the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 06 Nov 2024
Measurement Report: Vertically resolved Atmospheric Properties Observed over the Southern Great Plains with Uncrewed Aerial System – ArcticShark
Abstract. This study presents the unique capability of the DOE ArcticShark – a mid-size Uncrewed Aerial System (UAS) – for measuring vertically resolved atmospheric properties over the Southern Great Plains (SGP) of the United States. Focusing on atmospheric states and aerosol properties, we overview measurements from 32 research flights (~ 97 flight hours) carried out in 2023. Our data from March, June, and August 2023 reveal distinctive seasonal patterns within the atmospheric column through unique chemical composition measurements. These two measurement techniques— in situ and remote sensing— provide valuable insights into their consistency and complementarity. The August operations, aided by a visual observer on a chase plane, allowed for extensive UAS coverage, surpassing typical UAS operation envelopes. Furthermore, we demonstrate the capabilities of the ArcticShark through several case studies, including the analyses of correlations between UAS-derived atmospheric profiles and conventional radiosonde measurements, as well as the derivation of vertically resolved profiles of aerosol chemical, optical, and microphysical properties. These case studies highlight the versatility of the ArcticShark UAS as a powerful tool for comprehensive atmospheric research, effectively bridging data gaps and enhancing our understanding of vertical atmospheric structures in the region.
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Status: final response (author comments only)
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RC1: 'Comment on egusphere-2024-3089', Anonymous Referee #1, 09 Dec 2024
The paper summarizes measurements made onboard the Arctic Shark above the SGP ARM site over a period of 3 years. The paper achieves its stated goal of demonstrating the use of the UAS for observations of meteorological and aerosol properties. The following comments should be addressed before publication.
Table 1: It would be helpful to add the actual instrument and manufacturer information to the table.
Measured particle size ranges should be provided for all in situ particle measurements.
Lines 122 – 123: What exactly is the ArcticShark chemical filter collecter? What filters are used? What is the size range?
Lines 156 – 158: How does the assumption of a uniform aerosol composition affect the removal of the influence of humidification from the extinction profiles and retrieval of the vertical CCN concentrations? The assumption is expected to have an impact on the accuracy of the retrievals for dust versus sulfate, for example.
Figure 2d: please provide the particle size range measured by the POPS.
Line 202: Please provide more details about the “haze environment” in August. Is this due to agricultural burning?
Line 207: Please provide the size range of the accumulation mode that is referred to here.
Line 208: With the chemical composition information couldn’t more said here about the importance of secondary particle formations and emissions from agricultural sources?
Figure 3 a and b: Any explanation for the offset between the AIMMS-30 and LICOR aboard the UAS?
Figure 3 c and d: Coefficients of determination show good agreement between the UAS and balloon wind direction and speed but there is a lot of spread in the data. Any explanation? How far apart were the two platforms?
Figure 4: How is the PBL height determined?
Lines 250 – 252 are redundant with lines 224 – 226.
There is a lot of repeated text between pages 11 and 12.
Line 264: Fight days in March? Should be flight days.
Table 2: are 4 to 5 significant figures warranted for reported O/C and H/C ratios?
Citation: https://doi.org/10.5194/egusphere-2024-3089-RC1 -
RC2: 'Comment on egusphere-2024-3089', Anonymous Referee #2, 23 Dec 2024
The authors present a well-written overview of an extensive new dataset of measurements from aboard a UAS complemented by other in situ and remote sensing measurements. The measurements and conclusions drawn seem to be scientifically sound, and I can see how the dataset will be useful to other scientists. The paper is therefore certainly suitable for an ACP Measurement Report, when the following comments are addressed.
Comments are in order of the manuscript. Further small editorial comments can be found in the attached marked-up PDF.
Line 12: define the abbreviation DOE in the abstract
Line 16: You haven’t introduced the measurement techniques yet, although you refer to them here. You should provide a short overview of your measurements in the abstract, specifically what you measure with the UAS and what you compare them with (remote sensing and radiosondes).
Line 63: define UAS (first time you use it in the main text).
Line 81: “mid-size UAS” – please indicate how large the UAV is (e.g., wing span), and specify that it is fixed-wing.
Line 99: “to provide high-frequency measurements” – of what? Temp? RH? Wind? Pressure?
Table 1: Please add to this table what variables specifically are included for each data product. For example, what specifically is included in the AIMMS “meteorological data”? And all particle counters should have their size range included, and whether they report only number concentrations or also size distributions. Please also include the model and producer of each instrument. Finally, please also specify whether the data is collected on board the UAS or from another platform.
Section 2.2 chemical analyses: This section reads as what could be measured, but it is unclear what is actually measured in this study. Please specify what tests were done on these measurements provided here.
Section 2.3 VAPs: Please define each acronym you use. Cloud type (CLDTYPE), etc.
Section 3.1.1: Please provide a table that lists every flight with their date, time range, maximum altitude, and which measurements were taken. In the following figures where you show averages across each month, it is important to know how many flights were included in the average.
Line 167-168: Could you say more about the “chase plane”? Was this a crewed aircraft that followed the UAV? I don’t quite understand why this was needed or how it fits into the measurement plan. A main advantage of UAVs is that no crew is needed, but if a crewed aircraft is needed here to obtain high-altitude measurements, then what is the advantage of using a UAV? Additionally, does this mean that your UAV can only fly within line of sight? More information is needed.
Section 3.1.2: I would suggest breaking up this section into smaller sections for each data type / comparison, e.g., vertical profile monthly overview, comparison with radiosoundings, comparison with remote sensing, and back-trajectories
Line 181: Please indicate over how many flights the data was averaged. (See above comment about adding a table of flights.)
Line 187: Figure S1 does not show relative humidity measurements (nor does Fig S2 or S3). Please add in the RH measurements to those plots.
Line 187: You state that RH “showed more variation in March”, but that is quite difficult to see in Figure 2. Could you provide numbers to support this statement? Or remove the statement.
Line 190: “ArcticShark can fly through holes in broken cloud fields” – does this mean that your UAV cannot fly in clouds? (Is that because it cannot fly out of line of sight?) I think it is an important drawback to mention, because clouds are an important part of atmospheric measurements. It may also be good to mention whether your UAV can fly in icing conditions.
Figure 2: Please specify in the caption what the particle size ranges are for the CPC and POPS. Also write in the caption what the points represent (averages over X number of flights, with standard deviation (?) error bars)
Line 198-200: You assert that “the total number concentrations of ambient particles” remain “stable” and “do not vary significantly” over the three months. I would be more careful with the wording. Specifically, you are referring to the CPC particle concentrations, not the POPS (which would also be called total particle number concentrations, just over a different size range). Furthermore, it is only the means which do not vary significantly, because there is still quite a bit of variation around each mean. That indicates that there isn’t much difference between the three months, but there is variation within each month.
Line 211 – 226: Here you describe weather balloon data. Earlier in the manuscript you use the term radiosonde. I would suggest sticking with radiosonde everywhere. It would also be good to specify the specific instrument types (model, producer) of the radiosondes.
Line 222-223: You only briefly mention the wind direction and speed comparison. Could you add more about why there is not such good agreement? The agreement is not so bad, but it is certainly much worse than temperature and RH, and I think this should be acknowledged, with some reasoning as to why this might be.
Line 236: Where do the PBL measurements come from? Ceilometer measurements?
Figure 4: the titles “cloud masks” are not needed. Please also indicate in the caption where the cloud mask and PBL measurements were derived from (which instruments).
Line 248 – 263: Please remove this repetition.
Line 277 – 281: This should be a new paragraph, and, can you say more about the aerosol layer that the UAV flew through? Did you also get interesting aerosol measurements there? I think that showing aerosol particle number concentration timeseries in Figure 5 would support the comparison to the remote sensing measurements.
Figure 5: The colors/lines are tough to read here. Please increase resolution and consider altering the colors and line thicknesses. Additionally, the TKE line is red while the TKE right y-axis is yellow - please keep it consistent. Also, the UAS altitude is, I guess, shown as the black line, but the figure legend reads “MSL” for that line, so please rename it.
Figure 6: It could help here to add titles to each subplot indicating the date, time, and whether it was higher altitude or ground level. Please also give a more useful name for the colorbar and explain it in the caption.
Section 3.2.1: I don’t see how this is a case study, because you have many samples presented here. Furthermore, it is unclear whether these chemical analyses were done for all flights or whether this is just a subset of flights (again, see above comment about a table listing all flights). Please also give more information about what type of filter sampling was done.
Figure 8: Add AGL to the y-axis. Alternatively, it would be good to convert it to MSL to be consistent with previous figures.
Figure 9: What does the title “Sc = 0.185” mean? Please add it to the caption or remove if not important.
Section 3.2.3: Please say more about the CCNc VAP data product. Where does it come from / what is it based on? Do you measure surface CCNc?
Line 431-434: These conclusions were drawn from both ground-based remote sensing and UAV measurements. Please be careful about which conclusions come from which measurements, because it sounds here like this was all from UAV measurements.
Line 446: “diverse atmospheric conditions” – I think this is too strong of a statement, as you only have measurements from spring and summer, and not in clouds (as far as I understand). Please consider revising it.
Data sets
ARM dataset for ACP paper Fan Mei https://adc.arm.gov/essd/ACP_Mei
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