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An animation worth copying Pierre Chevillard posted an animation for France's slice of tomorrow's eclipse: a map dotted with cities, each one carrying a small icon of the Sun with the Moon's black disc sliding across it, ticking forward through the evening in sync with a clock in the corner. It's a nice piece of graphic design and, underneath it, a fairly approachable computation. This post…
A continental heatwave chart, zoomed down to one city with DANRA It's been a brutal summer. Barely a week has gone by in 2026 without another heat warning, another wildfire evacuation, another all-time record somewhere in Western Europe. Heatwaves have been in the news a lot lately, and this year the coverage doesn't feel like a series of one-off events so much as a pattern that's settled in. A…
It sounds a bit strange at first: the same satellite signals used for positioning can also tell us something about rain. When GNSS signals travel from a satellite to a receiver on the ground, they are delayed by the atmosphere. Part of that delay comes from water vapour (see one of my old postst here ) If the atmosphere above a station becomes rapidly moister before a convective event, the…
If you know Seinfeld , you may remember the episode "The Butter Shave," where Puddy spends a long flight simply staring at the seat in front of him. Elaine cannot understand it. "Do you want something to read?" she asks. Puddy replies, "No, I'm good." The joke is that Puddy seems vacant, as if only a dull person could sit there without reaching for a book, a screen, or some other distraction. But…
GNSS Signal Delays and Atmospheric Information Every time you glance at your smartphone to navigate a city street or check your car's "GPS", you are participating in a feat of modern geodesy. To determine your position with the centimeter-level accuracy we now take for granted, a satellite signal must traverse thousands of miles of the Earth’s atmosphere. Historically, this journey was a technical…
Today marks the official release of a project I’ve been working hard on over the past few months: the next generation of the Copernicus Arctic Regional Reanalysis CARRA . This new system, CARRA2, extends coverage to the entire pan-Arctic domain north of 60°N and will span all years from 1986 to 2025. The complete dataset is planned for release in 2026. CARRA2 domain, compared to CARRA1 (East and…
Introduction In a previous post , we developed a simple model to forecast solar power generation. However, we identified a critical shortcoming: the model did not account for the growth in installed solar capacity over time. This resulted in a forecast that was likely too low. This post presents an improved approach that attempts to address this issue. The main idea is to model the capacity growth…
Introduction This blog post outlines a first attempt to forecast hourly solar power generation in Germany for June 2025. This is a highly condensed version of the project described in this git repository , where the whole process is presented in detail in a series of quarto notebooks. Data Overview We have two main datasets: one with hourly solar power generation observations and another with…
I recently participated in the production of DANRA , a high-resolution regional reanalysis for Denmark that was just released. Working on this project gave me a deeper appreciation for what reanalyses are and why they matter. DANRA covers 34 years of Danish weather at 2.5 km resolution, capturing everything from the devastating December 1999 hurricane-force storm to the July 2022 national…
I was once given a week to build a machine learning model to predict solar power as part of a job application for a meteorological data scientist role. And guess what? I worked on this task for most of that week, writing Quarto notebooks (a more fancy way to write Jupyter notebooks) and documenting all the steps in a githhub repo like it owed me money. No distractions, no excuses. But then, when…