CAL_MODIS_DTDB_ext_05km_V4-5_1 provides a global dataset of clear-sky aerosol extinction profiles, enabling improved assessments of aerosols' role in Earth’s climate and air quality systems. Derived from CALIOP data using MODIS Dark Target/Deep Blue (DT/DB) column aerosol optical depth (AOD, Collection 6), the dataset spans daytime observations over land and ocean between 2006 and 2018.   

Operational CALIOP aerosol extinction retrievals typically rely on lidar ratios, but uncertainties in these ratios create significant systematic errors (~30–50%). This dataset addresses these challenges by substituting lidar ratios with column-equivalent AODs, enabling the retrieval of aerosol extinction profiles from CALIOP attenuated backscatter data.   

Validation against more than 150 coincident airborne High Spectral Resolution Lidar (HSRL) datasets demonstrates strong agreement, with mean bias differences within 0.01 km⁻¹ (10%). The constrained profiles outperform CALIOP V4.51 operational retrievals, reducing both bias and root-mean-square differences by nearly a factor of two.   

These constrained CALIOP aerosol extinction profiles are valuable for various applications, including estimating PM2.5 concentrations and reducing uncertainties in aerosol radiative forcing.