The paper presents a nice overview of the radio-occultation mission aboard

the Sentinel-6A satellite and a comprehensive and detailed description of

the developments and improvements of the non-time critical processing of

bending angle data of that mission.  It is well readable and can serve as

a reference to those interested in the mission data.

The manuscript could nevertheless be slightly improved by addressing some

minor issues and needed clarifications as discussed below.  After these

corrections the paper should be acceptable for publication in AMT.

- "Availability rate of 99.9%": clarification

  Page 1, line 5 states: "This analysis confirms the satellite’s

  capability to exceed its target of 770 quality checked bending angle

  profiles per day, with an availability rate of 99.9%, ..."

  This number is repeated in line 70, and it appears that its meaning

  should be clarified.  Table 1 gives a list of data gaps, and in view of

  figure 3 it should be clear that this cannot mean that 99.9% of the days

  the mission requirement of 770 occ/day is reached.  If that number

  refers to conditions where the instrument is working nominally, the data

  downlink works, etc., it should be stated as such.

  The text also mentions "autonomous or commanded instrument reboots" but

  does not give a frequency estimate.

  In Line 220 a total data loss of around 1.5% is quoted.  Assuming a

  roughly constant number of measurements per time, I would like to

  understand how these numbers relate.

- Line 127: formulation

  "The Sentinel-6A RO instrument’s performance, is required to provide ..."

  I think the following reads better:

  "The Sentinel-6A RO instrument requirement is to provide ..."

- Line 168: clarification

  "For both datasets, bending angle profiles were thinned to 247 vertical

  levels"

  I assume that the bending angle profiles were thinned to the common set

  of 247 vertical levels as for near-real time disseminated BUFR products

  as used by NWP.

- Line 173: clarification

  "This forward-modeling process converts ECMWF data on temperature,

  humidity, pressure, and geopotential, provided at 137 vertical levels at

  the reference occultation position, to 247 bending angle levels."

  My understanding is that ECMWF provides temperature, humidity, *surface*

  pressure, and *surface* geopotential (orography).  The forward-modeling

  process (e.g. Abel integral) is not simply a conversion; it *derives*

  the model-equivalent of the bending angles at the selected 247 levels

  from the input variables.  Please try to find an adequated formulation.

- Line 185: "770 bending angle profile" - use plural: profiles

- Line 200: "Subsequent Sentinel-6A RO processor updates made it more

  robust to these kind of issues." - either "this kind" or "these kinds"

- Line 229: "or RO profiles" - "or" should read "of"

- Line 230: clarification

  "It's worth nothing that lower SNR missions like SPIRE have demonstrated

  the ability to systematically detect key atmospheric features."

  It is certainly a matter of taste what "key atmospheric features" are.

  If the authors mean (lower) tropospheric/atmospheric features, they

  might say so.

- Figure 6 and text after line 255: clarification needed

  Not being an expert, I fail to understand yaw flips decrease the SNR

  both for rising and for setting occultations even for *GPS* signals.

  Figure 5 top row suggests that SNR for GPS is roughly independent of

  PRN, so that a naive reader might guess that exchanging the antennae

  would decrease the SNR for setting but increase the SNR for rising.

  So forgetting GLONASS for the argment, why do we see what figure 6 top

  row shows?  I cannot understand it from the text in lines 255ff.

- Figure 8: I only see "bias" in the plot, so "standard deviation" should

  be removed from the x-axis label.

  Furthermore, in the caption: "are showed" should read "are shown".

  This should also be fixed in more places (fig.9,11,13,16,17,18,19,20).

- Line 369: "the JPL provide navigation bit data file" -> *provided*

- Line 408: "where other error contribution, in particular.." ->

  *contributions*.

- Figure 14, caption: "occultation recorder" -> *recorded*

- Line 460: "SRN" -> "SNR"

- Line 469: formulation

  "An alternative approach consisting on integrating the L2 cutoff ..."

  Maybe better:

  "An alternative approach of integrating the L2 cutoff ..."

- Line 477: "leading to have a tropospheric bias shift" - remove "have"?

- Line 490: "bending angles profiles" -> "bending angle profiles"

- References, line 563 (and citations in the text):

  Author "Ho, Shu-Peng" appears as "peng Ho".  Not sure if this is a

  problem with the bibliography style or the way the reference is handled.

  The actually used citation looks strange to me, and a fix should be

  attempted.

Review of:  “Assessment of Operational Non-Time Critical Sentinel-6A Michael

Freilich Radio Occultation Data: Insights into Tropospheric GNSS

Signal Cutoff Strategies and Processor Improvements” by Paolella et al 2024.

This is a nicely written manuscript about the updates done in the data processing algorithm chain for Sentinel-6A NTC product. For example, it includes a detailed analysis on daily number of occultations including quality of checked bending angles profiles of S6A. Loss of data was attributed to unstable number of GLONASS satellites, yaw flips or other instrument manoeuvres. Also, a good discussion about the importance of L2 cutoff point in this manuscript which potentially is important to other GNSS-RO data processing algorithms, too. Furthermore, the role of navigation was illustrated nicely with much detail.

I highly recommend its publication with some very minor edits listed below:

-page 5, l. 126: delete “then”

-page 5, l. 132: use “emphasize” instead of “underscores”

-page 7, In caption Table 1remove “)”

-page 8, l. 173: Which option in the forward operator is used? 1D or 2D?

-page 8, l. 177 and “which” after “phase, “

-page 8, l. 184 add “number” after “combined total”

-page 10 l.237: “PRN” Please write out acronym when used for the first time.

-page11, in caption of Figure 4: “SLTA” This is explained later on page 14 but maybe best to do it here, when used for the first time.

-page 11, l.258: “nothing” should be “noting”

-page 12, Fig.5: Add an x – axis, e.g “Various satellites”. Also, legend is difficult to read (too small).

-page 12, Fig.6: Please add more details in the caption what can be seen in the different panels. Especially for top right and bottom left it is difficult to see the difference between them (at least from the title).

-page 17, Fig.9: Define the different lines. Std dev in bold and bias are thin lines?

-page 18, l. 370: “these” should be “this”

-page 21, Fig.13. “bite” should be “bit”