arXiv:2503.13316physics.ao-phcs.AI2025-03被引 3

用生成对抗网络提升降水数据分辨率,还原真实分布特征。

RainScaleGAN: a Conditional Generative Adversarial Network for Rainfall Downscaling

  • 基于条件卷积GAN,从低分辨率降水数据重建高分辨率图像。
  • 在理想模型测试中优于现有主流降尺度方法,还原度接近真实数据。
  • 不依赖物理机制,可推广至风速、温度等其他气象变量。

当前准确模拟局地降水并可靠再现其分布仍具挑战,主要受限于全球气候模型的水平分辨率。极端降水事件的物理机制在时空尺度上小于模型数值解析范围,难以被精确捕捉。为克服此限制,过去几十年发展了多种降尺度方法以弥合模型输出与局地应用所需分辨率之间的差距。本文提出RainScaleGAN,一种用于降水降尺度的条件深度卷积生成对抗网络。由于生成对抗网络在图像超分辨率任务中表现优异,该方法对降尺度任务高度适用。在理想模型设置下,将0.25°×0.25°的降水数据人为降采样至2°×2°,再使用RainScaleGAN进行恢复。结果表明,所提模型在性能上超过文献中领先的降水降尺度方法。RainScaleGAN不仅能生成符合真实高分辨率空间模式和强度的合成数据集,还能使降水统计分布与真实数据高度一致。由于该方法对底层物理机制无依赖性,未来有望扩展应用于地表风速、温度等其他物理变量的降尺度任务。

原文摘要 · Abstract (English)

To this day, accurately simulating local-scale precipitation and reliably reproducing its distribution remains a challenging task. The limited horizontal resolution of Global Climate Models is among the primary factors undermining their skill in this context. The physical mechanisms driving the onset and development of precipitation, especially in extreme events, operate at spatio-temporal scales smaller than those numerically resolved, thus struggling to be captured accurately. In order to circumvent this limitation, several downscaling approaches have been developed over the last decades to address the discrepancy between the spatial resolution of models output and the resolution required by local-scale applications. In this paper, we introduce RainScaleGAN, a conditional deep convolutional Generative Adversarial Network (GAN) for precipitation downscaling. GANs have been effectively used in image super-resolution, an approach highly relevant for downscaling tasks. RainScaleGAN's capabilities are tested in a perfect-model setup, where the spatial resolution of a precipitation dataset is artificially degraded from 0.25$^{\circ}\times$0.25$^{\circ}$ to 2$^{\circ}\times$2$^\circ$, and RainScaleGAN is used to restore it. The developed model outperforms one of the leading precipitation downscaling method found in the literature. RainScaleGAN not only generates a synthetic dataset featuring plausible high-resolution spatial patterns and intensities, but also produces a precipitation distribution with statistics closely mirroring those of the ground-truth dataset. Given that RainScaleGAN's approach is agnostic with respect to the underlying physics, the method has the potential to be applied to other physical variables such as surface winds or temperature.

降水降尺度生成对抗网络气候建模

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