fjark\u00f6nnunar \u00e1 \u00cdslandi. (Modeling of energy and mass balance using remote sensing for seasonal snow and glaciers in Iceland)<\/p>\n

Andm\u00e6lendur:<\/strong>
Dr. Jason E. Box, ranns\u00f3knapr\u00f3fessor vi\u00f0 J\u00f6klafr\u00e6\u00f0i- og loftslagsdeild, GEUS, Danm\u00f6rku
Dr. Peter L. Langen, pr\u00f3fessor vi\u00f0 Umhverfisv\u00edsindadeild H\u00e1sk\u00f3lans \u00ed \u00c1r\u00f3sum, Danm\u00f6rku<\/p>\n

Lei\u00f0beinandi:<\/strong>\u00a0 Dr. Sigur\u00f0ur M. Gar\u00f0arsson, pr\u00f3fessor vi\u00f0 Umhverfis- og byggingarverkfr\u00e6\u00f0ideild H\u00cd og forseti Verkfr\u00e6\u00f0i- og n\u00e1tt\u00faruv\u00edsindasvi\u00f0s<\/p>\n

Einnig \u00ed doktorsnefnd:
<\/strong>Dr. Jessica D. Lundquist, pr\u00f3fessor vi\u00f0 University of Washington, Bandar\u00edkjunum
Dr. \u00d3li G. B. Sveinsson, forst\u00f6\u00f0uma\u00f0ur Vatnsaflssvi\u00f0s Landsvirkjunar
Dr. T\u00f3mas J\u00f3hannesson, fagstj\u00f3ri \u00e1 svi\u00f0i j\u00f6klafr\u00e6\u00f0i hj\u00e1 Ve\u00f0urstofu \u00cdslands<\/p>\n

Doktorsv\u00f6rn st\u00fdrir:<\/strong> Dr. Bjarni Bessason, pr\u00f3fessor vi\u00f0 Umhverfis- og byggingarverkfr\u00e6\u00f0ideild H\u00cd<\/p>\n

\u00c1grip<\/strong><\/p>\n

Fj\u00f6ldi gervitungla \u00e1 sporbraut um j\u00f6r\u00f0u gera athuganir \u00e1 yfirbor\u00f0i jar\u00f0ar sem geta b\u00e6tt mat og auki\u00f0 skilning \u00e1 e\u00f0lisfr\u00e6\u00f0ilegum ferlum \u00ed vatna- og j\u00f6klafr\u00e6\u00f0i. M\u00f6rg \u00feessara ferla er krefjandi a\u00f0 skilja og herma r\u00e9tt me\u00f0 reiknil\u00edk\u00f6num, eins og snj\u00f3hulu og endurkastsstu\u00f0ul yfirbor\u00f0s sem huli\u00f0 er snj\u00f3 og \u00eds, en \u00fear geta fjark\u00f6nnunarg\u00f6gn b\u00e6tt skilning og auki\u00f0 g\u00e6\u00f0i hermana.<\/p>\n

\u00cd verkefninu voru fjark\u00f6nnunarg\u00f6gn notu\u00f0 til a\u00f0 b\u00faa til samfelldar t\u00edmara\u00f0ir \u00ed t\u00edma og r\u00fami fyrir daglegt mat \u00e1 snj\u00f3hulu og endurkastsstu\u00f0li fyrir yfirbor\u00f0 huli\u00f0 snj\u00f3 og \u00eds fyrir t\u00edmabili\u00f0 2000 til 2022 \u00e1 \u00cdslandi. Afur\u00f0irnar n\u00fdttu g\u00f6gn \u00far MODIS skynjara tveggja gervihnatta sem daglega f\u00f3ru yfir \u00cdsland fr\u00e1 2000. \u00der\u00f3u\u00f0 var \u00farvinnslua\u00f0fer\u00f0 sem n\u00fdtti g\u00f6gn skynjaranna og t\u00f3k tillit til mikillar sk\u00fdjahulu \u00e1 \u00cdslandi. T\u00f6lfr\u00e6\u00f0ilegar a\u00f0fer\u00f0ir voru \u00fer\u00f3a\u00f0ar til a\u00f0 s\u00eda villur \u00ed g\u00f6gnunum og a\u00f0fer\u00f0ir v\u00e9lr\u00e6ns n\u00e1ms n\u00fdttar til a\u00f0 flokka \u00f3flokka\u00f0a myndreiti. Afur\u00f0 \u00feessarar \u00farvinnslua\u00f0fer\u00f0ar voru samfelld g\u00f6gn \u00ed t\u00edma og r\u00fami sem bj\u00f3\u00f0a upp \u00e1 frekari greiningar, v\u00f6ktun \u00e1 breytingum og sem inntak \u00ed frekari l\u00edkanger\u00f0 af snj\u00f3 og j\u00f6klum \u00e1 \u00cdslandi. G\u00e6\u00f0i afur\u00f0anna voru sannreyndar me\u00f0 m\u00f6nnu\u00f0um athugunum, athugunum \u00far ve\u00f0urst\u00f6\u00f0um utan og \u00e1 j\u00f6klum en einnig fjark\u00f6nnunarg\u00f6gn \u00far \u00f6\u00f0rum gervihn\u00f6ttum \u00ed h\u00e6rri upplausn. Til a\u00f0 skilja betur breytileika innan \u00e1rs, sem og milli \u00e1ra, var \u00fer\u00f3a\u00f0 orkuskiptal\u00edkan sem n\u00fdtir mat \u00e1 snj\u00f3hulu og endurkastsstu\u00f0li til a\u00f0 meta betur orkuskipti yfirbor\u00f0s huli\u00f0 snj\u00f3 og \u00eds. Endurkastsstu\u00f0ull var n\u00fdttur sem inntak til a\u00f0 skor\u00f0a magn stuttbylgjugeislunar sem n\u00fdtist til leysingar og hlutfallstala snj\u00f3hulu innan myndreits utan j\u00f6kla gefur skor\u00f0ur \u00e1 magni leysingarorku tilt\u00e6kri fyrir \u00e1rst\u00ed\u00f0arbundinn snj\u00f3.<\/p>\n

Ni\u00f0urst\u00f6\u00f0urnar voru settar \u00ed samhengi vi\u00f0 st\u00f3rskalabreytileika \u00ed loftslagi og ve\u00f0ri \u00e1 og vi\u00f0 \u00cdsland, til a\u00f0 skilja betur drifkrafta breytileika fyrir \u00e1rst\u00ed\u00f0arbundinn snj\u00f3 og j\u00f6kla. Ni\u00f0urst\u00f6\u00f0urnar sta\u00f0festa mikinn breytileika innan \u00e1rs og milli \u00e1ra fyrir snj\u00f3hulu, endurkastsstu\u00f0ul og orkuskipti yfirbor\u00f0s \u00e1 \u00cdslandi. Mikill breytileiki \u00ed orkuskiptum yfirbor\u00f0s endurspeglast s\u00e9rstaklega \u00ed breytileika endurkastsstu\u00f0uls en lj\u00f3sgleypnar agnir (ryk og aska) \u00ed yfirbor\u00f0i h\u00f6f\u00f0u mikil \u00e1hrif. \u00c1hrif lj\u00f3sgleypinna agna, me\u00f0 uppruna \u00ed eldgosum e\u00f0a fr\u00e1 \u00f3st\u00f6\u00f0ugum yfirbor\u00f0um utan j\u00f6kla (sandfok), voru metin til a\u00f0 skilja betur umfang og \u00e1hrif \u00feeirra \u00e1 orkuskipti. Ni\u00f0urst\u00f6\u00f0urnar s\u00fdna umfangsmikil \u00e1hrif fyrir \u00e1r \u00fear sem miki\u00f0 magn agna sest \u00ed yfirbor\u00f0, s\u00e9rstaklega j\u00f6kla, t.d. \u00feegar eldgos eiga s\u00e9r sta\u00f0 a\u00f0 vori og sumri til. Einnig komu \u00ed lj\u00f3s tengsl sj\u00e1varhita \u00ed kringum og vi\u00f0 \u00cdslandsstrendur vi\u00f0 sk\u00fdjahulu \u00e1 landi. Sj\u00e1varhitafr\u00e1vik sunnan Gr\u00e6nlands og \u00cdslands hafa sterk vensl vi\u00f0 sk\u00fdjahulu \u00e1 \u00cdslandi yfir vor og sumar. Sk\u00fdjahula m\u00f3tar magn innfallandi stuttbylgjugeislunar fr\u00e1 andr\u00famslofti sem er tekin upp af yfirbor\u00f0i til leysingar \u00e1 snj\u00f3 og \u00eds, \u00fe.e. orkuskipti yfirbor\u00f0s. \u00d6nnur st\u00f3rskala ferli eins og Greenland Base Index (GBI) og North Atlantic Oscillation (NAO) s\u00fdndu einnig markt\u00e6k vensl vi\u00f0 lykilbreytur \u00ed orkuskiptum yfirbor\u00f0s.<\/p>\n

Um doktorsefni\u00f0<\/strong><\/p>\n

Andri Gunnarsson er f\u00e6ddur 1983. Hann lauk st\u00fadentspr\u00f3fi fr\u00e1 Menntask\u00f3lanum \u00e1 Akureyri 2004, B.Sc.-pr\u00f3fi \u00ed h\u00e1t\u00e6kniverkfr\u00e6\u00f0i fr\u00e1 H\u00e1sk\u00f3lanum \u00ed Reykjav\u00edk \u00e1ri\u00f0 2009 og meistarapr\u00f3fi \u00ed umhverfis- og byggingarverkfr\u00e6\u00f0i vi\u00f0 H\u00e1sk\u00f3la \u00cdslands \u00e1ri\u00f0 2012. Fr\u00e1 2012 hefur Andri veri\u00f0 verkefnisstj\u00f3ri hj\u00e1 Landsvirkjun og st\u00fdrt verkefnum sem sn\u00faa a\u00f0 vatnafr\u00e6\u00f0i og au\u00f0lindamati, me\u00f0 s\u00e9rstaka \u00e1herslu \u00e1 j\u00f6klaranns\u00f3knir Landsvirkjunar. Andri hefur lagt stund \u00e1 doktorsn\u00e1m samhli\u00f0a vinnu hj\u00e1 Landsvirkjun fr\u00e1 \u00e1rinu 2017, veturinn 2017-18 t\u00f3k hann hluta n\u00e1msins vi\u00f0 University of Washington \u00ed Seattle \u00ed Bandar\u00edkjunum, styrktur af Valle-sj\u00f3\u00f0num.<\/p>\n<\/div><\/div>","protected":false},"featured_media":5255,"template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"_phd_date_start":"2022-09-12T14:00:00+00:00","_phd_date_end":"2022-09-12T17:00:00+00:00","_phd_location":"A\u00f0albygging H\u00e1t\u00ed\u00f0arsalur","_phd_admission":"A\u00f0gangur \u00f3keypis","_phd_thesis_title":"L\u00edkanger\u00f0 orku- og massajafna\u00f0ar fyrir \u00e1rst\u00ed\u00f0arbundinn snj\u00f3 og j\u00f6kla me\u00f0 hagn\u00fdtingu fjark\u00f6nnunar \u00e1 \u00cdslandi. 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