# FuXi-CFD Dataset

## Overview

This dataset accompanies the paper:

**Reconstructing fine-scale 3D wind fields with terrain-informed machine learning**

It contains large-scale CFD-generated wind field simulations used for training and evaluating the FuXi-CFD model described in the paper.

The dataset includes over **12,000 cases**.  

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## Dataset Organization

The dataset is distributed as compressed archive files:

FuXi-CFD-dataset-part01.tar  
FuXi-CFD-dataset-part02.tar  
...  
FuXi-CFD-dataset-part13.tar  

Each case follows the structure:

case_000001/  
    inputs.npz  
    outputs.npz  

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## Inputs (inputs.npz)

The `inputs.npz` file contains four variables:

### dem

- Shape: (300, 300)  
- Unit: meters (m)  
- Horizontal resolution: 30 m  

Digital Elevation Model (DEM) representing terrain elevation.

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### roughness

- Shape: (300, 300)  
- Unit: meters (m)  
- Horizontal resolution: 30 m  

Surface roughness length (z₀) map representing aerodynamic terrain roughness.

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### u_100m

- Shape: (9, 9)  
- Unit: m s⁻¹  
- Horizontal resolution: approximately 1 km  

Coarse-resolution zonal wind component at 100 m height.

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### v_100m

- Shape: (9, 9)  
- Unit: m s⁻¹  
- Horizontal resolution: approximately 1 km  

Coarse-resolution meridional wind component at 100 m height.

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## Outputs (outputs.npz)

The `outputs.npz` file contains four high-resolution 3D variables.

All output variables have shape:

(27, 300, 300)

where:

- 27 corresponds to the number of vertical levels (in meters above ground level).
- 300 × 300 corresponds to 30 m horizontal resolution  

The 27 vertical levels are:

5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100,  
106.5, 114.95, 125.94, 140.22, 158.78, 182.91, 214.29

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### u

- Unit: m s⁻¹  

Zonal wind component (east–west).

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### v

- Unit: m s⁻¹  

Meridional wind component (north–south).

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### w

- Unit: m s⁻¹  

Vertical wind component.

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### k

- Unit: m² s⁻²  

Turbulent kinetic energy (TKE).

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## Resolution Summary

| Variable       | Horizontal Resolution | Vertical Levels |
| -------------- | --------------------- | --------------- |
| dem            | 30 m                  | —               |
| roughness      | 30 m                  | —               |
| u_100m, v_100m | 1 km                  | single level    |
| u, v, w, k     | 30 m                  | 27 levels       |

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## Data Split

The dataset is provided as a single collection without predefined splits.

The official train/validation/test split used in the paper can be found in the associated publication.

Users are free to define custom splits for their own applications.

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## License

CC BY-NC 4.0

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## Citation

If you use this dataset, please cite:

Lin, C., et al. *Reconstructing fine-scale 3D wind fields with terrain-informed machine learning*, Nature Communications (2026).