Zhu et al. (2025) In-Flight Radiometric Calibration of Gas Absorption Bands for the Gaofen-5 (02) DPC Using Sunglint

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

Identification

• Journal: Remote Sensing
• Year: 2025
• Date: 2025-10-28
• Authors: Sifeng Zhu, Liguo Zhang, Yanqing Xie, Lili Qie, Zhengqiang Li, Miaomiao Zhang, Xiaochu Wang
• DOI: 10.3390/rs17213558

Research Groups

The paper focuses on the calibration of the Directional Polarimetric Camera (DPC) on the Gaofen-5 (02) satellite. While specific research groups, labs, or departments are not explicitly named, the work is characteristic of satellite remote sensing, atmospheric science, and instrument calibration teams, likely associated with national space agencies or research institutes involved in the Gaofen program.

Short Summary

This study presents a novel method for the in-flight radiometric calibration of gas absorption bands on the Gaofen-5 (02) satellite's Directional Polarimetric Camera (DPC), demonstrating robust performance with total uncertainties of 3.01% for oxygen and 3.45% for water vapor bands.

Objective

• To develop and validate a robust in-flight radiometric calibration method for the gas absorption bands of the Directional Polarimetric Camera (DPC) onboard the Gaofen-5 (02) satellite, addressing challenges posed by strong absorption features and the lack of onboard calibration devices.

Study Configuration

• Spatial Scale: Global applicability over sunglint regions, focusing on the spectral characteristics of the DPC instrument.
• Temporal Scale: In-flight calibration, designed for continuous or periodic application throughout the satellite's operational lifetime.

Methodology and Data

• Models used: Radiative transfer simulations, polynomial fitting.
• Data sources: Directional Polarimetric Camera (DPC) measurements from Gaofen-5 (02) satellite, prior knowledge of surface pressure, prior knowledge of water vapor column concentration, Digital Elevation Model (DEM)-derived estimates (for validation), MODIS total column water vapor products (for validation).

Main Results

• The calibration uncertainty for the oxygen absorption band is 3.01%, primarily driven by surface pressure.
• The calibration uncertainty for the water vapor absorption band is 3.45%, mainly influenced by water vapor column concentration and surface reflectance.
• The method's robustness was validated through: (1) cross-calibration using desert samples, confirming result stability; (2) agreement between retrieved surface pressure and DEM-derived estimates; and (3) agreement between retrieved total column water vapor and MODIS products.

Contributions

• Provides a novel and robust in-flight radiometric calibration method for gas absorption bands of the DPC on Gaofen-5 (02), overcoming the limitations of strong absorption features and the absence of onboard calibration devices.
• Establishes functional relationships between reflectance ratios of gas absorption and adjacent reference bands with key surface–atmosphere parameters over sunglint, leveraging radiative transfer simulations and polynomial fitting.
• Demonstrates high-precision calibration with quantified uncertainties for oxygen and water vapor bands, validated against independent data sources.
• The method is adaptable to similar satellite sensors with comparable spectral configurations, enhancing the utility of remote sensing data from such instruments.

Funding

• No specific funding projects, programs, or reference codes were mentioned in the provided paper text.

Citation

@article{Zhu2025InFlight,
  author = {Zhu, Sifeng and Zhang, Liguo and Xie, Yanqing and Qie, Lili and Li, Zhengqiang and Zhang, Miaomiao and Wang, Xiaochu},
  title = {In-Flight Radiometric Calibration of Gas Absorption Bands for the Gaofen-5 (02) DPC Using Sunglint},
  journal = {Remote Sensing},
  year = {2025},
  doi = {10.3390/rs17213558},
  url = {https://doi.org/10.3390/rs17213558}
}