the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 27 Dec 2025
CopterSonde-SWX: Development of a UAS-based Vertical Atmospheric Profiler for Severe Weather
Abstract. Growing demand for high spatiotemporal resolution observations in the planetary boundary layer (PBL) has driven the development of affordable, small uncrewed aircraft systems (UAS) technology to fill critical observational gaps and support improved understanding and future assimilation into prediction models. This work presents the CopterSonde-SWX (CSWX), an in-situ UAS vertical profiler that combines a high-thrust tilted-body airframe, a wind-vane flight mode for sampling undisturbed air, and a shielded actively ventilated sensor scoop to acquire thermodynamic and full 3D wind vectors without dedicated anemometers. Through a series of flow simulations and intercomparison field campaigns, including colocated flights with its predecessor (CS3D), Doppler wind lidars, and radiosondes, the CSWX demonstrated inter-sensor temperature uniformity within ± 0.2 °C across variable solar and wind regimes and achieved LESO-based wind retrieval RMSEs of 0.49 m s-1 (vertical) and 1.03 m s-1 (horizontal). In a nocturnal low-level jet case, the CSWX sustained winds up to ∼ 24 m s-1 at 520 m (versus the CS3D's 20 m s-1 limit at ∼ 275 m), with polynomial fits projecting a safe maximum wind tolerance of 29.5 m s-1 while retaining sufficient battery energy margin for safe return. These results support the CSWX as a resilient, high-fidelity platform for atmospheric profiling, advancing the transition from a research prototype to an operational instrument. Even though the CopterSonde is an experimental design, this work may serve as a guideline to define future standards for WxUAS development.
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Notice on discussion status
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
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Preprint
(15029 KB)
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(15029 KB) - Metadata XML
- BibTeX
- EndNote
- Final revised paper
Journal article(s) based on this preprint
Interactive discussion
Status: closed
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RC1: 'Comment on egusphere-2025-4843', Anonymous Referee #1, 22 Jan 2026
- AC1: 'Reply on RC1', Antonio Ricardo Segales Espinosa, 16 Mar 2026
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RC2: 'Comment on egusphere-2025-4843', Adam Houston, 16 Feb 2026
The authors do a great job of explaining the changes made to the Coptersonde. Experiments conducted are appropriate and described clearly. On balance, my comments fall somewhere between "technical corrections" and "minor revisions" Ultimately, getting this manuscript ready for final publication won't require much effort.
Line 57: Please include references to UAS data from TORUS and TORUS-LItE: https://doi.org/10.26023/FJD8-VMV2-XW0Y, https://doi.org/10.26023/E5PJ-5CN7-VQ0T, and/or citation to Houston et al. (2026).
Line 63: The authors refer to “conventional methods” as the reference for data quality and I assume this to mean radiosondes but if you have other examples in mind you should mention them here.
Line 70: Check formatting of this citation.
Line 73: The authors refer to the possibility of assimilating UAS data into NWP models. You should include citations to illustrate that this can (and has been) done.
Line 151: Expand GNSS.
Table 1: I know that energy expenditure in hover is a reference used for thrust calculations but hover time isn’t really a useful metric to provide here.
Table 1: The authors really need to specify the assumptions made to get to an estimate of 3000 m max altitude.
Line 163: As I note above, the authors need to be more specific what “theoretical maximum capabilities achievable under the right conditions” actually means. Some of this is based on analysis presented later which you should reference here, but all maximum values need to have assumptions clearly listed in the table caption and/or the text.
Line 281 and Figure 9b: A “green trend” is referenced but not included.
Line 310: I think the authors mean “non-NOAA-related”.
Line 324: The authors need to explain why the nocturnal inversion would cause sensor response to have “an influence on the results”.
Line 335: I’m not sure what “tighter alignment” means. Please explain.
Line 335: The authors are assuming that “smoother and more consistent temperature and relative humidity curves” equate to more accurate measurements. Can the authors defend this? Obviously, the sounding won't capture structures that lead to less smooth profiles but that doesn’t mean it’s correct. It’s just hard to know, without a high-fidelity reference, what's right.
Line 340: Lower RMSE will be heavily influenced by the variability in the profile, but, as noted above, this doesn’t mean it’s wrong.
Line 349: “RMSE for…vertical winds remained below 1 m/s”. RMSE for vertical wind <1 m/s isn't a valid benchmark. You should note that the RMSE for vertical wind is ~0.25 m/s.
Line 463: No where is it mentioned that the Coptersonde cannot consistently collect reliable observations on descent. This has to be stated somewhere. While a deeper dive into the reasons would be great to see, I don’t think it’s necessary for this manuscript.
Houston, A.L., C.C. Weiss, E.N. Rasmussen, M.C. Coniglio, C.L. Ziegler, B.M. Argrow, and E.W. Frew, 2026: Targeted Observation by Radars and UAS of Supercells: TORUS. Bulletin of the American Meteorological Society, Accepted. DOI: https://doi.org/10.1175/BAMS-D-23-0265.1.
Citation: https://doi.org/10.5194/egusphere-2025-4843-RC2 - AC2: 'Reply on RC2', Antonio Ricardo Segales Espinosa, 17 Mar 2026
Interactive discussion
Status: closed
-
RC1: 'Comment on egusphere-2025-4843', Anonymous Referee #1, 22 Jan 2026
- AC1: 'Reply on RC1', Antonio Ricardo Segales Espinosa, 16 Mar 2026
-
RC2: 'Comment on egusphere-2025-4843', Adam Houston, 16 Feb 2026
The authors do a great job of explaining the changes made to the Coptersonde. Experiments conducted are appropriate and described clearly. On balance, my comments fall somewhere between "technical corrections" and "minor revisions" Ultimately, getting this manuscript ready for final publication won't require much effort.
Line 57: Please include references to UAS data from TORUS and TORUS-LItE: https://doi.org/10.26023/FJD8-VMV2-XW0Y, https://doi.org/10.26023/E5PJ-5CN7-VQ0T, and/or citation to Houston et al. (2026).
Line 63: The authors refer to “conventional methods” as the reference for data quality and I assume this to mean radiosondes but if you have other examples in mind you should mention them here.
Line 70: Check formatting of this citation.
Line 73: The authors refer to the possibility of assimilating UAS data into NWP models. You should include citations to illustrate that this can (and has been) done.
Line 151: Expand GNSS.
Table 1: I know that energy expenditure in hover is a reference used for thrust calculations but hover time isn’t really a useful metric to provide here.
Table 1: The authors really need to specify the assumptions made to get to an estimate of 3000 m max altitude.
Line 163: As I note above, the authors need to be more specific what “theoretical maximum capabilities achievable under the right conditions” actually means. Some of this is based on analysis presented later which you should reference here, but all maximum values need to have assumptions clearly listed in the table caption and/or the text.
Line 281 and Figure 9b: A “green trend” is referenced but not included.
Line 310: I think the authors mean “non-NOAA-related”.
Line 324: The authors need to explain why the nocturnal inversion would cause sensor response to have “an influence on the results”.
Line 335: I’m not sure what “tighter alignment” means. Please explain.
Line 335: The authors are assuming that “smoother and more consistent temperature and relative humidity curves” equate to more accurate measurements. Can the authors defend this? Obviously, the sounding won't capture structures that lead to less smooth profiles but that doesn’t mean it’s correct. It’s just hard to know, without a high-fidelity reference, what's right.
Line 340: Lower RMSE will be heavily influenced by the variability in the profile, but, as noted above, this doesn’t mean it’s wrong.
Line 349: “RMSE for…vertical winds remained below 1 m/s”. RMSE for vertical wind <1 m/s isn't a valid benchmark. You should note that the RMSE for vertical wind is ~0.25 m/s.
Line 463: No where is it mentioned that the Coptersonde cannot consistently collect reliable observations on descent. This has to be stated somewhere. While a deeper dive into the reasons would be great to see, I don’t think it’s necessary for this manuscript.
Houston, A.L., C.C. Weiss, E.N. Rasmussen, M.C. Coniglio, C.L. Ziegler, B.M. Argrow, and E.W. Frew, 2026: Targeted Observation by Radars and UAS of Supercells: TORUS. Bulletin of the American Meteorological Society, Accepted. DOI: https://doi.org/10.1175/BAMS-D-23-0265.1.
Citation: https://doi.org/10.5194/egusphere-2025-4843-RC2 - AC2: 'Reply on RC2', Antonio Ricardo Segales Espinosa, 17 Mar 2026
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Tyler M. Bell
Abdullah A. Tasim
Aaron Quiroz
Jeremy D. Simms
Joshua Gebauer
Elizabeth N. Smith
The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.
- Preprint
(15029 KB) - Metadata XML
Please see attached referee report.