A New Dual-Frequency Stratospheric Tropospheric / Meteor Radar: System Description and First Results

Xu, Qingchen; Reid, Iain Murray; Cai, Bing; Adami, Christian; Zhang, Zengmao; Zhao, Mingliang; Li, Wen

doi:https://doi.org/10.5194/amt-2023-213

Preprints

https://doi.org/10.5194/amt-2023-213

Preprints

17 Nov 2023

| 17 Nov 2023

Status: a revised version of this preprint was accepted for the journal AMT and is expected to appear here in due course.

A New Dual-Frequency Stratospheric Tropospheric / Meteor Radar: System Description and First Results

Qingchen Xu, Iain Murray Reid, Bing Cai, Christian Adami, Zengmao Zhang, Mingliang Zhao, and Wen Li

Abstract. A new dual-frequency Stratospheric Tropospheric (ST) / Meteor radar has been built and installed at the Langfang Observatory in northern China. It utilizes a novel two-frequency system design that allows interleaved operation at 53.8 MHz for ST mode and at 35.0 MHz for Meteor mode, thus optimizing performance for both ST wind retrieval and meteor trail detection. In dedicated meteor mode, the daily meteor count rate reaches over 40,000 and allows wind estimation at finer time resolutions than the 1-hour typical of most meteor radars. The root mean square uncertainty of the ST wind measurements is better than 2 m/s when estimating the line of best fit with radiosonde winds. Preliminary observation results for one month of winter gravity wave (GW) momentum fluxes in the mesosphere, lower stratosphere and troposphere are also presented. A case of waves generated by the passage of a cold front is found.

Received: 11 Oct 2023 – Discussion started: 17 Nov 2023

Download & links

Qingchen Xu, Iain Murray Reid, Bing Cai, Christian Adami, Zengmao Zhang, Mingliang Zhao, and Wen Li

Status: closed

CC1:
'Comment on amt-2023-213', Vagner Castro, 11 Dec 2023

Dear Author,
What are the technical specifications of the STX2 solid-state transmitters, including parameters like efficiency, bandwidth, and operating temperature range?
Great work.
Thanks,
Vagner Castro

Citation: https://doi.org/10.5194/amt-2023-213-CC1
- AC1:
  'Reply on CC1', qingchen xu, 15 Dec 2023
  
  Thank you for your questions. The technical specifications of the STX2 solid-state transmitters are as follows:
  
  (1) Frequency: 30-60 MHz, factory set to a customer frequency, Bandwidth 10% of centre frequency
  
  (2) Power: 24kW peak scalable to 96kW, fixed at factory
  
  (3) Duty cycle: 10% max
  
  (4) Efficiency: 40% from AC mains to RF output
  
  (5) Temperature: 0-40 degrees Celsius
  
  Citation: https://doi.org/10.5194/amt-2023-213-AC1
  - CC2: 'Reply on AC1', Vagner Castro, 15 Dec 2023
    
    That's great. Thank you!
    Vagner
    
    Citation: https://doi.org/10.5194/amt-2023-213-CC2
RC1:
'Comment on amt-2023-213', Anonymous Referee #1, 16 Jan 2024

It is actually two radars, an ST radar and a meteor radar.

Citation: https://doi.org/10.5194/amt-2023-213-RC1
- CC3: 'Reply on RC1', Iain Reid, 17 Jan 2024
  
  Well, all of the hardware is identical except that there are two seperate antennas. This is not uncommon in radar systems, where array subsections, different configurations, and different antennas can be selected. Given current accepted nomenclature, we consider it to be one radar.
  
  Citation: https://doi.org/10.5194/amt-2023-213-CC3
- AC3: 'Reply on RC1', qingchen xu, 19 Feb 2024
  
  As Prof. Iain Reid, one of our co-authors has explained in CC3, we consider this new system as one radar.
  
  Citation: https://doi.org/10.5194/amt-2023-213-AC3
RC2:
'Comment on amt-2023-213', Anonymous Referee #3, 25 Jan 2024

Review comments:
A New Dual-Frequency Stratospheric Tropospheric / Meteor Radar: System Description and First Results
by
Qingchen Xu, Iain Murray Reid, Bing Cai, Christian Adami, Zengmao Zhang, Mingliang Zhao, Wen Li

General comment:
The manuscript presents the initial results of a recently installed ST/meteor radar at Langfang, China. The radar uses a dual-frequency transmitter and receiver system layout for interleaved operation in meteor and stratosphere-troposphere measurement mode. The system performance is demonstrated by wind observations. The stratospheric-tropospheric measurements are cross-compared to radiosondes. There are also results shown deriving gravity wave momentum fluxes. However, there are some concerns related to the analysis and conclusions of how this analysis. The manuscript fits well into the scope of the journal and will become publishable after addressing some concerns.

Comment:
Figures 16 and 17:
These Figures are a duplication of content and should be merged by including a second x-axis on top and a different line color.

Line 306-308:
The sentence seems to refer to Figure 15. However, this Figure shows the momentum fluxes as <u’w’> in m2/s2. Please change the sentence that is matches the units shown in Figure 15?

Section 4.2.2.
This section contains three lines and one equation. Figure 18, which the reviewer assumes, belongs to this section is not mentioned. The reviewer suggests removing this section entirely or expanding this part. This section appears to be disconnected from the main narrative of the paper. In its present form it cannot be published. However, the topic is scientifically important and might can be investigated in the future.

Lines 339-345:
This paragraph is very confusing. At first, different wavelet filters are described, but later Figure 19 and 20 show monthly mean and hourly mean winds? It is recommended to add information when the measurements were taken. The use of Figure 20 is unclear in the context of this paragraph. How do the mean winds compare to the other observations nearby e.g, Mohe, Wuhan?
The reviewer assumes that this section is supposed to path the way for the momentum flux analysis, it is recommended to show the original hourly time series with all waves included and the two filtered data products.

Sections 4.3.1 to 4.3.4:
GW momentum fluxes inferred from meteor radar observations are not straightforward. The most critical aspect is the vertical wind, which is severely biased. A simple least square fit might be not sufficient and more sophisticated mathematical approaches seem to be necessary (https://amt.copernicus.org/articles/15/5769/2022/amt-15-5769-2022.html). As described in the paper, some least square fits result in negative values of the Reynolds-stress tensor on the main diagonal. The momentum fluxes shown in Figure 21 reach values of up to 150 m/s. When applying equation (4), this would lead to mean flow accelerations in the order of 1000 m/s/day for the instantaneous observation. The reviewer suggests discussing these results with other measurements in the literature (e.g., https://doi.org/10.5194/angeo-33-1091-2015,https://doi.org/10.1002/2014GL060501, https://doi.org/10.1002/2016GL068599, https://doi.org/10.1002/2016GL072311). It would be also good to calculate the cooling rate that is associated with such a mean flow acceleration. The reviewer also suggests merging all four sections into one. Figure 22 is not needed.

Line 399-400:
Why not fill the gap region with radiometric temperature and wind observations, which are less sensitive to tropospheric clouds?

Conclusions/summary/outlook:
The conclusions should be revised. The new system is valuable, and the paper demonstrates very good science opportunities. These achievements should be emphasized in this section.

Minor comment:
Line 12: ‘novel’ – new is the better term as it is used in the title. Dual frequency operation with shared hardware is not entirely ‘novel’.
Line 37: ‘the’ is too much …regions with one radar.
Line 45: remove ‘directly by’
Line 46: cite Hocking, 2005 here
Figure 2: The figure Quality is low
Line 107: The ST-radar antenna array consists of linear polarized antennas?
Line 119: PRF of 200 kHz (700m monostatic range)???
Line 135: accumulated – may be collected.
Line 148-150: The spatial averaging of about 400 km in diameter removes many of the small-scale waves and thus limits the benefit of a 10- or 15-minute temporal resolution.
Figure 8 and 9 should be reduced. It is maybe sufficient to show one Figure with a few days (or a month) comparing both wind components.
Line 178-180: maybe reference: https://angeo.copernicus.org/articles/35/893/2017/
Line 223: Radar profiles from 30 minutes before …..
Line 264:265: Please add whether these velocities are the line-of-sight measurements of the vertical beam or fitted data from all five beams. Please also include in this section how the spectra are analyzed (moments method vs. fit?) and whether additional coherent or incoherent integrations are added. Also information of the dwell time can be summarized here.
Line 358-361: Maybe reference: https://angeo.copernicus.org/articles/39/1/2021/angeo-39-1-2021.html
Line 365: one 'window' too much

Citation: https://doi.org/10.5194/amt-2023-213-RC2
- AC2: 'Reply on RC2', qingchen xu, 19 Feb 2024
  
  Thanks for the very detailed comments and suggestions. We reply to these comments one by one in supplemental document.
  
  Citation: https://doi.org/10.5194/amt-2023-213-AC2

Status: closed

CC1:
'Comment on amt-2023-213', Vagner Castro, 11 Dec 2023

Dear Author,
What are the technical specifications of the STX2 solid-state transmitters, including parameters like efficiency, bandwidth, and operating temperature range?
Great work.
Thanks,
Vagner Castro

Citation: https://doi.org/10.5194/amt-2023-213-CC1
- AC1:
  'Reply on CC1', qingchen xu, 15 Dec 2023
  
  Thank you for your questions. The technical specifications of the STX2 solid-state transmitters are as follows:
  
  (1) Frequency: 30-60 MHz, factory set to a customer frequency, Bandwidth 10% of centre frequency
  
  (2) Power: 24kW peak scalable to 96kW, fixed at factory
  
  (3) Duty cycle: 10% max
  
  (4) Efficiency: 40% from AC mains to RF output
  
  (5) Temperature: 0-40 degrees Celsius
  
  Citation: https://doi.org/10.5194/amt-2023-213-AC1
  - CC2: 'Reply on AC1', Vagner Castro, 15 Dec 2023
    
    That's great. Thank you!
    Vagner
    
    Citation: https://doi.org/10.5194/amt-2023-213-CC2
RC1:
'Comment on amt-2023-213', Anonymous Referee #1, 16 Jan 2024

It is actually two radars, an ST radar and a meteor radar.

Citation: https://doi.org/10.5194/amt-2023-213-RC1
- CC3: 'Reply on RC1', Iain Reid, 17 Jan 2024
  
  Well, all of the hardware is identical except that there are two seperate antennas. This is not uncommon in radar systems, where array subsections, different configurations, and different antennas can be selected. Given current accepted nomenclature, we consider it to be one radar.
  
  Citation: https://doi.org/10.5194/amt-2023-213-CC3
- AC3: 'Reply on RC1', qingchen xu, 19 Feb 2024
  
  As Prof. Iain Reid, one of our co-authors has explained in CC3, we consider this new system as one radar.
  
  Citation: https://doi.org/10.5194/amt-2023-213-AC3
RC2:
'Comment on amt-2023-213', Anonymous Referee #3, 25 Jan 2024

Review comments:
A New Dual-Frequency Stratospheric Tropospheric / Meteor Radar: System Description and First Results
by
Qingchen Xu, Iain Murray Reid, Bing Cai, Christian Adami, Zengmao Zhang, Mingliang Zhao, Wen Li

General comment:
The manuscript presents the initial results of a recently installed ST/meteor radar at Langfang, China. The radar uses a dual-frequency transmitter and receiver system layout for interleaved operation in meteor and stratosphere-troposphere measurement mode. The system performance is demonstrated by wind observations. The stratospheric-tropospheric measurements are cross-compared to radiosondes. There are also results shown deriving gravity wave momentum fluxes. However, there are some concerns related to the analysis and conclusions of how this analysis. The manuscript fits well into the scope of the journal and will become publishable after addressing some concerns.

Comment:
Figures 16 and 17:
These Figures are a duplication of content and should be merged by including a second x-axis on top and a different line color.

Line 306-308:
The sentence seems to refer to Figure 15. However, this Figure shows the momentum fluxes as <u’w’> in m2/s2. Please change the sentence that is matches the units shown in Figure 15?

Section 4.2.2.
This section contains three lines and one equation. Figure 18, which the reviewer assumes, belongs to this section is not mentioned. The reviewer suggests removing this section entirely or expanding this part. This section appears to be disconnected from the main narrative of the paper. In its present form it cannot be published. However, the topic is scientifically important and might can be investigated in the future.

Lines 339-345:
This paragraph is very confusing. At first, different wavelet filters are described, but later Figure 19 and 20 show monthly mean and hourly mean winds? It is recommended to add information when the measurements were taken. The use of Figure 20 is unclear in the context of this paragraph. How do the mean winds compare to the other observations nearby e.g, Mohe, Wuhan?
The reviewer assumes that this section is supposed to path the way for the momentum flux analysis, it is recommended to show the original hourly time series with all waves included and the two filtered data products.

Sections 4.3.1 to 4.3.4:
GW momentum fluxes inferred from meteor radar observations are not straightforward. The most critical aspect is the vertical wind, which is severely biased. A simple least square fit might be not sufficient and more sophisticated mathematical approaches seem to be necessary (https://amt.copernicus.org/articles/15/5769/2022/amt-15-5769-2022.html). As described in the paper, some least square fits result in negative values of the Reynolds-stress tensor on the main diagonal. The momentum fluxes shown in Figure 21 reach values of up to 150 m/s. When applying equation (4), this would lead to mean flow accelerations in the order of 1000 m/s/day for the instantaneous observation. The reviewer suggests discussing these results with other measurements in the literature (e.g., https://doi.org/10.5194/angeo-33-1091-2015,https://doi.org/10.1002/2014GL060501, https://doi.org/10.1002/2016GL068599, https://doi.org/10.1002/2016GL072311). It would be also good to calculate the cooling rate that is associated with such a mean flow acceleration. The reviewer also suggests merging all four sections into one. Figure 22 is not needed.

Line 399-400:
Why not fill the gap region with radiometric temperature and wind observations, which are less sensitive to tropospheric clouds?

Conclusions/summary/outlook:
The conclusions should be revised. The new system is valuable, and the paper demonstrates very good science opportunities. These achievements should be emphasized in this section.

Minor comment:
Line 12: ‘novel’ – new is the better term as it is used in the title. Dual frequency operation with shared hardware is not entirely ‘novel’.
Line 37: ‘the’ is too much …regions with one radar.
Line 45: remove ‘directly by’
Line 46: cite Hocking, 2005 here
Figure 2: The figure Quality is low
Line 107: The ST-radar antenna array consists of linear polarized antennas?
Line 119: PRF of 200 kHz (700m monostatic range)???
Line 135: accumulated – may be collected.
Line 148-150: The spatial averaging of about 400 km in diameter removes many of the small-scale waves and thus limits the benefit of a 10- or 15-minute temporal resolution.
Figure 8 and 9 should be reduced. It is maybe sufficient to show one Figure with a few days (or a month) comparing both wind components.
Line 178-180: maybe reference: https://angeo.copernicus.org/articles/35/893/2017/
Line 223: Radar profiles from 30 minutes before …..
Line 264:265: Please add whether these velocities are the line-of-sight measurements of the vertical beam or fitted data from all five beams. Please also include in this section how the spectra are analyzed (moments method vs. fit?) and whether additional coherent or incoherent integrations are added. Also information of the dwell time can be summarized here.
Line 358-361: Maybe reference: https://angeo.copernicus.org/articles/39/1/2021/angeo-39-1-2021.html
Line 365: one 'window' too much

Citation: https://doi.org/10.5194/amt-2023-213-RC2
- AC2: 'Reply on RC2', qingchen xu, 19 Feb 2024
  
  Thanks for the very detailed comments and suggestions. We reply to these comments one by one in supplemental document.
  
  Citation: https://doi.org/10.5194/amt-2023-213-AC2

Qingchen Xu, Iain Murray Reid, Bing Cai, Christian Adami, Zengmao Zhang, Mingliang Zhao, and Wen Li

Viewed

Total article views: 357 (including HTML, PDF, and XML)

HTML	PDF	XML	Total	BibTeX	EndNote
236	90	31	357	15	16

HTML: 236
PDF: 90
XML: 31
Total: 357
BibTeX: 15
EndNote: 16

Views and downloads (calculated since 17 Nov 2023)

Month	HTML	PDF	XML	Total
Nov 2023	19	4	1	24
Dec 2023	55	18	10	83
Jan 2024	69	14	4	87
Feb 2024	41	18	8	67
Mar 2024	38	25	2	65
Apr 2024	14	11	6	31

Cumulative views and downloads (calculated since 17 Nov 2023)

Month	HTML	PDF	XML	Total
Nov 2023	19	4	1	24
Dec 2023	55	18	10	83
Jan 2024	69	14	4	87
Feb 2024	41	18	8	67
Mar 2024	38	25	2	65
Apr 2024	14	11	6	31

Viewed (geographical distribution)

Total article views: 350 (including HTML, PDF, and XML) Thereof 350 with geography defined and 0 with unknown origin.

Country	#	Views	%

Latest update: 15 Apr 2024

Short summary

To have better understanding for the dynamics of lower and middle atmosphere, we installed a newly designed dual-frequency radar system, using 53.8 MHz for near ground ~ 20 km wind measuring and 35.0 MHz for 70 ~ 100 km wind measuring. The initial results show its good performances, along with the analysis of typical winter gravity wave activities.


Total:	0
HTML:	0
PDF:	0
XML:	0