Renée M. Fredensborg Hansen

❄️Theory and practice❄️
In Sisimiut, Greenland, we teach a DTU course called Extreme Climate and Physical Nature on the Arctic Semester. Earlier this week 30+ students practiced drilling in the ice on the lake in the center of town after learning the theory last week.
#CryoTeaching #ArcticDTU

Mikkel suited up for field work in front of a snowcooter on Svalbard

Northern lights visible over the mountains seen at night from a tent in the field

Our PhD Student @mikkelaabykruse.bsky.social is currently getting a taste of what it is like to do fieldwork in the Arctic at The University Centre in Svalbard (UNIS)❄️🥽 🧤 Working on a glacier is no safe or easy task, and UNIS is a great place to learn the ropes of what it means to be a glaciologist!

Anticipating CRISTAL: an exploration of multi-frequency satellite altimeter snow depth estimates over Arctic sea ice, 2018–2023 Abstract. The EU and ESA plan to launch a dual-frequency Ku- and Ka-band polar-orbiting synthetic aperture radar (SAR) altimeter, the Copernicus Polar Ice and Snow Topography Altimeter (CRISTAL), by 2...

🚀 Excited for Copernicus @esa.int #CRISTAL! This mission’s dual‑freq Ka/Ku #altimeter aims to measure snow depth on sea ice. A new UiT‑led study (feat. @reneefredensborg.bsky.social) explores current laser/radar data + simulates CRISTAL waveforms. Check it out ➡️ tc.copernicus.org/articles/20/... ❄️🧊

One year into the ESA Digital Twin (DT) Earth Ice Sheets project ❄️@eo4cryo.bsky.social and @tabea-rettelbach.bsky.social with other @esa.int DTs at the science meeting in Frascati to present the pre-operational dtc-ice-sheets.org & new ideas for holistic data cubes 🛰️🌐 #DigitalTwinEarth #IceSheets

🍾🥂One of our most exciting pieces of news this month must be the hand-in of Anna Puggaard's PhD thesis on "Earth observation for surface mass balance" on January 15, celebrated with cake and bubbles! We look forward to seeing her in the office as a postdoc in February, after a well-deserved break! 🏝️

📢 Going to #EGU26? Do you work with #radars on icy and rocky surfaces? ➡️Look no further!

Submit an abstract to this session, convened by our @kirkscanlan.bsky.social and @reneefredensborg.bsky.social with Hameed Moqadam! The deadline is fast approaching ⌛ - submit by 15 January 2026 at 13:00 CET!

Heading to #EGU26 and use #radar to study terrestrial and planetary surfaces (both icy and rocky 🤯)? Have we got the session for you!

Consider submitting an abstract to #EGU26 CR6.3 by January 15 2026.

Read more about the session here www.egu26.eu/session/56853

Hope to see you there!

🌟Meet our Group🌟
@mikkelaabykruse.bsky.social is a PhD student in the Cryo Group. He uses satellite remote sensing to study lakes hidden beneath the Greenland Ice Sheet 🛰️🧊🌊 Some of these lakes can contain and later release enormous amounts of meltwater. #Cryosphere #RemoteSensing #Greenland

Great to be at the 2026 Greenland Ice Sheet Seminar at the Niels Bohr Institute with cryosphere colleagues.

Photo: @kirkscanlan.bsky.social presenting for DTU Space.

#GreenlandIceSheet #Cryosphere #DTUSpace

ArcticNet's Annual Scientific Meeting (ASM) 2025 Join ArcticNet's Annual Scientific Meeting (ASM) 2025, December 15-18, 2025. Learn more on Fourwaves.

To round off the year and just before Christmas, I had the amazing opportunity of spending the last week in Calgary, Alberta, meeting my colleagues at @ucalgary.bsky.social while participating in the ArcticNet's Annual Science Meeting #ASM25, and presenting my #MEOPAR funded project #SNOWMASS ❄️🛩️🛰️! ➡️

Rasmus and @tabea-rettelbach.bsky.social are in Budapest this week at HungaroMet for the PISCO & @polarres.bsky.social hackathon! 🇭🇺
With 20 other students and instructors, they’re exploring projects that combine climate model outputs with in-situ and EO data to better understand our Polar regions.🌍❄️

It may be difficult for the untrained eye to see - but we were of course dressed in the colors of glaciers at last weeks Christmas party at DTU Space🧊❄️🎄

Our office is now ready for Halloween 🎃 🎃

DTU Space was at the Danish Climate Science Symposium 2025 🇩🇰

We’re shared a handful of posters and a talk by Sebastian B. Simonsen: “From Satellites to Digital Twins – Monitoring the Greenland Ice Sheet.” Great discussions on climate, ice, and models! ❄️

#DTUSpace #Greenland #Cryosphere #DMI

We’re attending the IGS Nordic Branch Meeting 2025 in Copenhagen, at GEUS. Great to meet colleagues, hear exciting talks, and spark new discussions on ice, climate and modelling ❄️🧊📊
#Cryosphere #Glaciology #ClimateScience #IceSheet #PolarResearch #NordicScience #IGS2025

Multi-frequency altimetry snow depth estimates over heterogeneous snow-covered Antarctic summer sea ice – Part 1: C∕S-, Ku-, and Ka-band airborne observations Abstract. The recent alignment of CryoSat-2 to maximise orbital coincidence with the Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) over the Southern Ocean and Antarctica in July 2022, known as...

📢 New publication! Ahead of #ESA #CRISTAL, we explore dual-frequency #altimetry for estimating 🧊 snow depth over sea ice.

🛩️ Part 1: Airborne multi-freq altimetry → snow depth 👉 tc.copernicus.org/articles/19/...

🛰️ Part 2: Compare w/ CryoSat-2 & ICESat-2 #CRYO2ICE 👉 tc.copernicus.org/articles/19/...

Group picture!

We’re the Cryosphere Research Group at DTU Space, studying the polar regions using satellite remote sensing. We monitor and map changes in snow & ice, assess polar climate change impacts, and provide data to imporve polar climate models. Follow for polar science insights! ❄️#Cryosphere #PolarResearch

We are proud to be contributors to a chapter on Arctic land ice and its changes in the #AMAP Assessment Report 2026!❄️

#AMAP (Arctic Monitoring and Assessment Programme) is the working group under the #ArcticCouncil that produces science-based assessments to inform policy and decision-making ❄️

The Greenlandification of Antarctica - Nature Geoscience Climate and ice sheet processes in Antarctica increasingly reflect those observed earlier in Greenland. Applying process insights from Greenland can improve projections of future Antarctic ice and climate behaviour.

Antarctica is undergoing “greenlandification,” with ice loss processes mirroring Greenland ❄️🌍 New paper out in Nature Geoscience with DTU Space contributions on key signs: doi.org/10.1038/s415... #ClimateChange #Antarctica #Greenlandification

Mai is presenting PRODEM for the 2019 summer, focusing on three big outlet glaciers. More interested in PRODEM? Have a look at the paper: https://doi.org/10.5194/essd-16-5405-2024

🌍✨Great energy at DTU Space with a visit from Unge GIS Brugere!

Yesterday, we welcomed GIS users to #DTUSpace. The visit focused on spatial data from #EarthObservations and methods for tackling geospatial challenges, highlighting the importance of precise geospatial data in the Arctic and beyond 🌍❄️

Last week, @eo4cryo.bsky.social and @spacehsk.bsky.social were in Iceland and NE Greenland on an airborne #FieldCampaign sampling key data over #SeaIce and #LandIce with a brand-new instrument #CRISTALair🛩
Cutting-edge science in action, unlocking insights for future satellites🛰 #EarthObservation

Congratulations to Behzad Forouzi Feshalami for defending his PhD thesis: "Numerical modeling of wave-induced erosion of floating icebergs" - a valuable contribution to improving our understanding of ice–ocean interactions! 🌊🧊

In collaboration with #NTNU, supervised by @spacehsk.bsky.social 🎓

Presentation - Session 9: Cryosphere Altimetry Calibration/Validation I

S9-28: Operational Fiducial Reference Measurements over Sea Ice in support of Sentinel-3 validation (ESA St3TART-FO project) 🛰️🛩️❄️🧊 #St3TART-FO

Presentation - Session 9: Cryosphere Altimetry Calibration/Validation I

S9-14: Validation Methodologies for CRISTAL In-Flight Level-2 Land Ice Products – An Overview from the CRISTAL IN-PROVA Project 🛰️🛩️❄️ #IN-PROVA

Suggestions for #CRISTAL validation? Submit here ➡️ forms.office.com/e/LkSrJnPFTh

Dual-hemisphere sea ice thickness reference measurements from multiple data sources for evaluation and product inter-comparison of satellite altimetry Abstract. Sea ice altimetry currently remains the primary method for estimating sea ice thickness from space, however time-series of sea ice thickness estimates are of limited use without having been ...

Presentation - Session 10: Cryosphere Altimetry Calibration/Validation II

S10-33: Dual-hemisphere Sea Ice Reference measurements from multiple data sources tailored for evaluation and product inter-comparison of satellite altimetry 🛩️❄️🧊 #CCI

Interested? essd.copernicus.org/preprints/es...

Poster Session

SP-43: Validation Methodologies for CRISTAL In-Flight Level-2 sea ice and iceberg products within the framework of the CRISTAL IN-PROVA Project 🛰️🛩️❄️🧊

Suggestions for validation scenarios or data to support #CRISTAL and synergies with CEMs? ➡️Submit here: forms.office.com/e/KkVhdzTwth

2nd International Review Workshop on Satellite Altimetry Cal/Val & Metrology 2nd International Review Workshop on Satellite Altimetry Cal/Val & Metrology The 2nd International Review on Satellite Altimetry Calibration/Validation (Cal/Val) and Metrology is to be held in Chania,...

Last week, @reneefredensborg.bsky.social, Kristina Belinska and Stine Rose enjoyed the Mediterranean sun ☀️ in Crete while presenting results from @esa.int projects #S3MPC #St3tART-FO #IN-PROVA #CCI on calibration and validation of satellite altimetry during the calval4altcrete2025.eu ➡️

Brand new website for the Cryo Group at DTU is now live! Thanks to @reneefredensborg.bsky.social for making us look so good 🤪

www.space.dtu.dk/english/rese...

Kirk, Reneé & Tabea

These past three days, @reneefredensborg.bsky.social, @tabea-rettelbach.bsky.social ‬& @kirkscanlan.bsky.social participated in the Symposium on Technology Advancement for Ice Remote Sensing (STAIRS) in Copenhagen, organised by the University of Copenhagen and the University of Manitoba 🛰️❄️

Welcome to our new bachelor students! 🎓

Yesterday marked the start of the new study year at DTU, where we welcomed 42 new bachelor students to our Earth and Space Physics and Engineering programme. Our head of study Sine Hvidegaard made sure the students got a good intro to their new student life.