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Kristoffer Aalstad Profile
Kristoffer Aalstad

@krisaalstad

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Researcher @unioslo_mn. Working on snow, permafrost, meteorology, data assimilation, and remote sensing.

Norwayish
Joined March 2018
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@EGU_BioGeo
Biogeosciences
10 months
Discussion open for comments on @EgUsphere: Inferring methane emissions from African livestock by fusing drone, tower, and satellite data
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@70sBachchan
Albert Pinto
1 year
โ€œThe market will solve climateโ€ The market:
@DailyLoud
Daily Loud
1 year
BREAKING: Oreo and Coca-Cola are teaming up to launch an Oreo-flavored Coke Zero and a Coke-flavored Oreo.
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@sgascoin
Simon Gascoin
1 year
Was 2024 a good or bad snow year? Thread!
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@krisaalstad
Kristoffer Aalstad
1 year
New preprint in @EgUsphere led by trailblazing PhD candidate Marco Mazzolini on joint ICESat-2 #spacelaser snow depth and Sentinel-2 snow cover data assimilation with MuSA in the SNOWDEPTH @forskningsradet project @UiO_ResearchMN @NASA_ICE @CopernicusEU
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@krisaalstad
Kristoffer Aalstad
1 year
@theAGU @norbert_nateko @spoton_fluxes @CbaOslo @NIVAforskning @UCPH_Research @NORCEresearch @NTNU @numpy_team Although the idea of Bayesian neural networks and training them with ensemble Kalman (or other MC) methods is not new, it is a promising way to conduct probabilistic machine learning (see the great books by @sirbayes) with uncertainty quantification that we need in (geo)science
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@krisaalstad
Kristoffer Aalstad
1 year
@theAGU @norbert_nateko @spoton_fluxes @CbaOslo @NIVAforskning @UCPH_Research @NORCEresearch @NTNU The "deep ensemble" neural network was trained without backpropagation using ensemble Kalman techniques from geophysical data assimilation to perform (approximate) Bayesian inference of network parameters implemented in pure @numpy_team code here
github.com
Contribute to norberp/deep_ensemble_flux_inference development by creating an account on GitHub.
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@krisaalstad
Kristoffer Aalstad
1 year
@theAGU @norbert_nateko @spoton_fluxes @CbaOslo @NIVAforskning @UCPH_Research @NORCEresearch @NTNU This was enabled by probabilistic machine learning by 1) Treating the network weights and biases as random variables and 2) Using a tailored network architecture with an aggregating likelihood induced by incorporating footprint weights in two output layers
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@krisaalstad
Kristoffer Aalstad
1 year
@theAGU @norbert_nateko @spoton_fluxes @CbaOslo @NIVAforskning @UCPH_Research @NORCEresearch @NTNU The headline result is that by combining a "deep ensemble" with a dynamic footprint model we are able to infer gap-free carbon dioxide and methane flux with uncertainty quantification from several surfaces (ponds, palsa, fen) from footprint-averaged eddy covariance data [Fig. 3]
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@CbaOslo
Centre for Biogeochemistry in the Anthropocene
1 year
Disaggregating the Carbon Exchange of Degrading Permafrost Peatlands Using Bayesian Deep Learning - Pirk - 2024 - Geophysical Research Letters - Wiley Online Library
Tweet card summary image
agupubs.onlinelibrary.wiley.com
Eddy covariance fluxes are disaggregated for different surfaces using Bayesian neural networks to derive uncertainty-aware carbon balances While palsa areas have a near-zero annual methane balanc...
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@rlmcelreath
Richard McElreath ๐Ÿˆโ€โฌ›
2 years
This talk (the Biblically accurate Bayesian -or- Bayes without Frequentist Language) was recorded and is available on the ytube now:
@rlmcelreath
Richard McElreath ๐Ÿˆโ€โฌ›
2 years
Making slides for a talk tomorrow โ€” This is a prompt to talk about the importance of showing problems in implementiing Bayesian workflows, not just successes
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@sirbayes
Kevin Patrick Murphy
2 years
Stanley's probability textbook ( https://t.co/QKOfdjV9jW) is fantastic, so I imagine this tutorial on diffusion is good as well. However, I am no longer of a fan of presenting the discrete time version - the flow matching interpretation seems more elegant.
@stanley_h_chan
Stanley H. Chan
2 years
I wrote a tutorial on diffusion models for undergrad and grad students. I tried my best to give intuitive explanations for complicated equations. Your feedback is much appreciated Thanks to those who suggested various reading materials to me https://t.co/fWv111nG5M
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@sp_monte_carlo
Sam Power
5 years
this week, i will tweet some textbook recommendations. for the books which i include, the basic criteria are that: 1) if i had found them earlier, i would have understood certain topics more quickly 2) they contributed to me liking the subject 3) i still enjoy reading them
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@sgascoin
Simon Gascoin
2 years
The SPOT satellites archive remains largely untapped. In this paper we show how to train a deep learning model to classify snow and clouds without reference data.. by emulating SPOT data from Sentinel-2 images. Unofficial name of the method: SPOTIFY. https://t.co/cXumvDgGnA
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@sirbayes
Kevin Patrick Murphy
2 years
To all who like this - what if I told you this book is not about the linear deterministic kind of SSM used by Mamba, S4, etc. but instead is about Bayesian inference in stochastic nonlinear dynamical models - would you still be interested?
@LeopolisDream
Alex Yanko ๐Ÿ‡บ๐Ÿ‡ฆ
2 years
State Space Models: A Modern Approach This is an interactive textbook on state space models (SSM) using the JAX Python library. https://t.co/GZSaypO2o6
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@Chiel1982
Chiel van Heerwaarden
2 years
By combining model development and observations from the @NWONieuws #SLOCS project and the @RuisdaelObserv, we created a cloud-resolving simulation with #MicroHH of The Netherlands with realistic boundary conditions derived from @ECMWF ERA5. Movie by @bartvstratum. @WUR.
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@krisaalstad
Kristoffer Aalstad
2 years
Working on data assimilation and inverse modeling for the terrestrial cryosphere? Consider applying to our EGU session @EuroGeosciences (deadline tomorrow!)
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@RDavy84
Richard Alan John Davy
2 years
Do you want to know what the snow conditions in Norway are forecast to be like in the coming months? Our downscaling of ECMWF forecasts are now live on the Arctic Portal: https://t.co/ph5AU6mRJS 6-month forecasts of snow depth and temperature will be updated every month.
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