|I appreciate that the authors made a great effort to improve the manuscript significantly, especially running the model for a longer period of time to obtain a robust result. Many comments are addressed appropriately. However, it was able to find out some minor issues remaining. Plus, although many typos are corrected as the authors declared, still some (or the same) typos can be found again. Nevertheless, I believe that these can be addressed easily.|
P7L7-L18: This paragraph explains the sampling method used in the paper nicely. However, I am still curious about the sentence “MPAS simulated CO2 fields are interpolated in time and space to match each 5-second airborne data points” at P15L4-5. Because it looks inconsistent with the method explained here (interpolation in space vs. selecting nearest grid point overland). For ACT campaign data, is the sampling method used in section from 3.4.1 to 3.4.3 the same as the method used for sampling near-surface CO2 observations (section 3.3.3)? If they are the same, it needs to revise the sentence. If they are different, then please clarify why they are different.
P8L3: the sentence “CO2 mixing ratio is kept unchanged during the meteorology re-initializations” is in contradiction with the CO2 mass conservation method in section 3.2.2. Please clarify it.
P12L2-3: It is hard to understand what is “evident”. Please rephrase the sentence.
P12L5-7: Maybe it is better to remind it for readers that both model used the same CO2 fluxes so the difference is only caused by the different model transport.
P13L1: Is it possible to add 60 km uniform grid result over 15 km cell area (data in Table 3) in the table 6, in order to support the benefit of high-resolution? If you don’t have the result for CO2, it is fine with leaving it as is because I don’t ask an additional experiment.
P14L31-P15L1: This paragraph looks redundant. Please consider to move it to earlier part (section 3.1 or other proper place).
P15L6: Which version of ObsPack dataset did you use? Please specify it.
P17L15: Since paired t test is also used in Table 5. The explanation can be moved earlier part of the paper (section 3.3.3), if the same method is used.
P18L30: In summary section, please consider to mention briefly about an additional experiment using 60 km uniform-resolution presented in section 3.3.1.
P44: Table 2. What does “IGRA” stand for? Since it is not mentioned/explained in the main text. It would be better to add its full name or remove it.
P1L2: CTM -> CTMs
P2L1: CTM -> CTMs
P2L35: model(FV2) -> model (FVS) (add space)
P4L9: If the variable V here is the same one in eq. 1, then you can move this explanation to just after eq. 1.
P4L22L: YSU -> YSU scheme
P5L8: YSU ->scheme
P6L1: KF ->scheme
P6L17: It is difficult to understand what “simulation experiments” is. Please revise it.
P6L22: ACT -> ACT campaign
P8L7: “The four CT2019 fluxes” -> “The four components of CT2019 fluxes”
P8L29: Their model name is actually GEM-MACH-GHG, please check their paper.
P9L12: “the model’s initial and current time step global CO2 mass” -> “the global CO2 mass at the initial and current time step.”
P9L27: “To restore the CO2 mass conservation” -> “To keep the total CO2 mass”
P9L27: MPA-A’s -> MPAS-A’s
P10L19: CO22 (remove redundant 2)
P10L19: XCO2 (2 for subscript)
P12L6: GEM -> GEM-MACH-GHG
P12L30: “( 11.77” -> “(11.77” (remove space)
P12L31: “a accuracy level” -> “a level of accuracy” or other else
P14L25: project -> campaign
P14L29: analysis -> reanalysis
P14L31: CarbonTracker -> CT2019
P14L33: free troposphere -> FT
P15L6: CarbonTrack -> CT2019
P15L6: CarbonTrack ObsPack -> CarbonTracker ObsPack (or CT2019 ObsPack, depending on the version of dataset you used)
P15L14: free troposphere (FT) -> FT
P15L30: boundary layer -> BL
P15L30: free troposphere -> FT
P16L6: boundary layer -> BL
P16L30: boundary layer -> BL
P16L30: free troposphere -> FT
P19L28: CarbonTracker -> CT2019
P19L31: Maybe TCCON dataset information is necessary
P20L14: Maybe proper acknowledgment for TCCON dataset is necessary, depending on their data policy
P30: Figure 2. 1) Please make red solid lines in both panels have the same thickness. It would be good for better visualization. 2) “number of hours” looks wrong. Please correct it.
P31: Figure 3. 1) Please make the red solid lines in both panels have the same thickness. It could be good for better visualization. 2) “number of days” looks wrong. Please correct it.
P32: Figure 4. XCO2 -> simulated XCO2
P34: Figure 6. Please add period at the end of the caption.
P35: Figure 7. 1) “MPAS-A simulated hourly XCO2” -> “Simulated hourly XCO2 of MPAS-A”. 2) please add period at the end of the caption.
P40: Figure12. level-leg flight -> “constant altitude flight segments”
P42: Figure14. “for create” -> “for creating”
P43: Table 1. Please revise the caption.
P44: Table 2. add bracket for the unit (degree) in the 4th column.
P45: Table 3. 1) speed(m/s) -> speed (m/s) (add space), 2) add bracket for the unit (degree) in the 4th column
P50: Table 7. Please revise the caption
P51: Table 8. RMS -> RMSE
P53: Table 10. 1) MPAS -> MPAS-A, 2) “MPAS simulated horizontal wind” “simulated horizontal wind of MPAS-A”, 3) Add a comma after “1000”, 4) speed(m/s) speed (m/s) (add space), 5) add a bracket for the unit (degree) in the 4th column
P54: Table 11. “2017 winter” -> “Winter 2017”
P55: Table 12. Please revise the first sentence of the caption.