the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 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.
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Status: final response (author comments only)
- RC1: 'Comment on essd-2025-593', Anonymous Referee #1, 10 Nov 2025
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RC2: 'Comment on essd-2025-593', Anonymous Referee #2, 21 Nov 2025
Review comments on “A Global Black Carbon Dataset of Column Concentration and Microphysical Information Derived from MISR Multi-band Observations and Mie Scattering Simulation” by Liu et al. submitted to the journal Earth System Science Data.
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General comments:
This study by Liu et al. described an integrated method to estimate global BC mixing state, column concentration by using MISR VIS-NIR spectral SSA products with MIE calculation. The comparison with AERONET and MERRA-2 data show reliability of the developed method. The manuscript mainly focuses on the discussion about the >15 years global BC column concentration results. Overall, the topic is interesting. However, in my view, the manuscript still needs substantial improvements before it can be considered for publication.
The main concerns are as follows:
- The introduction and data description sections lack appropriate context and references. For example, Section 2.1 presents the MISR data on which the study heavily relies, yet it does not include a single reference. In addition, the description of MIE scattering in Section 2.2 is presented at a very general level and without any proper references. I don't see any connection with the method used in this study
- The most critical issue lies in the methodology section: the manuscript lacks a detailed description and evaluation of the methods used. As a result, the subsequent discussion of global BC column concentrations is not grounded on a sufficiently robust basis. For example, the refractive index of BC can significantly affect the derived column concentrations; however, the manuscript does not specify the key parameters used, such as the refractive index or particle density.
- In accordance with ESSD guidelines, the authors should include the generated dataset and its registered DOI in the abstract. Furthermore, the main text must provide a general overview of the data structure.
Specific comments:
L12: Multi-angle Imaging SpectroRadiometer (MISR)
L25-27: this statement is debatable according to the latest IPCC AR6
L32: secondary aerosol vapors? precursors?
L58-59: this is not the case for studies such as Li et al., 2019.
L64: -> have been proven
L75: what do you mean daily preprocessing?
L80: validate with MERRA-2 reanalysis seems to be the other way around.
Section 2.1: the first paragraph misses important references about MISR. The same for entire Section 2.1, it’s difficult for me to imagine that you used MISR data without citing any references.
L135-150: I find this section meaningless, as it is merely a repetition of the classical Mie theory. Reiterating this part does not seem to contribute to the study, and moreover, it does not include any references.
L153: retrievals are not observations
L160: I find out that there’s no discussions about MISR AAOD accuracy, the authors can easily validate MISR AAOD or SSA with AERONET.
L192: ±0.03 doesn’t mean the uncertainty of MISR SSA products used in your calculation, you’d better to evaluate or refer to specific MISR studies.
L198: I don’t find detailed description of about your method, and another key is how you assume BC refractive index?
Section 3.3: before in-depth discussion about the global BC results, I would see more about the method.
Citation: https://doi.org/10.5194/essd-2025-593-RC2
Data sets
Data from "A Global Black Carbon Dataset of Column Concentration and Microphysical Information Derived from MISR Muti-band Observations and Mie Scattering Simulations" (2004.10.1–2020.12.31) Zhewen Liu et al. https://figshare.com/s/2a2aa16468e874d42ab6
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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.