Postdoc at @DTUSpace with multi-frequency altimetry observations of sea ice 🛰️🧊❄️ Tweets are my own.
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Joined April 2012
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Just in time for #Cryo2iceSymposium next week! Have a look at our preprint on cracking the snow code from altimetry using multi-frequency airborne observations along a dual-frequency near-coincident @esa_cryosat and @NASA_ICESat2 orbit! Marking also the last study of my PhD! 🛰
Discussion open for comments on @EgUsphere: Exploring microwave penetration into snow on Antarctic summer sea ice along CryoSat-2 and ICESat-2 (CRYO2ICE) orbit from multi-frequency air- and spaceborne altimetry doi.org/10.5194/egusphere-20…
We've investigated the CryoVEx/DEFIANT Antarctic 2022/2023 campaign data for the CRYO2ICE sea ice under-flight on December 13 2022 over the Weddell Sea in our preprint: egusphere.copernicus.org/pre…. Have a look, and let's discuss!
Airborne data from the ESA CryoVEx/DEFIANT Antarctic campaign of 2022/23 is now available on CS2EO!
Time to delve in 👇
‼️earth.esa.int/eogateway/news…
ALT View from the cockpit over Fuchs Piedmont, Antarctica. Through the windsgreen, ice and snow covers the ground under a clear blue sky, the white tips of mountains rising high over an ice sheet that stretches as far as the eye can see. (credits: ESA–I. Lawrence) https://blogs.esa.int/campaignearth/2023/02/23/diary-of-a-polar-scientist-two-weeks-leading-an-airborne-campaign-in-antarctica/
Renée Mie Fredensborg Hansen retweeted
Discussion open for comments: Dual-hemisphere sea ice thickness reference measurements from multiple data sources for evaluation and product inter-comparison of satellite altimetry doi.org/10.5194/essd-2024-23…
Renée Mie Fredensborg Hansen retweeted
It was great to see @rmfredensborg present this at #Cryo2ice!
New preprint: "Exploring microwave penetration into snow on Antarctic summer sea ice along #CryoSat and ICESat-2 (CRYO2ICE) orbit from multi-frequency air- and spaceborne altimetry"
👉egusphere.copernicus.org/pre…
ALT Snow. Image by Anja from Pixabay
Excited for #CRISTAL? So are we! Take a look at our preprint investigating the potential for snow depth estimation from dual-frequency altimetry using current satellite missions, and get a taste of future expectations with simulations based on the design of #IRIS!
Take a look at our new preprint in @EGU_TC Anticipating CRISTAL: An exploration of multi-frequency satellite altimeter snow depth estimates over Arctic sea ice, 2018–2023 egusphere.copernicus.org/pre… @CIRFA_SFI @UiTNorgesarktis @Bristol_Glac @CPOM_news @DTUcryo @esa_cryosat @NASA_ICE
Renée Mie Fredensborg Hansen retweeted
Take a look at our new preprint in @EGU_TC Anticipating CRISTAL: An exploration of multi-frequency satellite altimeter snow depth estimates over Arctic sea ice, 2018–2023 egusphere.copernicus.org/pre… @CIRFA_SFI @UiTNorgesarktis @Bristol_Glac @CPOM_news @DTUcryo @esa_cryosat @NASA_ICE
Suggestions going forwards? 1⃣ This is only one example of airborne data, we need to evaluate more to understand impact of different systems and sesonal signals! 2⃣ Modelling backscatter taking into account the differences between air- and spaceborne systems can provide insights!
Comparison to the underflown CRYO2ICE orbit? Difficult! Scattering mechanisms, impact of range resolution and different spatial coverage seem to play a signicant role! We need to smooth significantly (up to 25 km) and even then, correlations are only moderate!
❗️ Ku-band could potentially be used, independently, to derive snow depth if applying multi-peak re-trackers, and when distinguishable interfaces are from the snow-ice interfaces. However, in most cases, Ku-band didn't penetrate as far as the C/S-band (snow-radar) could!
What are some main conclusions then? ❗️ Air-snow interface scattering contributes significantly and can be distinguished! Assumptions of one singular scattering interface at airborne scales is insufficient, and previously standard methods used do not capture expected interfaces!
So did we crack the code? Hardly - snow is incredibly complex. However, we did present a first exploration of multi-frequency altimetry at all the frequencies relevant for microwave penetration including radars at Ku-, Ka- and C/S-band, and with comparison to a scanning lidar!
Renée Mie Fredensborg Hansen retweeted
We join the 27th IAHR Int. Symp. on Ice in Gdánsk, Poland, this week. @rmfredensborg presented sea ice ridge statistics in Barents Sea and Fram Strait from #ICESat-2! 🛰️
Interesting discussions on deformed ice, offshore ice-ocean-structure, applications of remote sensing! ⛴️🧊❄️
Renée Mie Fredensborg Hansen retweeted
@hskourup and @rmfredensborg at ESA-ESRIN for the #St3TART-FO kick-off meeting! Exited to continue on the procedures for establishing fiducial reference measurements (#FRMs) for #Sentinel-3 Altimetry Cryo products 🛰, to support validation of altimetry sea ice variables ❄️🧊
Renée Mie Fredensborg Hansen retweeted
This is just the sort of thing we're looking for at the #Cryo2ice symposium 🤩
"Arctic Freeboard and Snow Depth From Near‐Coincident CryoSat‐2 and ICESat‐2 (CRYO2ICE) Observations: A First Examination of Winter Sea Ice During 2020–2022"
👉agupubs.onlinelibrary.wiley.…
❗️❗️❗️Are you as excited about the upcoming #ESA #CRISTAL mission and estimating snow depth from dual-frequency altimetry along the orbits as us? We've evaluated this possiblity - albeit from laser and radar - from Arctic #CRYO2ICE orbits for 2020-2022! ➡️agupubs.onlinelibrary.wiley.…
Renée Mie Fredensborg Hansen retweeted
Paper celebration day! 📝 We may not be able to share the snacks with you, but we can definitely share our latest papers! Check out the links below if you're looking for some Sunday reading material.
Enjoy diving into the research! 📚
Renée Mie Fredensborg Hansen retweeted
As a teaser here is the dream team earlier this week on the ice collected amazing in-situ, drone and airborne data. Photo credit: Thomas Newman (@ES_UCL).
