HiRO-ACEv2: Simulating extreme weather at 3 km resolution for a fraction of the cost

Summary

HiRO-ACEv2 generates global 3 km climate data for extreme weather at roughly 1/300th the cost of the X-SHiELD model, with even larger savings for single-region runs. The system pairs a coarse 100 km AI model (ACE) with the new HiROv2 downscaler that simultaneously predicts rain, wind, and sea-level pressure instead of just rainfall, and has improved skill at reproducing extreme events. When fed coarsened X-SHiELD data HiROv2 matches the target’s high-resolution statistics within 3% for events as rare as one in a million data points, and accurately estimates tropical cyclone energy for storms never seen during training. Over a 10-year simulation the full system’s hurricane energy and extreme event snapshots compare well with X-SHiELD. However, HiRO cannot yet handle other climates because it depends on X-SHiELD-specific ACE tuning; future work includes training on warmer-world datasets and adding temperature and snow outputs.

Takeaways

1. 1

   HiROv2 can predict multiple high-resolution fields (precipitation, wind, sea-level pressure) simultaneously, improving upon the single-field output of HiROv1.

2. 2

   When using coarsened X-SHiELD as input, HiROv2 matches the target high-resolution statistics to within 3% for events as rare as one in a million data points.

3. 3

   The full HiRO-ACEv2 system generates global 3 km climate data at roughly 1/300th the cost of X-SHiELD; savings are even greater for single-region simulations.

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