Airborne measurements from the Southern California Investigation of Low cloud and Land Aerosol (SCILLA)

Witte, Mikael; Bahreini, Roya; Bollinger, Sierra; Bucholtz, Anthony; Chuang, Patrick; Collins, Don; Han, Minghao; Leandro, Mason; MacDonald, Alexander; Metcalf, Andrew; Ries, Bradley; Sunil, Nimya; Wang, Dongli; Welp, Lisa

doi:10.5194/essd-2026-593

Preprints

https://doi.org/10.5194/essd-2026-593

Preprints

04 Sep 2026

| 04 Sep 2026

Status: this preprint is currently under review for the journal ESSD.

Airborne measurements from the Southern California Investigation of Low cloud and Land Aerosol (SCILLA)

Mikael Witte, Roya Bahreini, Sierra Bollinger, Anthony Bucholtz, Patrick Chuang, Don Collins, Minghao Han, Mason Leandro, Alexander MacDonald, Andrew Metcalf, Bradley Ries, Nimya Sunil, Dongli Wang, and Lisa Welp

Abstract. The Southern California Investigation of Low cloud and Land Aerosol (SCILLA) was an airborne field experiment flown in June 2023 based out of San Diego, California. The objectives of the experiment were to investigate dynamical controls on aerosol transport from land over the ocean, quantify the impacts of aerosol-cloud interactions on planetary boundary layer (PBL) evolution, and characterize gradients in atmospheric properties across the PBL-topping inversion to constrain transport hypotheses. A total of 20 research flights were flown over the Southern California Bight, with 18 flights in the vicinity of San Clemente Island and an additional 2 flights over the Los Angeles basin and offshore of the adjacent coastline near Santa Monica and Malibu. A twin turboprop aircraft was outfitted with a broad array of instruments to sample basic meteorology (thermodynamics and winds); aerosol physical, chemical and radiative properties; cloud and drizzle microphysics; radiation; and trace gases. Detailed descriptions of flight sampling strategies, aircraft instrumentation and derived products are given and an overview of each research flight is provided as a reference for data users. The primary dataset, merged 1 and 10 Hz aircraft data, is globally available at https://doi.org/10.5281/zenodo.21826965.

Received: 25 Jul 2026 – Discussion started: 04 Sep 2026

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.

Download & links

Status: open (until 11 Nov 2026)

Post a comment Subscribe to comment alert

RC1:
'Comment on essd-2026-593', Jeff French, 13 Oct 2026 reply
This manuscript provides an overview of data that were collected during the Southern California investigations of Low cloud and Land Aerosol (SCILLA) experiment in June of 2023. The manuscript provides an excellent overview of the project and the data that were collected and now available through the project archives. It provides an appropriate level of detail for a data science paper and will serve as a good starting point and reference for future users of this data set. Therefore I recommend publication once the authors address my minor comments below.
Minor Comments -
The authors are slightly inconsistent when discussing the number of research flights. In some locations they refer to 20 research flights (abstract) or list out just the 20 principal flights (Table A1); but in others refer to 21 flights (line 30) and Table 1. They are clear that RF01 was a 'shakedown' flight and that there was little usable data (line 31)....for those purposes I would simply state on line 30 that there were 20 research flights labeled RF02 through RF21, keeping the sentence on line 30 & 31 re: RF01; removing RF01 from table 1; and changing the beginning of the sentence on line 32 to read: 'Most (18) of the 20 research flights sampled the ....'

Figure 2 -- Throughout the manuscript, the authors refer to various islands (San Clemente (SCI), Santa Catalina, and San Nicolas)....it would be helpful to the uninformed reader, myself among them, to label those islands in this figure.

Figure 3 -- It is hard to distinguish the different flights based on the color selection. I'm not sure if using significantly different colors would produce a figure that is equally hard to interpret, especially for the upwind/downwind contrast (c) because there are so many flights. However, in many cases the colors are so similar it is impossible to determine differences between flights.

Line 106-7 'True airspeed is derived from the aircraft vector velocity .... recorded by the INS' Is the a typo? Are you referring to the aircraft ground speed /// ground velocity? True airspeed does not come from an INS but rather from a Pitot/static pressure measurement (that provides indicated airspeed) and then corrected for density using atmospheric state (temperature and pressure) to calculate true airspeed).

If CMH was inoperable during RF05, then I assume this is what led to MET being not good for the entire flight (according to Table A1)? Since water vapor comes into all calculations of thermodynamics and wind? Or was one of the other water vapor measures used in place of CMH?

Line 242 -- the phrase: '....although the response function for drops of Diameter Dp>30 um has been show to drop off at smaller sizes (Wendisch et al, 2002).' This sentence suggests to me that the response decreases with decreasing size, but that is not correct...Wendisch et al. state that the response decreases with increasing drop size and their wind tunnel suggests response begins to decrease when MVD > 20 um (at smaller sizes than was believed from theoretical considerations).

Section 4.8 cloud microphysics -- The authors do an excellent job describing the PVM (above comment notwithstanding) and the PDI measurements. However, little information is provided about the CAPS data; particularly the CAS and the CIP part. A description of how these data are handled/processed and known problems would be helpful. Perhaps this is described in Sorooshian et al. (2018) [I did not look up the reference]; and if so, I think it would be appropriate to add a statement pointing the interested reader to that paper for details of data handling and processing. If not, then I think it would be good to describe what (if any corrections) are applied to the data, such as correcting for coincidence (in CAS), shattering (in CIP and CAS), and/or DOF (for smaller particles in CIP).

Section 6 -- Overview of flights. At the end of each flight overview, it would be useful to add a sentence or two regarding data quality from each flight. Flights with more data issues may require a few more sentences. I realize this information is in Table A1, however including it in the flight summaries is useful as individuals considering specific flights for their analysis would typically like to know up front if there are data issues with certain instruments.

Reply
Citation: https://doi.org/10.5194/essd-2026-593-RC1

Data sets

SCILLA merged 1 Hz and 10 Hz airborne data M. K. Witte et al. https://doi.org/10.5281/zenodo.21826965

Video supplement

SCILLA forward cockpit video M. K. Witte et al. https://youtu.be/DilmQmxxuUs?si=mRRHGmn7CD2RP0Mx

Viewed

Total article views: 436 (including HTML, PDF, and XML)

HTML	PDF	XML	Total	BibTeX	EndNote
267	103	66	436	87	78

HTML: 267
PDF: 103
XML: 66
Total: 436
BibTeX: 87
EndNote: 78

Views and downloads (calculated since 04 Sep 2026)

Month	HTML	PDF	XML	Total
Sep 2026	177	62	38	277
Oct 2026	90	41	28	159

Cumulative views and downloads (calculated since 04 Sep 2026)

Month	HTML	PDF	XML	Total
Sep 2026	177	62	38	277
Oct 2026	90	41	28	159

Viewed (geographical distribution)

Total article views: 436 (including HTML, PDF, and XML) Thereof 436 with geography defined and 0 with unknown origin.

Country	#	Views	%

Latest update: 18 Oct 2026

Short summary

The Southern California Investigation of Low cloud and Land Aerosol (SCILLA) was an airborne experiment in June 2023. The goal was to understand how wind patterns and islands in the Southern California Bight affect airborne particulate matter and cloud drops. We flew a total of 20 flights. The aircraft had instruments to sample clouds, particulate matter, meteorology, and atmospheric gases. The paper describes how we flew, lists the instruments flown, and gives a summary of each flight.


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