the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 21 Nov 2023
Enhancing Mobile Aerosol Monitoring with CE376 Dual-Wavelength Depolarization Lidar
Abstract. We present the capabilities of a compact dual-wavelength depolarization lidar to assess the spatio-temporal variations in aerosol properties aboard moving vectors. Our approach involves coupling the lightweight CIMEL CE376 lidar, which provides measurements at 532 nm and 808 nm and depolarization at 532 nm, with a photometer to monitor aerosol properties. The assessments, both algorithmic and instrumental, were conducted at ATOLL (ATmospheric Observatory of liLLe) platform operated by the Laboratoire d’Optique Atmosphérique (LOA), in Lille France. An early version of the CE376 lidar co-located with the CE318-T photometer and with a multi-wavelength Raman lidar were considered for comparisons and validation. We developed a modified Klett inversion method for simultaneous two-wavelength elastic lidar and photometer measurements. Using this setup, we characterized aerosols during two distinct events of Saharan dust and dust smoke aerosols transported over Lille in spring 2021 and summer 2022. For validation purposes, comparisons against the Raman lidar were performed, demonstrating good agreement in aerosols properties with relative differences of up to 12 % in the depolarization measurements. Moreover, a first dataset of CE376 lidar and photometer performing on-road measurements was obtained during the FIREX-AQ (Fire Influence on Regional to Global Environments and Air Quality) field campaign, deployed in summer 2019 over the Northwestern USA. By lidar and photometer mapping in 3D, we investigated the transport of released smoke from active fire spots at William Flats (North East WA, USA). Despite the extreme environmental conditions, our study enabled the investigation of aerosol optical properties near the fire source, distinguishing the influence of diffuse, convective, and residual smoke. Backscatter, extinction profiles, and column-integrated lidar ratios at 532 and 808 nm were retrieved for a quality-assured dataset. Additionally, Extinction Angstrom Exponent (EAE), Color Ratio (CR), Attenuated Color Ratio (ACR) and Particle Linear Depolarization Ratio (PLDR) were derived. In this study, we discuss the capabilities (and limitations) of the CE376 lidar in bridging observational gaps in aerosol monitoring, providing valuable insights for future research in this field.
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RC1: 'Comment on egusphere-2023-2579', Anonymous Referee #1, 26 Jan 2024
The micropulse lidars (MPL) are popular tools for the study of aerosol, due to their relatively low price, eye safety and capability for continuous operation. However, in these lidars only elastic backscatter is analyzed, which poses the complications for retrieval the aerosol backscattering and extinction coefficients. Thus, the novel approaches for the MPL data handling are welcome by the lidar community. The manuscript provides description of the new dual wavelength MPL Cimel CE376 as well as approach to data analysis, based on the use the AOD measured by the Sun Photometer. It is important, that authors performed MPL observations collocated with Mie-Raman lidar, allowing to validate their approach. The mobile lidar observations at the proximity of fires also demonstrate new interesting results. The manuscript is well written, contains new useful information and suitable for AMT.
Technical comments:
I would suggest to compare lidar ratios used in calculations with values provided by AERONET.
Ln 123. Would be good to have more information about 808 nm diode: linewidth, pulse duration, manufacturer.
Ln 135-139. The system uses grid polarizers, so no reason to discuss crosstalk between channels.
Ln 230-235. It was published many times, so probably no reason to repeat.
Section 3.1.3. I am a little confused. Authors introduce EAE for 532-808 nm. But for Klett method, extinction and backscattering profiles have the same shape (we can see it in Fig.5). Does CR bring new information comparing to EAE?
Ln 298. “we retrieve LR, extinction, backscattering at both wavelengths”. I would not call it retrieval, because were are 4 unknowns and 2 equations. It is more like estimation.
Fig.5f. Lidar ratio at 808 nm is higher than at 532 nm, which looks unusual for me. Did authors compare their results with lidar ratios provided by AERONET? LILAS LR above 4 km is probably untrustable.
Ln 406. VLDR provides not much information for comparison. So better focus at PLDR.
Citation: https://doi.org/10.5194/egusphere-2023-2579-RC1 - AC2: 'Reply on RC1', Maria Fernanda Sanchez Barrero, 13 Mar 2024
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RC2: 'Comment on egusphere-2023-2579', Anonymous Referee #2, 05 Feb 2024
This study aims to demonstrate the capabilities of a compact dual-wavelength depolarisation lidar in evaluating the spatiotemporal distribution of aerosol properties, especially when deployed on mobile platforms and collocated with a photometer. A modified Klett inversion method was employed. Firstly, some results were compared with a reliable Mie-Raman lidar under different aerosol scenarios, to evaluate both the method’s efficacy and the instrument’s suitability. Afterwards, the system was employed during the FIREX-AQ campaign in the summer 2019.
The manuscript is well-written and structured, and the insights are novel and valuable. It is appropriate for publication in AMT.
Minor Revisions
- Lines 37-38: I suggest adding also the reference Papagiannopoulos et al. (2020): An EARLINET early warning system for atmospheric aerosol aviation hazards, Atmos. Chem. Phys., 20, 10775–10789, https://doi.org/10.5194/acp-20-10775-2020, 2020.
- Line 40: I suggest adding also the reference Pappalardo et al., EARLINET: towards an advanced sustainable European aerosol lidar network, Atmos. Meas. Tech., 7, 2389-2409, doi:10.5194/amt-7-2389-2014, 2014.
- Lines 59-61: This statement is generally true. However, there are some exceptions. For instance, lidars from MPLNET and PollyXT (Engelmann et al., 2016; doi:10.5194/amt-9-1767-2016) are compact and easily transportable lidars, capable of operating 24/7 automatically. Please, qualify that statement.
- Line 121: could you specify what the acronyms ‘G, GP, GPN, N’ mean?
- Lines 148-151: the authors explained the different levels of data from the photometers used in this study. Please specify in the text which level of data (LV1.5 or LV2.0) has been employed.
- Lines 212-213: I suggest adding also the reference Córdoba-Jabonero et al. (2021): Experimental assessment of a micro-pulse lidar system in comparison with reference lidar measurements for aerosol optical properties retrieval, Atmos. Meas. Tech, 14, 5225-5239, doi:10.5194/amt-14-5225-2021.
- Line 370 (section 4.2.1): the authors investigate a case of dust over Lille. Indeed, the optical properties are characteristics of this type of aerosol. However, any ancillary analysis supports the assertion that it is Saharan dust. For instance, it should be interesting to include an analysis that confirms the source of the dust. For instance, back trajectories analysis from HYSPLIT model (https://www.ready.noaa.gov/hypub-bin/trajtype.pl)
Technical Revisions
- Line 72: The acronym LILAS is not defined until line 346. Please, correct it.
- Line 165: Please, specify what ‘MAP-IO’ stands for.
- Line 194: Please, correct the format of the reference Kovalev and William (2004).
- Lines 319-320: Please, order the references by year.
- Line 401: The text refers to Fig. 5f, not to Fig. 4f.
Citation: https://doi.org/10.5194/egusphere-2023-2579-RC2 - AC1: 'Reply on RC2', Maria Fernanda Sanchez Barrero, 13 Mar 2024
Status: closed
-
RC1: 'Comment on egusphere-2023-2579', Anonymous Referee #1, 26 Jan 2024
The micropulse lidars (MPL) are popular tools for the study of aerosol, due to their relatively low price, eye safety and capability for continuous operation. However, in these lidars only elastic backscatter is analyzed, which poses the complications for retrieval the aerosol backscattering and extinction coefficients. Thus, the novel approaches for the MPL data handling are welcome by the lidar community. The manuscript provides description of the new dual wavelength MPL Cimel CE376 as well as approach to data analysis, based on the use the AOD measured by the Sun Photometer. It is important, that authors performed MPL observations collocated with Mie-Raman lidar, allowing to validate their approach. The mobile lidar observations at the proximity of fires also demonstrate new interesting results. The manuscript is well written, contains new useful information and suitable for AMT.
Technical comments:
I would suggest to compare lidar ratios used in calculations with values provided by AERONET.
Ln 123. Would be good to have more information about 808 nm diode: linewidth, pulse duration, manufacturer.
Ln 135-139. The system uses grid polarizers, so no reason to discuss crosstalk between channels.
Ln 230-235. It was published many times, so probably no reason to repeat.
Section 3.1.3. I am a little confused. Authors introduce EAE for 532-808 nm. But for Klett method, extinction and backscattering profiles have the same shape (we can see it in Fig.5). Does CR bring new information comparing to EAE?
Ln 298. “we retrieve LR, extinction, backscattering at both wavelengths”. I would not call it retrieval, because were are 4 unknowns and 2 equations. It is more like estimation.
Fig.5f. Lidar ratio at 808 nm is higher than at 532 nm, which looks unusual for me. Did authors compare their results with lidar ratios provided by AERONET? LILAS LR above 4 km is probably untrustable.
Ln 406. VLDR provides not much information for comparison. So better focus at PLDR.
Citation: https://doi.org/10.5194/egusphere-2023-2579-RC1 - AC2: 'Reply on RC1', Maria Fernanda Sanchez Barrero, 13 Mar 2024
-
RC2: 'Comment on egusphere-2023-2579', Anonymous Referee #2, 05 Feb 2024
This study aims to demonstrate the capabilities of a compact dual-wavelength depolarisation lidar in evaluating the spatiotemporal distribution of aerosol properties, especially when deployed on mobile platforms and collocated with a photometer. A modified Klett inversion method was employed. Firstly, some results were compared with a reliable Mie-Raman lidar under different aerosol scenarios, to evaluate both the method’s efficacy and the instrument’s suitability. Afterwards, the system was employed during the FIREX-AQ campaign in the summer 2019.
The manuscript is well-written and structured, and the insights are novel and valuable. It is appropriate for publication in AMT.
Minor Revisions
- Lines 37-38: I suggest adding also the reference Papagiannopoulos et al. (2020): An EARLINET early warning system for atmospheric aerosol aviation hazards, Atmos. Chem. Phys., 20, 10775–10789, https://doi.org/10.5194/acp-20-10775-2020, 2020.
- Line 40: I suggest adding also the reference Pappalardo et al., EARLINET: towards an advanced sustainable European aerosol lidar network, Atmos. Meas. Tech., 7, 2389-2409, doi:10.5194/amt-7-2389-2014, 2014.
- Lines 59-61: This statement is generally true. However, there are some exceptions. For instance, lidars from MPLNET and PollyXT (Engelmann et al., 2016; doi:10.5194/amt-9-1767-2016) are compact and easily transportable lidars, capable of operating 24/7 automatically. Please, qualify that statement.
- Line 121: could you specify what the acronyms ‘G, GP, GPN, N’ mean?
- Lines 148-151: the authors explained the different levels of data from the photometers used in this study. Please specify in the text which level of data (LV1.5 or LV2.0) has been employed.
- Lines 212-213: I suggest adding also the reference Córdoba-Jabonero et al. (2021): Experimental assessment of a micro-pulse lidar system in comparison with reference lidar measurements for aerosol optical properties retrieval, Atmos. Meas. Tech, 14, 5225-5239, doi:10.5194/amt-14-5225-2021.
- Line 370 (section 4.2.1): the authors investigate a case of dust over Lille. Indeed, the optical properties are characteristics of this type of aerosol. However, any ancillary analysis supports the assertion that it is Saharan dust. For instance, it should be interesting to include an analysis that confirms the source of the dust. For instance, back trajectories analysis from HYSPLIT model (https://www.ready.noaa.gov/hypub-bin/trajtype.pl)
Technical Revisions
- Line 72: The acronym LILAS is not defined until line 346. Please, correct it.
- Line 165: Please, specify what ‘MAP-IO’ stands for.
- Line 194: Please, correct the format of the reference Kovalev and William (2004).
- Lines 319-320: Please, order the references by year.
- Line 401: The text refers to Fig. 5f, not to Fig. 4f.
Citation: https://doi.org/10.5194/egusphere-2023-2579-RC2 - AC1: 'Reply on RC2', Maria Fernanda Sanchez Barrero, 13 Mar 2024
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