{"id":6122,"date":"2026-10-19T09:48:30","date_gmt":"2026-10-19T09:48:30","guid":{"rendered":"https:\/\/phd.hi.is\/doktorsvorn\/doktorsvorn-i-jardedlisfraedi-louise-steffensen-schmidt\/"},"modified":"2026-10-19T09:48:30","modified_gmt":"2026-10-19T09:48:30","slug":"doktorsvorn-i-jardedlisfraedi-louise-steffensen-schmidt","status":"publish","type":"phd_defence","link":"https:\/\/phd.hi.is\/en\/doktorsvorn\/doktorsvorn-i-jardedlisfraedi-louise-steffensen-schmidt\/","title":{"rendered":"Doktorsv\u00f6rn \u00ed jar\u00f0e\u00f0lisfr\u00e6\u00f0i – Louise Steffensen Schmidt"},"content":{"rendered":"
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Doktorsefni:<\/strong>\u00a0Louise Steffensen Schmidt<\/p>\n

Heiti ritger\u00f0ar:<\/strong>\u00a0Skammt\u00edma og langt\u00edma \u00fer\u00f3un Vatnaj\u00f6kuls hermd me\u00f0 reiknil\u00edk\u00f6num<\/p>\n

Andm\u00e6lendur:<\/strong><\/p>\n

Dr. Shawn Marshall, pr\u00f3fessor vi\u00f0 H\u00e1sk\u00f3lann \u00ed Calgary, Kanada<\/p>\n

Dr.\u00a0<\/strong>Xavier Fettweis, s\u00e9rfr\u00e6\u00f0ingur vi\u00f0 H\u00e1sk\u00f3lann \u00ed Liege, Belg\u00edu<\/p>\n

Lei\u00f0beinandi:<\/strong>\u00a0Dr. Gu\u00f0finna A\u00f0algeirsd\u00f3ttir, pr\u00f3fessor vi\u00f0 Jar\u00f0v\u00edsindadeild H\u00e1sk\u00f3la \u00cdslands
<\/strong><\/p>\n

Einnig \u00ed doktorsnefnd: <\/strong><\/p>\n

Finnur P\u00e1lsson, verkfr\u00e6\u00f0ingur hj\u00e1 Jar\u00f0v\u00edsindastofnun H\u00e1sk\u00f3lans\u00a0<\/p>\n

Sverrir Gu\u00f0mundsson, fagstj\u00f3ri hj\u00e1 Veitum<\/p>\n

Dr. Peter L. Langen, loftslagsfr\u00e6\u00f0ingur hj\u00e1 d\u00f6nsku ve\u00f0urstofunni.<\/p>\n

Dr. Helgi Bj\u00f6rnsson, emeritus \u00e1 Jar\u00f0v\u00edsindastofnun H\u00e1sk\u00f3lans<\/strong><\/p>\n<\/p>\n

Doktorsv\u00f6rn st\u00fdrir:<\/strong>\u00a0Dr. Andri Stef\u00e1nsson, pr\u00f3fessor og varadeildarforseti Jar\u00f0v\u00edsindadeildar H\u00e1sk\u00f3la \u00cdslands<\/p>\n

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

\u00cd ritger\u00f0inni er l\u00fdst ni\u00f0urst\u00f6\u00f0um ranns\u00f3kna \u00e1 a\u00f0 nota sv\u00e6\u00f0isbundin loftlagsl\u00edk\u00f6n til a\u00f0 herma \u00fer\u00f3un Vatnaj\u00f6kuls, st\u00e6rsta j\u00f6kuls \u00cdslands, nokkra undangengna \u00e1rtugi og n\u00e6stu framt\u00ed\u00f0. Einnig er rannsaka\u00f0 hve n\u00e6m leysing j\u00f6kulsins er fyrir breytilegu endurkasti s\u00f3larlj\u00f3ss fr\u00e1 yfirbor\u00f0i (endurkastsstu\u00f0li;\u00a0 en: albedo) og \u00feykktar snj\u00f3lags a\u00f0 vori.<\/p>\n

Fyrst var meti\u00f0 hve vel sv\u00e6\u00f0isbundna loftlagsl\u00edkani\u00f0 HIRHAM5 l\u00fdsir a\u00f0st\u00e6\u00f0um \u00e1\u00a0 Vatnaj\u00f6kli me\u00f0 \u00fev\u00ed a\u00f0 bera l\u00fdsingu \u00feess vi\u00f0 m\u00e6lig\u00f6gn fr\u00e1 sj\u00e1lfvirkum ve\u00f0urst\u00f6\u00f0vum og afkomum\u00e6lingar. Endurkastsstu\u00f0ull \u00edsyfirbor\u00f0s j\u00f6kulsins (eftir a\u00f0 vetrarsnj\u00f3 hefur leyst) \u00ed l\u00edkaninu er metinn eftir g\u00f6gnum fr\u00e1 MODIS gervihnettinum. Jafnvel \u00fe\u00f3tt ni\u00f0urst\u00f6\u00f0ur l\u00edkansins ver\u00f0i \u00e1 \u00feennan h\u00e1tt n\u00e6r sanni, er enn\u00fe\u00e1 a\u00f0 jafna\u00f0i of h\u00e1r endurkastsstu\u00f0ull \u00e1 leysingat\u00edma b\u00e6\u00f0i vegna \u00feess a\u00f0 snj\u00f3\u00feykktin \u00e1 spor\u00f0um er ofmetin \u00ed l\u00edkaninu og ekki er teki\u00f0 tillit til loftborins ryks sem berst \u00ed yfirbor\u00f0i\u00f0 og dekkir \u00fea\u00f0. Vegna \u00feessa er hermda leysingin heldur minni en s\u00fa m\u00e6lda a\u00f0 jafna\u00f0i.\u00a0 \u00der\u00e1tt fyrir \u00feessa annmarka hermir l\u00edkani\u00f0 heildarafkomu j\u00f6kulsins vel og s\u00fdnir samskonar sveiflur \u00ed massa tapi og hafa veri\u00f0 m\u00e6ldar s\u00ed\u00f0an j\u00f6kul\u00e1ri\u00f0 1991-92.<\/p>\n

Ofmat \u00e1komu \u00ed HIRHAM5 er a.m.k. a\u00f0 hluta til vegna n\u00e1lgunar sem ger\u00f0 er \u00ed lofthj\u00fapshluta l\u00edkansins (hydrostatic approximation) og \u00fev\u00ed voru ger\u00f0ar tilraunir me\u00f0 a\u00f0 keyra snj\u00f3s\u00f6fnunarhluta l\u00edkansins, sem er vel sta\u00f0festur, me\u00f0 ve\u00f0urfars\u00fe\u00e1ttum fr\u00e1 \u00f6\u00f0rum loftlagsl\u00edk\u00f6num.\u00a0 Me\u00f0 \u00fev\u00ed a\u00f0 nota ve\u00f0ur\u00fe\u00e6tti fr\u00e1 ve\u00f0ursp\u00e1 l\u00edkaninu HARMONIE-AROME, sem ekki gerir \u00feessa n\u00e1lgun (non-hydrostatic model) f\u00e1st betri ni\u00f0urst\u00f6\u00f0ur fyrir afkomu Vatnaj\u00f6kuls, s\u00e9rstaklega vegna b\u00e6ttrar \u00farkomu \u00ed l\u00edkaninu.\u00a0 HARMONIE-AROME var \u00feess vegna nota\u00f0 til a\u00f0 herma leysingu Vatnaj\u00f6kuls j\u00f6kul\u00e1rin 1980 til 2015 og meta hversu n\u00e6m leysingin er fyrir \u00feykkt snj\u00f3lags a\u00f0 vori.\u00a0 Ni\u00f0urst\u00f6\u00f0ur s\u00fdna a\u00f0 leysing alls j\u00f6kulsins r\u00e6\u00f0st a\u00f0 mestu leiti af sumarve\u00f0ri, \u00fe\u00f3tt a\u00f0 leysing nor\u00f0urj\u00f6klanna; Br\u00faarj\u00f6kuls og Dyngjuj\u00f6kuls, s\u00e9 einnig mj\u00f6g h\u00e1\u00f0 \u00feykkt snj\u00f3lags a\u00f0 vori.\u00a0 \u00c1hrif endurkastsstu\u00f0uls \u00edssins \u00e1 leysingu eru einnig metin \u00e1 sama t\u00edmabili; 14% leysingar alls Vatnaj\u00f6kul er vegna br\u00e1\u00f0nunar \u00edss sem kemur undan snj\u00f3lagi vetrar en 27% leysingar Br\u00faarj\u00f6kuls.<\/p>\n

\u00der\u00f3un Vatnaj\u00f6kuls \u00ed framt\u00ed\u00f0inni er hermd me\u00f0 \u00edsfl\u00e6\u00f0il\u00edkaninu PISM og mati afkomu \u00fat fr\u00e1 loftlagsl\u00edkani sem byggir \u00e1 sp\u00e1 um \u00fer\u00f3un loftlags.\u00a0 Afkoman er hermd me\u00f0 snj\u00f3hluta HIRHAM5 l\u00edkansins me\u00f0 mismunandi ve\u00f0ur\u00fe\u00e1ttum.\u00a0 Fyrir t\u00edmabili\u00f0 1980-2016 eru nota\u00f0ir ve\u00f0ur\u00fe\u00e6ttir fr\u00e1 endurgreiningu HARMONIE-AROME l\u00edkansins.\u00a0 Fyrir t\u00edmabili\u00f0 2017-2100 eru notu\u00f0 metin fr\u00e1vik fr\u00e1 vi\u00f0mi\u00f0unart\u00edmabili (1990-2010), reiknu\u00f0 me\u00f0 HIRHAM5 me\u00f0 inngangst\u00e6r\u00f0um fr\u00e1 EC-EARTH \u00e1 j\u00f6\u00f0runum og svi\u00f0smyndunum RCP4.5 and RCP8.5 um \u00fer\u00f3un loftlags.\u00a0 Fyrir t\u00edmabili\u00f0 2100-2300 er \u00edsfl\u00e6\u00f0il\u00edkani\u00f0 keyrt \u00e1fram me\u00f0 endurteknu afkomumati \u00e1ranna 2081-2100. Vi\u00f0 lok reikninganna, hermt \u00e1r 2300, hefur Vatnaj\u00f6kull misst 45% af r\u00famm\u00e1li s\u00ednu og 25% af flatarm\u00e1li s\u00ednu, ef mi\u00f0a\u00f0 er vi\u00f0 svi\u00f0smynd RCP4.5, en misst 85% af r\u00famm\u00e1li og 65% af flatarm\u00e1li \u00fatfr\u00e1 svi\u00f0smynd RCP8.5.\u00a0 Sams konar keyrslur me\u00f0 tilt\u00e6kum framt\u00ed\u00f0arsp\u00e1m fyrir akomu \u00far CORDEX verkefninu s\u00fdna a\u00f0\u00a0 r\u00fdrnun \u00edsr\u00famm\u00e1ls getur or\u00f0i\u00f0 \u00e1 bilinu 50-95% og minnkun flatarm\u00e1ls j\u00f6kla 25-80%.<\/p>\n

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

Louise Steffensen Schmidt f\u00e6ddist 1988 og \u00f3lst upp \u00ed n\u00e1grenni Kaupmannahafnar. H\u00fan lauk B.Sc. og M.Sc. pr\u00f3fum \u00ed e\u00f0lisfr\u00e6\u00f0i fr\u00e1 Niels Bohr stofnuninni vi\u00f0 Kaupmannahafnarh\u00e1sk\u00f3la, \u00fear sem h\u00fan stunda\u00f0i n\u00e1m fr\u00e1 2009-2014. \u00c1ri\u00f0 2015 h\u00f3f h\u00fan doktorsn\u00e1m vi\u00f0 H\u00e1sk\u00f3la \u00cdslands.<\/p>\n

Vi\u00f0bur\u00f0ur \u00e1 facebook<\/a><\/p>\n


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

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