Zheng et al. (2025) Biases of Sentinel-5P and Suomi-NPP Cloud Top Height Retrievals: A Global Comparison

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Remote Sensing
• Year: 2025
• Date: 2025-10-24
• Authors: Zhe-Wen Zheng, Lechao Dong, Jie Yang, Qingxin Wang, Hao Lin, Siwei Li
• DOI: 10.3390/rs17213526

Research Groups

[Information not provided in the text.]

Short Summary

This study evaluates Sentinel-5P and Suomi-NPP Cloud Top Height (CTH) products against CloudSat/CALIPSO, revealing distinct and complementary systematic biases for different cloud types and layers, suggesting potential for improved CTH accuracy through product combination.

Objective

• To quantify systematic biases in Sentinel-5P (O2 A-band) and Suomi-NPP (thermal infrared) passive Cloud Top Height (CTH) products by comparing their global data against active CloudSat/CALIPSO reference data.

Study Configuration

• Spatial Scale: Global
• Temporal Scale: July 2018 to June 2019 (1 year)

Methodology and Data

• Models used: Sentinel-5P (S5P, O2 A-band) CTH retrieval, Suomi-NPP (NPP, thermal infrared) CTH retrieval.
• Data sources: Satellite-based passive remote sensing (Sentinel-5P, Suomi-NPP), Satellite-based active remote sensing (CloudSat/CALIPSO) as reference.

Main Results

• For single-layer liquid clouds over land, Sentinel-5P underestimates CTH while Suomi-NPP overestimates it, exhibiting opposing biases.
• For ice clouds, both Sentinel-5P and Suomi-NPP generally underestimate CTH, but Suomi-NPP demonstrates higher accuracy.
• In challenging two-layer cloud scenes, both retrieval methods show large systematic biases, with Sentinel-5P frequently erroneously detecting the lower cloud layer.
• The study reveals stark and complementary error patterns between the two passive CTH products.

Contributions

• Provides a quantitative evaluation of systematic biases in two prominent passive CTH products (Sentinel-5P and Suomi-NPP) using active CloudSat/CALIPSO as a global reference.
• Identifies distinct and complementary error characteristics across different cloud types (single-layer liquid, ice, two-layer) and land surfaces.
• Highlights the fundamental limitations inherent in single-sensor CTH retrievals.
• Reveals the potential for organically combining the advantages of different passive products to enhance overall CTH accuracy.

Funding

[Information not provided in the text.]

Citation

@article{Zheng2025Biases,
  author = {Zheng, Zhe-Wen and Dong, Lechao and Yang, Jie and Wang, Qingxin and Lin, Hao and Li, Siwei},
  title = {Biases of Sentinel-5P and Suomi-NPP Cloud Top Height Retrievals: A Global Comparison},
  journal = {Remote Sensing},
  year = {2025},
  doi = {10.3390/rs17213526},
  url = {https://doi.org/10.3390/rs17213526}
}