Added Value of Aerosol Observations of a Future AOS High Spectral Resolution Lidar with Respect to Classic Backscatter Spaceborne Lidar Measurements

Round 1

Reviewer 1 Report

General comments

This paper describes the advantage of the high-spectral-resolution lidar (HSRL) method over the conventional backscattering lidar for space-borne observations. Using a lidar simulator and a chemical transport model, the errors in the backscattering coefficient profiles derived from the backscattering lidar and HSRL are compared for three cases of aerosol events (desert dust, wild fire, and urban pollution). It is clearly demonstrated that the error in the backscattering coefficient is much smaller in HSRL than classical backscattering lidar where the forward inversion method is required with the lidar ratio assumption, especially in dense aerosol cases. The manuscript is suitable for the journal, and it is generally well written. It is recommended for publication after minor revisions.

 

Specific comments

There are several typos in the manuscript.

 

Line 134 and all following pages:

It is not appropriate to call the inversion method “Klett inversion method”, in my opinion. It was Fernald et al. who introduced the two-component (i.e. aerosol and molecule) forward inversion of the lidar equation. The equation essentially the same as Eq(7) in this paper appears in the paper by Fernald et al. in 1972 (Ref(12) in this paper). Moreover, the Fernald’s paper was published 9 years earlier than the Klett’s paper. The Klett method is a single component method, and backward inversion is essential in the Klett’s paper (Ref(11)). The inversion method used in this paper should be referred to as “Fernald inversion method” instead of “Klett inversion method”.

 

Section 2:

It would be much better if the simulated AOS AMB and APB, and HSRL BSC are shown for the same period as in Figure 4, to understand the SNR in the signals and the error in the backscatter coefficient in AOS HSRL.

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Lidar simulations are provided at 532 nm for elastic backscatter and HSRL lidars, emphasizing the superior retrievals for HSRL.

The following few suggestions/questions and spelling remarks are given below:

pp3, line 96: of instead of f

section 2.2.2.: is the process of NR validation in terms of AOD an ill-posed problem (i.e., can we have more than one combinations of various aerosol compositions which can prvide the same AOD)? Please comment on this aspect.

pp7, line 223: "On the other hand" instead of "in the other hand"

pp7, line 224: I think that "other" should not he there

pp8. line 241: "does not" instead of "do not"

pp8, line 245: "the aim" instead of "the aims"?

pp8, line 261: please replace qq citations

pp 10, line 309: Lidar equation (capital letter)

pp 10, lines 312-313: replace ?? with eq. number (11 and 12)

pp 11, line 339: when citing Weitkamp, please mention the chapter, as the book contains several chapters with various lidar equations.

pp 11, line354: sentence not clear; you may cut "at a"; or maybe you wanted to mention the resolution?

pp 11, line 360: replace "coughly" with "roughly"

pp 11. line 362: "the total power" instead of "the ottal poxer"

section 2.3.4.: you mention that the reference at 10km may include some aerosol; did you try using a reference at higher altitudes (e.g., 15 km) in order to avoid the potential aerosol contamination? on the other hand, the Caliop measurements do not show aerosol at 10km. How do you explain the presence of the aerosol in your simulations?

pp 15, line437: case studies instead of study cases?

pp 15, line 481: you mention 10 to 15 % differences for HSRL; however, looking at figure 6g, one can see ~0% (white region).

pp 17, line 488: showing instead of shown

pp 17, line 507: replace ?? with eq. number

pp 19, lines 541 and 545: I think it is 10^(-7)

pp 21, lines 588: fire18? Or maybe a biomass burning instead of biomass fire?

 

 

 

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

General comment:

In this work, added values from new satellite observations are analyzed to characterize the vertical distribution of the aerosol. Synthetic observations are simulated using the BLISS lidar simulator in terms of the backscatter coefficient at 532 nm. Two types of lidar instruments are considered, an elastic backscatter lidar instrument and a high spectral resolution lidar (HSRL). These simulations are performed on atmospheric profiles from a Nature Run (NR) modeled by the MOCAGE Chemical Transport Model. Three case studies involving large events of different aerosol species are proposed and the added value of the HSRL channel for measuring aerosol backscatter profiles compared to simple backscatter measurements is shown. It is believed that the work is interesting from a scientific point of view, therefore it can be published in this journal.

Minor commento:

1) Line 190 add ref

2) Table 2: - Telscope diameter 1 add:  [m]   

Replace the text in figure 5,7,8 : " Same as figure of..."  with right legend...is more  readble for the reader... instead of going up and down in the text!!

Author Response

Please see the attachment.

Author Response File: Author Response.pdf