  Clouds play a crucial role in the Earth's water and energy cycles,
underscoring the importance of high spatiotemporal resolution data on cloud
phase and properties for accurate numerical modeling and weather prediction.
Currently, Moderate Resolution Imaging Spectroradiometer (MODIS) provides cloud
products with a spatial resolution of 1 km. However, these products suffer from
a lengthy revisit cycle. This study develops a generative diffusion model
(donated as CloudDiff) for super-resolution retrieval of high spatiotemporal
cloud phase and properties, applicable both day and night. Leveraging 2 km
spatial resolution Himawari-8 Advanced Himawari Imager (AHI) thermal infrared
(TIR) radiances and viewing geometry as condition, alongside daytime MODIS
products as targets, the model can generate cloud phase (CLP), cloud top height
(CTH), cloud optical thickness (COT), and cloud effective radius (CER) at 1 km
spatial resolution and 10-minute temporal resolution. The conditional diffusion
model can generate sharper images and capture finer local features than
deterministic super-resolution approaches. It draws multiple samples based on
the underlying probability distribution, enabling retrieval uncertainty
assessment. Evaluations show agreement between cloud phase and properties
derived from the CloudDiff and MODIS cloud products. The ensemble mean is found
to enhance retrieval accuracy and credibility, outperforming the deterministic
model.
