Berkshire
Enhancing AI and Dynamical Subseasonal Forecasts with Probabilistic Bias Correction
Guan, Hannah, Mouatadid, Soukayna, Orenstein, Paulo, Cohen, Judah, Dong, Haiyu, Ni, Zekun, Berman, Jeremy, Flaspohler, Genevieve, Lu, Alex, Schloer, Jakob, Talib, Joshua, Weyn, Jonathan A., Mackey, Lester
Decision-makers rely on weather forecasts to plant crops, manage wildfires, allocate water and energy, and prepare for weather extremes. Today, such forecasts enjoy unprecedented accuracy out to two weeks thanks to steady advances in physics-based dynamical models and data-driven artificial intelligence (AI) models. However, model skill drops precipitously at subseasonal timescales (2 - 6 weeks ahead), due to compounding errors and persistent biases. To counter this degradation, we introduce probabilistic bias correction (PBC), a machine learning framework that substantially reduces systematic error by learning to correct historical probabilistic forecasts. When applied to the leading dynamical and AI models from the European Centre for Medium-Range Weather Forecasts (ECMWF), PBC doubles the subseasonal skill of the AI Forecasting System and improves the skill of the operationally-debiased dynamical model for 91% of pressure, 92% of temperature, and 98% of precipitation targets. We designed PBC for operational deployment, and, in ECMWF's 2025 real-time forecasting competition, its global forecasts placed first for all weather variables and lead times, outperforming the dynamical models from six operational forecasting centers, an international dynamical multi-model ensemble, ECMWF's AI Forecasting System, and the forecasting systems of 34 teams worldwide. These probabilistic skill gains translate into more accurate prediction of extreme events and have the potential to improve agricultural planning, energy management, and disaster preparedness in vulnerable communities.
Human brain cells on a chip learned to play Doom in a week
A clump of human brain cells can play the classic computer game . While its performance is not up to par with humans, experts say it brings biological computers a step closer to useful real-world applications, like controlling robot arms. In 2021, the Australian company Cortical Labs used its neuron-powered computer chips to play . The chips consisted of clumps of more than 800,000 living brain cells grown on top of microelectrode arrays that can both send and receive electrical signals. Researchers had to carefully train the chips to control the paddles on either side of the screen.
Is texting behind the wheel of a self-driving Tesla crazy?
Is texting behind the wheel of a self-driving Tesla crazy? As self-driving cars get closer to reality, Tesla is striving to remain a big player. But is it sacrificing safety to stay in the game? For the past few weeks, Geoff Perlman, a 61-year-old technology executive from Texas, has been testing a free trial of Tesla's latest self-driving software as he travels around Austin. He's impressed: it can handle confusing lane adjustments and park itself in busy lots better, he thinks, than the average human.
Blade: A Derivative-free Bayesian Inversion Method using Diffusion Priors
Zheng, Hongkai, Wang, Austin, Wu, Zihui, Huang, Zhengyu, Baptista, Ricardo, Yue, Yisong
Derivative-free Bayesian inversion is an important task in many science and engineering applications, particularly when computing the forward model derivative is computationally and practically challenging. In this paper, we introduce Blade, which can produce accurate and well-calibrated posteriors for Bayesian inversion using an ensemble of interacting particles. Blade leverages powerful data-driven priors based on diffusion models, and can handle nonlinear forward models that permit only black-box access (i.e., derivative-free). Theoretically, we establish a non-asymptotic convergence analysis to characterize the effects of forward model and prior estimation errors. Empirically, Blade achieves superior performance compared to existing derivative-free Bayesian inversion methods on various inverse problems, including challenging highly nonlinear fluid dynamics.
FNP: Fourier Neural Processes for Arbitrary-Resolution Data Assimilation
Data assimilation is a vital component in modern global medium-range weather forecasting systems to obtain the best estimation of the atmospheric state by combining the short-term forecast and observations. Recently, AI-based data assimilation approaches have attracted increasing attention for their significant advantages over traditional techniques in terms of computational consumption.