The PhD defence and trial lecture are fully digital and streamed using Zoom. The host of the session will moderate the technicalities while the chair of the defence will moderate the disputation. A limited number of seats are available in auditorium 1.
Trial lecture
Evolution of extreme weather in Northern Europe in the context of climate change under different scenarios
Conferral summary (in Norwegian)
Når underkjølte vanndråper i atmosfæren når et fast objekt kan det fryse fast på objektet og danne store mengder is. Dette kalles atmosfærisk ising, og kan forårsake skader på infrastruktur slik som kollaps av kraftlinjer og at fly mister kontrollen. Avhandlingen viser hvordan varsling av atmosfærisk ising kan forbedres gjennom å bedre gjengi skyprosessene som fører til underkjølt vann i værvarslingsmodellen som i dag benyttes ved Meteorologisk institutt.
Main research findings
Popular scientific article about Engdahls`s dissertation:
Improved predictions of atmospheric icing
Atmospheric icing happens when supercooled liquid droplets inside the clouds come into contact with a solid object and freeze. The accumulated ice can bring down infrastructure such as transmission lines and cause aircraft to lose control. Accurate knowledge of the amount of supercooled liquid is crucial to forecast atmospheric icing, yet remain challenging due to the myriads of complex physical processes going on inside the clouds.
This doctoral thesis in cloud physics aims to improve the representation of supercooled liquid water in the weather forecast model HARMONIE-AROME, used for operational forecasts by MET-Norway and many other European countries.
Through idealised experiments the parts of the model’s microphysics scheme, responsible for the forecast of clouds are modified. The final modified model is then validated over a 3-month winter season to test its ability to forecast supercooled liquid water and thereby atmospheric icing. The results show that the modified scheme has a better representation of supercooled liquid and gives better estimates of ice loads on transmission lines and forecasts of aircraft icing.
Photo and other information:
Press photo: Bjørg Jenny Kokkvoll Engdahl, portrait; 500px. Photo: Privat
Other photo material: Photo with description and credit as specified in the article above, size 1000px.
