| 06 Jan 2026
Radiative Influence of Dust Aerosols on the Evolution of Tropical Storm Hermine
Abstract. This study investigates the impact of dust aerosols on the evolution of Tropical Storm Hermine (2022) using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and observational data from the NASA Convective Processes Experiment – Cabo Verde (CPEX-CV). The objective is to evaluate how varying initial dust aerosol conditions influence storm development and to uncover the mechanisms behind these effects. Three WRF-Chem simulations were conducted with different initial aerosol concentrations: one with no aerosols, one with realistic dust concentrations, and one with intermediate aerosol levels. The simulations were compared against observational data from CPEX-CV and the best track data from the United States' National Hurricane Centre, focusing on parameters such as wind, pressure, aerosol optical depth, and radar reflectivity. The results indicate that the radiative effect of dust aerosols led to a weaker and more disorganized storm system compared to simulations without the inclusion of dust, highlighting the critical role of dustradiation interactions in modifying storm intensity. Furthermore, the study found that the ECMWF's Atmospheric Composition Reanalysis 4 (CAMS) underestimated atmospheric dust concentrations, in comparisons to observations, underlining the necessity for accurate observational data to validate aerosol-related processes and improve model predictions. These findings emphasize the complexity of dust aerosol-storm interactions and the importance of improving aerosol representations in simulations of tropical cyclones.
This study uses WRF-Chem to investigate the radiative impact of Saharan dust on Tropical Storm Hermine (2022), utilizing NASA CPEX-CV observations for model initiation and validation. While the application of a fully-coupled model to this event is appreciated, the manuscript needs major revisions before it can be published.
The whole story is not clear:
1) The title is “radiative influence”, but the paper does not effectively distinguish between radiation and microphysical effects. When using a model like WRF-Chem with MOSAIC, these effects often occur simultaneously without a methodological framework to distinguish between the two. And in some parts of results and discussion, the authors explicitly explain through the “dust’s role as effective cloud condensation and ice nuclei”.
2) It is not clear how the study advances over previous work. The Introduction mentions that “Despite decades of study, the net effect of Saharan dust on TC development is not fully resolved”; yet the title of this study is only on “radiative influence”. Also, Results and Discussion currently reconfirm existing studies without offering new insights into dust-TC interactions. The Introduction feels like a literature review that doesn't link to the specific gaps this study tries to fill. Similarly, the abstract focuses more on the summary of results than on the contribution and novelty.
3) The way that the observation-like dust aerosols are simulated is not very convincing. Why does doubling the initial conditions and mapping coefficients result in a consistent doubling of concentration? As the authors didn’t explicitly compare the reanalysis CAMS and observation-based CPEX-CV, the “50% underestimation in dust loading” is vague, without knowing which variable (AOD, extinction, mass) or which height/time was compared. This undermines the credibility of the setup for the Extra simulation as well. Moreover, is the “50% underestimation in CAMS” one of the results or just background information? It is written in the supposed result part in the abstract, but then in the Introduction without further elaboration in the Results.
4) The Results section is organized in a confusing way. Why put dust concentrations as the first section, as the simulations were set up according to different levels of concentration? Also, the third section is titled "Radiative and thermodynamic effects," but since the whole paper is about this, that title should be automatically a top-level theme, not a small sub-section.
5) The section on “track differences” is too short and not well explained. The authors are conflating Experimental Design with Physical Results. “The tracks remained geographically close throughout, minimizing environmental variability.” This is like a justification for the experimental design. But here, it is supposed to be the results. As a reader, we want to know what this means to the effect of dust aerosol on the storm. Is it because Hermine was a weak system dominated by strong background flow? Or because the radiative forcing of the dust was too weak to alter the storm's vertical tilt?
6) The Discussion is largely repeating the Results, without providing any new insights into the knowledge level. It’s hard to see how this paper advances beyond previous knowledge.
7) The figures need a lot of improvement. Current figures look like raw model output rather than scientific illustrations. 15 figures are too many, and they don't tell a coherent story. For example, in Fig. 3, the x-axis "Distance Along Flight Path" has no meteorological meaning. This is a human-defined trajectory, not a natural coordinate; how does it actually relate to the distance from the storm center, or anything meaningful? Besides, many figures have very small fonts, titles that overflow, and repetitive wording.
8) For the overall manuscript, especially Results and Discussion, the topic sentences do not stand out, and the paragraphs are not well organized, making it hard to capture the core messages.
Specific comments:
L187: “driven by radiation changes”. How and what kind of changes? Not clearly stated.
L268: confused. Why “track comparisons” can ensure “similar environmental conditions”? It is usually the other way around.
Fig.3: What does the white space mean in the top panel? If there is no data, it should be stated. I am not convinced that the "Extra" run correctly captures the vertical plume based on this plot.