Effects of Direct Assimilation of FY-4A AGRI Water Vapor Channels on the Meiyu Heavy-Rainfall Quantitative Precipitation Forecasts
Round 1
Reviewer 1 Report
see attachment
Comments for author File: 
Comments.pdf
Author Response
See attachment. Thank you!
Author Response File: Author Response.pdf
Reviewer 2 Report
General comments:
The study compares the assimilation result for AMSU-A alone with a two-stage assimilation, first with AMSU-A and then with AGRI.
It is left unclear, why the additional use of AGRI is expected to improve the model, please give here a motivation.
Although the paper fucusses on the achievable improvement due to AGRI use, there should also be a coarse description of the instrument data key parameters (temporal and spatial sampling, radiometric accuracies) and a reference containing more details for the interested reader.
The reader should not need to Google the relevant information, but it should be found in the paper.
Especially the different orbits (SSO for AMSU-A, geostationary for AGRI) may have a signifiant impact on the temporal sampling and the possible update frequency for the model.
Further the spatial sampling and the radiometric accuracies of the instruments play a crucial role in the accuracies of the assimilation result. This should be worked out more clearly.
The assimilation is done for the relatively short period of 72h, which is ok for a first proove of concept, but not sufficient for a statistical assessment of the capabilities. This should be made more clear.
Further, figures 12 and 13 are only for two selected time slots (and Figure 15 for a third one also). Here you could give the justification, why these particular slots have been chosen. Is the Meiyu rain only happening in the evening hours? Then please provide this information.
The thinning process is not well described. I understand that the satellite date are regridded with a mesh size of 60km / 120km. This would lead to only few meshes in the area of 700km x 540km, therefore I assume that I did not understand the process.
Detailed comments:
line 119: you write, 'some channels failed'. What exactly happens. Which channels are left in the assimilation? Usually, in an assimilation, you can not chose the data you like, but need to establish justified quality-flags.
line 103: please give references for WRF and NCEP.
Section 2, please provide an overview table with the different experiments you conducted, so one can easily see the differences.
line 178: please explain bias-corrected observation-background, as this is not obviouse for the reader.
Figure 5 (and Figure16): explain why there is a structure (i.e. the CSI changes with time). Is this due to the satellite data frequency, the diurnal variations of the atmospheric parameters, or something else?
Figure 6: in the text you explain that you parametrize the scan-angle with a fourth order polynomial and perform a dedicated bias correction. Nevertheless, in CH9 the shape of the bias does not change at all, and the slope in Ch10 (the box) only slightly decreases. This unexpected result needs to be discussed in more depth.
line 309: 'higher', I assume you mean higher in altutide and not in value. Please add altitude.
line 422: 'more water', as this is the discussin section, you could discuss whether more is better or worse.
Editorial
In some figures, the curves can not be distinguished in black-white print. E.g. figure 16, where the same symbols are used and the colours appear in the same greytone. It is recomendet to use different marker symbols, and it would be appreciated when also the colours are adapted.
please insert spaces when '-' is used as a subtraction operator (e.g. a - b), so it can be distinguished from a hyphen (e.g. black-white).
Throughout the paper, Figure captions are either cut (e.g. Figure4) or appear on the next page (e.g. Figure 11)
line 44-46: this is a doublication -> remove
line 115-117: this is not a sentence -> improve
Table 1: change Noah to NOAA
Figure 10: note in the capture what the grey bars indicate.
Figure 11: improve the x-axis capture. I assume it should be 'temperature (°C)'.
Author Response
See attachment. Thank you!
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Thank the authors for their diligent works and the modified revision has addressed most of my original concerns. As I mentioned in the first review, it should be published.
