| 07 Oct 2025
A Global Black Carbon Dataset of Column Concentration and Microphysical Information Derived from MISR Multi-band Observations and Mie Scattering Simulations
Abstract. Black carbon, a major absorbing component of atmospheric aerosols, plays an important role in climate regulation, air quality, and human health, yet its column concentration and microphysical properties at regional and global scales remains highly uncertain. In this study, we implement an integrated approach that combines multi-angle, multi-band observations from the Multi-angle Imaging SpectroRadiometer with a Mie scattering framework to estimate black carbon column properties including size and mixing state globally on a daily basis. By constraining particle size distributions with absorption aerosol optical depth and single scattering albedo across all four bands, the method simultaneously retrieves number and mass concentrations. Long-term simulations from 2005 to 2020 reveal distinct spatial and temporal patterns, with particularly high levels over biomass burning regions in Africa and South America as well as industrial and urban centers in Asia. Comparisons with ground-based sun photometer measurements and reanalysis data confirm the robustness and accuracy of the estimates. The resulting dataset provides a consistent global record of black carbon column concentrations, offering valuable support for constraining climate models, improving assessments of aerosol radiative forcing, and informing targeted mitigation strategies.
General Comments: Liu et al. processed 16 years of MISR Level-3 aerosol products to derive global black carbon (BC) information, including its column concentration and microphysical properties, based on a theoretical Mie model. The authors developed the new dataset to support investigations of the spatial and temporal variations of BC concentrations and emissions at both global and regional scales. Comparisons with AERONET observations and MERRA-2 model products are valuable additions that help demonstrate the dataset’s performance.
Specific comments:
However, several major issues need to be addressed before the manuscript can be considered for publication, even prior to providing more specific comments. Overall, the current manuscript compiles a large amount of information without clear organization or illustration, which significantly reduces its readability and scientific value. Therefore, the paper requires substantial restructuring to clearly separate each section.
At present, much of the introductory and methodological content is misplaced within the Results section, while the Discussion section mixes results with interpretation.
Recommend reorganizing the manuscript so that all methodological descriptions are moved to the Methods section, and all results are presented in the Results section, and relevant interpretations and implications are discussed in the Discussion section. The authors can also follow the structure and presentation style of other published ESSD data papers to effectively demonstrate their dataset and provide illustrative examples.
The Methodology section, needs significant improvement. In addition to relocating relevant content from the Results section, the authors should provide detailed explanations of the equations used, explicitly listing and defining all key variables. Without these details, the equations appear as disconnected expressions without clear purpose or interpretability. Furthermore, the procedures for spatial and temporal aggregation of the MISR product should be clearly described, and the QA/QC processes for the MISR L3 aerosol data must be clarified, including an assessment of associated uncertainties. The uncertainties associated with AERONET and MERRA-2 estimates should also be carefully discussed.
Finally, the description of the new dataset should be more comprehensive. The authors need to clearly specify the data structure, file format, and accessibility. For example, if the dataset is mainly provided in “.mat” format, they should offer example MATLAB scripts or guidance for reading and visualizing the data.
Overall, I recommend that the authors substantially revise and better structure the manuscript before it can be further considered for publication.