Global Above-Cloud Aerosol Optical Depth from CALIOP Satellite Lidar

Hiren Jethva presents a global dataset of above-cloud aerosol optical depth (ACAOD) retrieved using the Depolarization Ratio method applied to CALIOP lidar cloudy-sky measurements. The dataset was validated against airborne HSRL-2 lidar and 4STAR sun photometer measurements from the ORACLES field campaign in 2016–2018 and compared with Aqua-MODIS and OMI satellite retrievals. The data, last updated in May 2026, is shared under a CC-BY-4.0 license.

Use Cases

• Quantifying global aerosol loading over clouds based on the Depolarization Ratio method.
• Validating satellite aerosol retrievals against airborne lidar and sun photometer measurements.
• Estimating direct and semi-direct radiative effects of aerosols in cloudy atmospheres.
• Deriving extinction Ångström exponents to distinguish fine-mode smoke from coarse-mode dust aerosols.

Strengths

• Validation shows strong correlation with airborne measurements (R²∼0.95 for HSRL-2).
• Dataset is global in coverage, derived from CALIOP satellite measurements.
• Method does not require assumptions about detailed aerosol vertical profiles.

Limitations

• Dataset description is provided but specific columns and row counts are unknown.
• The DR method ACAOD shows an overall positive bias of ∼0.088 against airborne measurements.
• Data is provided in a DOCX file format, which may require extraction for analysis.

Provenance

Source

CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) instrument on the CALIPSO satellite.

Collection Method

Derived using the Depolarization Ratio method applied to CALIOP Level 2 cloud and aerosol layer products.

Freshness

Last updated 2026-05-29 11:50:14.

Geography

Global, with specific validation over the southeastern Atlantic Ocean.