HiRO-ACEv2
Ai2's climate emulator pairing 100 km ACE with a HiROv2 downscaler to produce global 3 km data at ~1/300th the cost of X-SHiELD.
Overview
HiRO-ACEv2, published by Ai2 on October 14, 2026, updates the High Resolution Output Ai2 Climate Emulator by pairing ACE, a ~100 km climate model, with HiROv2, which downscales to 3 km. HiROv2 now predicts several high-resolution fields at once rather than only rainfall and has better skill on extreme events. Ai2 reports it matches target high-resolution statistics within 3% on coarsened X-SHiELD data and generates global 3 km data for roughly 1/300th of the cost of running X-SHiELD. It currently works only with the ACE version tuned to X-SHiELD, so it cannot yet produce warmer-future or ERA5-style data.
This is a sourced directory entry. Features and capabilities are reported in the linked sources; this entry does not document independent Aymorphic testing.
Key features
- ACE (~100 km) plus HiROv2 downscaling to 3 km output
- Multiple output fields instead of rainfall only
- Statistics within 3% of X-SHiELD targets, including very rare extremes (Ai2-reported)
- Global 3 km data at roughly 1/300th of X-SHiELD compute cost
- Weights at allenai/HiRO-ACEv2 on Hugging Face; paper arXiv 2610.17693; tutorial notebooks and web demo at ace.allen.ai
- Known limits: X-SHiELD-tuned only; hurricane winds and pressure near the eye somewhat more lopsided
Use cases
- Generating fine-scale regional climate and extreme-weather datasets
- Estimating tropical cyclone energy statistics at low compute cost
Pricing
Open weights on Hugging Face; license not stated in the announcement.
Pricing reflects the source record and may change. Confirm current terms with the provider.
Dates and sources
- Released
- 14 Oct 2026
- Record updated
- 19 Oct 2026
- Record last checked
- 19 Oct 2026