Portrait of Paula Harder

Paula Harder

Independent visiting researcher
Supervisor
David Rolnick
Research Topics
Climate Change AI
Climate Modeling
Climate Science
Climate Variable Downscaling
Deep Learning
Machine Learning and Climate Change
Machine Learning in Climate Modeling
Website
Google Scholar
GitHub

Publications

RainShift: A Benchmark for Precipitation Downscaling Across Geographies
Paula Harder
Luca Schmidt
Francis Pelletier
Nicole Ludwig 0002
Matthew Chantry
Christian Lessig
Alex Hernandez-Garcia
David Rolnick
Earth System Models (ESM) are our main tool for projecting the impacts of climate change. However, running these models at sufficient resolu… (see more)tion for local-scale risk-assessments is not computationally feasible. Deep learning-based super-resolution models offer a promising solution to downscale ESM outputs to higher resolutions by learning from data. Yet, due to regional variations in climatic processes, these models typically require retraining for each geographical area-demanding high-resolution observational data, which is unevenly available across the globe. This highlights the need to assess how well these models generalize across geographic regions. To address this, we introduce RainShift, a dataset and benchmark for evaluating downscaling under geographic distribution shifts. We evaluate state-of-the-art downscaling approaches including GANs and diffusion models in generalizing across data gaps between the Global North and Global South. Our findings reveal substantial performance drops in out-of-distribution regions, depending on model and geographic area. While expanding the training domain generally improves generalization, it is insufficient to overcome shifts between geographically distinct regions. We show that addressing these shifts through, for example, data alignment can improve spatial generalization. Our work advances the global applicability of downscaling methods and represents a step toward reducing inequities in access to high-resolution climate information.
2025-07-01
arXiv (published)
doi.org
arxiv.org
Evaluating the transferability potential of deep learning models for climate downscaling
Ayush Prasad
Paula Harder
Qidong Yang
Prasanna Sattegeri
Daniela Szwarcman
Campbell Watson
David Rolnick
Climate downscaling, the process of generating high-resolution climate data from low-resolution simulations, is essential for understanding … (see more)and adapting to climate change at regional and local scales. Deep learning approaches have proven useful in tackling this problem. However, existing studies usually focus on training models for one specific task, location and variable, which are therefore limited in their generalizability and transferability. In this paper, we evaluate the efficacy of training deep learning downscaling models on multiple diverse climate datasets to learn more robust and transferable representations. We evaluate the effectiveness of architectures zero-shot transferability using CNNs, Fourier Neural Operators (FNOs), and vision Transformers (ViTs). We assess the spatial, variable, and product transferability of downscaling models experimentally, to understand the generalizability of these different architecture types.
2024-07-17
ArXiv (preprint)
doi.org
arxiv.org
Evaluating the transferability potential of deep learning models for climate downscaling
Ayush Prasad
Paula Harder
Qidong Yang
Prasanna Sattegeri
D. Szwarcman
Campbell Watson
David Rolnick
Climate downscaling, the process of generating high-resolution climate data from low-resolution simulations, is essential for understanding … (see more)and adapting to climate change at regional and local scales. Deep learning approaches have proven useful in tackling this problem. However, existing studies usually focus on training models for one specific task, location and variable, which are therefore limited in their generalizability and transferability. In this paper, we evaluate the efficacy of training deep learning downscaling models on multiple diverse climate datasets to learn more robust and transferable representations. We evaluate the effectiveness of architectures zero-shot transferability using CNNs, Fourier Neural Operators (FNOs), and vision Transformers (ViTs). We assess the spatial, variable, and product transferability of downscaling models experimentally, to understand the generalizability of these different architecture types.
2024-07-17
ArXiv (preprint)
doi.org
arxiv.org
Climate Variable Downscaling with Conditional Normalizing Flows
Christina Winkler
Paula Harder
David Rolnick
Predictions of global climate models typically operate on coarse spatial scales due to the large computational costs of climate simulations.… (see more) This has led to a considerable interest in methods for statistical downscaling, a similar process to super-resolution in the computer vision context, to provide more local and regional climate information. In this work, we apply conditional normalizing flows to the task of climate variable downscaling. We showcase its successful performance on an ERA5 water content dataset for different upsampling factors. Additionally, we show that the method allows us to assess the predictive uncertainty in terms of standard deviation from the fitted conditional distribution mean.
2024-05-31
ArXiv (preprint)
doi.org
arxiv.org
Multi-variable Hard Physical Constraints for Climate Model Downscaling
Jose Gonz'alez-Abad
'Alex Hern'andez-Garc'ia
Paula Harder
David Rolnick
Jos'e Manuel Guti'errez
2023-08-02
ArXiv (preprint)
doi.org
arxiv.org
Fourier Neural Operators for Arbitrary Resolution Climate Data Downscaling
Qidong Yang
Alex Hernandez-Garcia
Paula Harder
Venkatesh Ramesh
Prasanna Sattegeri
D. Szwarcman
Campbell Watson
David Rolnick
Climate simulations are essential in guiding our understanding of climate change and responding to its effects. However, it is computational… (see more)ly expensive to resolve complex climate processes at high spatial resolution. As one way to speed up climate simulations, neural networks have been used to downscale climate variables from fast-running low-resolution simulations, but high-resolution training data are often unobtainable or scarce, greatly limiting accuracy. In this work, we propose a downscaling method based on the Fourier neural operator. It trains with data of a small upsampling factor and then can zero-shot downscale its input to arbitrary unseen high resolution. Evaluated both on ERA5 climate model data and on the Navier-Stokes equation solution data, our downscaling model significantly outperforms state-of-the-art convolutional and generative adversarial downscaling models, both in standard single-resolution downscaling and in zero-shot generalization to higher upsampling factors. Furthermore, we show that our method also outperforms state-of-the-art data-driven partial differential equation solvers on Navier-Stokes equations. Overall, our work bridges the gap between simulation of a physical process and interpolation of low-resolution output, showing that it is possible to combine both approaches and significantly improve upon each other.
2023-05-23
ArXiv (preprint)
doi.org
arxiv.org