Prithvi WxC: Foundation Model for Weather and Climate
Authors: name: Johannes Schmude, name: Sujit Roy, name: Will Trojak, name: Johannes Jakubik, name: Daniel Salles Civitarese, name: Shraddha Singh, name: Julian Kuehnert, name: Kumar Ankur, name: Aman Gupta, name: Christopher E Phillips, name: Romeo Kienzler, name: Daniela Szwarcman, name: Vishal Gaur, name: Rajat Shinde, name: Rohit Lal, name: Arlindo Da Silva, name: Jorge Luis Guevara Diaz, name: Anne Jones, name: Simon Pfreundschuh, name: Amy Lin, name: Aditi Sheshadri, name: Udaysankar Nair, name: Valentine Anantharaj, name: Hendrik Hamann, name: Campbell Watson, name: Manil Maskey, name: Tsengdar J Lee, name: Juan Bernabe Moreno, name: Rahul Ramachandran

Triggered by the realization that AI emulators can rival the performance of
traditional numerical weather prediction models running on HPC systems, there
is now an increasing number of large AI models that address use cases such as
forecasting, downscaling, or nowcasting. While the parallel developments in the
AI literature focus on foundation models -- models that can be effectively
tuned to address multiple, different use cases -- the developments on the
weather and climate side largely focus on single-use cases with particular
emphasis on mid-range forecasting. We close this gap by introducing Prithvi
WxC, a 2.3 billion parameter foundation model developed using 160 variables
from the Modern-Era Retrospective Analysis for Research and Applications,
Version 2 (MERRA-2). Prithvi WxC employs an encoder-decoder-based architecture,
incorporating concepts from various recent transformer models to effectively
capture both regional and global dependencies in the input data. The model has
been designed to accommodate large token counts to model weather phenomena in
different topologies at fine resolutions. Furthermore, it is trained with a
mixed objective that combines the paradigms of masked reconstruction with
forecasting. We test the model on a set of challenging downstream tasks namely:
Autoregressive rollout forecasting, Downscaling, Gravity wave flux
parameterization, and Extreme events estimation. The pretrained model with 2.3
billion parameters, along with the associated fine-tuning workflows, has been
publicly released as an open-source contribution via Hugging Face.