Brown carbon (BrC) is an important component of aerosols in the atmosphere, and there are still significant uncertainties on their chemistry and physical properties as well as their influences on the atmosphere. This manuscript presents an observationally-constrained approach to estimate the radiative effects of BrC aerosols using routine ground-based measurements, and offers a convenient method to assess the climate impacts of BrC. This study effectively integrates observations, optical computations, and radiative transfer models. By employing optical closure techniques, the radiative effects of black carbon were isolated. This approach proves to be both straightforward and efficacious. Meanwhile, by considering only the conventional observations and numerical models, the framework of the proposed method shows great potential for further studies. Overall, the study is well motivated and adds to our understanding of BrC effects. There are several areas that need clarification or revision prior to publication.

1. More details could be provided on the observations used to constrain the analysis. In particular, the authors should specify details such as the sampling time period and measurement frequency for each instrument.

2. From the perspective of content relevance, it appears more appropriate to position Figure 1 and its associated description within the Section 2 rather than the third section.

3. Figure 2 serves as a comprehensive overview of the proposed methodology, playing a pivotal role in the exposition of this paper. To provide a clearer understanding, additional space to elucidate the details within Figure 2 is suggested, including the calculation methods for parameters such as MAC (Mass Absorption Coefficient). Alternatively, to manage space constraints, specific algorithms for each subsection of Figure 2 can be referenced in the subsequent sections of this paper.

4. Figure 4 indicates that the imaginary part of BrC refractive indices may differ over two orders of magnitudes. Would such variation introduce additional uncertainties on the results of this study?

5. In Figure 5, the label “LSC/10” is confusion. 

6. More discussions on regarding the applicability of the method and the generalizability of the results are suggested, and the limitations of the method could also be discussed. 

7. It is advisable to further imrpove the figures qualities. For instance, the tick labels in Figure 4 appear relatively small and could benefit from a consistent font size.

Some minor comments:

1. Line 17: To enhance clarity, you can split the sentence into two as follows: "To constrain the total and other aerosol contents, we conducted an optical closure study. Subsequently, the optical properties and concentrations were estimated."

2. Line 46, “Currently, materials such as humic-like substances, polycyclic aromatic hydrocarbons, and lignin are all considered BrC” should be “Currently, materials such as humic-like substances, polycyclic aromatic hydrocarbons, and lignin are all considered as BrC”.

3. Line 106, “LT” should be “local time”.

4. The label (a) and (b) in figure 5 is missed.

5. Line 337, “that of BC” should be “that caused by BC”.

See attached review.