CALIPSO lidar level 3 aerosol profile product: version 3 algorithm design

Area of Science:

• Atmospheric Science
• Remote Sensing
• Aerosol Science

Background:

• The CALIPSO satellite provides aerosol extinction profiles globally.
• Level 3 products aggregate monthly mean aerosol extinction profiles.
• Quality control is essential for reliable aerosol data products.

Purpose of the Study:

• To describe the quality screening and averaging methods for the CALIPSO Level 3 aerosol product (version 3).
• To evaluate the impact of various quality filters on aerosol extinction profiles and aerosol optical depth (AOD).
• To ensure the accuracy of globally gridded, monthly mean aerosol extinction profiles.

Main Methods:

• Utilized CALIOP Level 2 aerosol extinction profiles and layer classification data.
• Applied a series of quality filters to screen for layer detection, classification, retrieval errors, and surface signal anomalies.
• Calculated monthly mean AOD by vertically integrating quality-screened extinction profiles.

Main Results:

• The 'extinction QC flag' filter is most effective against high biases in mean extinction.
• The 'misclassified cirrus fringe' filter aggressively removes misclassified cirrus clouds.
• Quality screening reduced global ocean and land mean AOD by -24% and -31%, respectively.

Conclusions:

• Rigorous quality screening is vital for generating accurate CALIPSO Level 3 aerosol products.
• The implemented methods successfully mitigate various error sources, improving data reliability.
• The quality filters significantly reduce biases in monthly mean AOD, enhancing its scientific utility.