Breakout Summary Report


ARM/ASR User and PI Meeting

Scientific Findings from the First Year of SAIL and SPLASH Observations and Directions for the Coming Year
26 October 2022
2:00 PM - 4:00 PM
Daniel Feldman and Gijs de Boer

Breakout Description

This session will provide a brief overview of the Surface Atmosphere Integrated Field Laboratory (SAIL) Campaign and the Study of Precipitation, the Lower Atmosphere and Surface for Hydrometeorology (SPLASH) campaigns to advance the scientific understanding of atmospheric processes and land-atmosphere interaction processes that impact the water resources of the Colorado River. This session will summarize the first year of their operations, starting in the Fall of 2021, and cover the notable precipitation and aerosol events that occurred.

The goals of this session are (1) to familiarize the audience with notable events of Water Year 2022, (2) to illustrate the observational constraints that SAIL and SPLASH provide on the processes that dominate the mountainous hydrology of the Upper Colorado River and mid-latitude continental interior mountain ranges, (3) discuss scientific findings from the two campaigns to date, (4) introduce the new observations that are joining SAIL and SPLASH in the second year, including the NSF SOS project and the German Research Foundation’s CORSIPP project, (5) engage with the audience on their research questions and directions, and (6) build connections between the SAIL and SPLASH projects and other DOE-supported activities (e.g., model development efforts, Watershed SFA, etc.).

Main Discussion

The purpose of the breakout session was to provide an overview to the ARM/ASR PI meeting community of exciting developments with the SAIL campaign, including what has been found to date. The underlying reason for this focus was principally to pique interest from breakout session attendees so that they consider (1) taking a closer look at SAIL data, (2) initiating new scientific activities with SAIL and SPLASH data, and (3) pursuing collaborations with scientists involved in the SAIL and/or SPLASH campaigns.  Given that SAIL had been collecting data for more than 1 year when this breakout session was held (data collection started on September 1, 2021), this session was timely and the virtual format enabled attendance not just of the ARM/ASR PI meeting community, but also of researchers that continue to partner with SAIL or may form new partnerships.

The breakout session spanned two hours and had 10 science overview presentations followed by open discussion. First, the SAIL PI provided an in-person, high-level introduction to the SAIL campaign, its science objectives and its current status, including framing the science within the broader context of the recent draft Executive Summary published by Integrated Mountainous Hydroclimate (IMHC) workshop. 

Next, the SPLASH PI provided an in-person overview of the SPLASH campaign, its science objectives, what it is measuring, and its current status, including how it works synergistically with SAIL.

The third presentation focused on SAIL data. The SAIL data translator, Damao Zhang of the Pacific Northwest National Laboratory, delivered a virtual presentation on the status of SAIL data, noting which datastreams and data products are available and where outages have occurred.  At a high level, his presentation showed a remarkably continuous record over which high-quality data from SAIL is available for the scientific research community.

Following up on that presentation, Dr. Scott Collis of Argonne National Laboratory (ANL) presented an overview of the development of SAIL snowfall retrievals that he is leading in conjunction with a development team at ANL.  He showcased several sample products and, in a happy coincidence, was able to report that the SAIL snowfall retrievals that his team developed has just been approved for dissemination by the ARM data team and were now available for download on ARM Data Discovery.

There was then three brief presentations given by individuals who have guest instruments supported by the SAIL Campaign.  Professor Aaron Kennedy of the University of North Dakota presented on his deployment of two snowflake cameras, Dr. Ezra Levin presented on Handix Scientific’s deployment of a distributed array of aerosol sensors associated with SAIL-Net, and Dr. Brian Zerinsky of the University of Utah presented on his deployment of a Snow Pixel instrument.

Next, Professor Venkatachalam Chandrasekar of Colorado State University presented on behalf of the SAIL precipitation process sub-group, which consists of himself, Scott Collis of Argonne National Laboratory, Jiwen Fan of Pacific Northwest National Laboratory, Matt Kumjian of the Pennsylvania State University, and Adam Varble of Pacific Northwest National Laboratory, and he gave an overview of the precipitation process studies that SAIL is enabling.  He showed details of how SAIL and SPLASH X-band radars are collecting coordinated data, and how that enables detailed exploration of how storms develop in the SAIL study area.  He showed that observations of a thunderstorm in the fall of 2022 appear to show a different development life cycle from the canonical and classical development that is described in widely cited publications, such as in Wakimoto, 1982 (Monthly Weather Review).  Chandra mentioned that more analysis is needed to determine if this observation indicates that the terrain in the SAIL study area produces a fundamentally different life cycle of thunderstorm development. 

Next, Dr. Allison Aiken of Los Alamos National Laboratory provided an overview of her team’s work on ongoing and planned aerosol process studies in the SAIL study area.  Her work focuses on aerosol regimes (thereby specifically supporting SAIL science objectives), and she presented analysis of an intercomparison between the Wideband Integrated Bioaerosol Sensor (WIBS) guest instruments she deployed to SAIL in 2022 at SAIL’s M1 (Gothic) and S2 (Crested Butte Mountain) sites.  She showed that PM1 observations are well correlated between these two sites but that PM1 has a diurnal cycle at M1 that does not occur at S2, likely due to local sources. Furthermore, she showed that PM10 observations are not well correlated between the two sites, indicating that PM1 observations are widely representative of larger aerosol regimes whereas PM10 observations are more local.  She furthermore showed preliminary results from test-flights of the tethered balloon system that highlighted its measurement of the vertical and temporal evolution of an aerosol plume that arrived at the East River Watershed that likely was the result of long-range transport of a biomass burning event.  Her presentation showed the very large amount of detail on aerosol distribution, size, composition, optical properties, hygroscopicity, and sources that is being collected as part of SAIL.  Finally, Dr. Aiken briefly mentioned the three upcoming deployment of the tethered balloon system to SAIL in support of her selected FICUS proposal.

Next, Dr. Tom Hill of Colorado State University presented work that he, Carson Hume, and Jessie Creamean have done for collecting and measuring ice-nucleating particles at SAIL.  This presentation was focused on the details of data collection but did highlight the seasonal cycle of INPs observed to date and indicated that explanations of these findings were not immediately apparent and thus would require scientific studies.

The subsequent presentation was given by Dr. Jiwen Fan of the Pacific Northwest National Laboratory.  She talked about her planned aerosol-precipitation studies, including how the SAIL observations can directly address the current controversy in the published literature on the influence of CCN and INP on precipitation by determining the relationships between local-scaled CCN and INP concentrations and large-scale dynamic and thermodynamic conditions. She furthermore talked about how the observations to date can be used to test LES models and evaluate E3SM.

The next presentation was delivered by Professor Jim Smith of the University of California-Irvine.  Professor Smith presented the observational evidence collected by SAIL of numerous new-particle formation events in the spring of 2022.  These data showed frequent biosphere-atmosphere interactions in the spring of 2022 and were marked by an increase in organics and a reduction in sulfates.  He also showed that planetary boundary-layer dynamics play a significant role in diluting new-particle formation.

The final presentation was delivered by Dr. Maria Zawadowicz of Brookhaven National Laboratory. She presented on her work with the deployment of an aerosol chemical speciation monitor as part of SAIL and discussed how that instrument works and what has been found so far, particularly identifying the time and chemical evolution of biomass burning events that have occurred upwind of SAIL since the start of the campaign.  Finally, Dr. Zawadowicz briefly mentioned the three upcoming deployments of the tethered balloon system to SAIL in support of her selected FICUS proposal.

The audience was polled about the preferred directions for the remainder of the session.  The audience overwhelmingly felt that it was important to discuss the mysteries of precipitation and aerosol processes that appear to have been revealed by SAIL and SPLASH data.  Therefore, the last quarter of the breakout session focused on the mysteries raised by the data analysis presented by Chandra, Allison Aiken, Jim Smith, and Maria Zawadowicz.

Key Findings

The data records from SAIL, SPLASH, and guest instruments are remarkably complete to date and are of a quality to enable scientific investigations that support SAIL’s science objectives.

  • There is significant scientific interest in SAIL and SPLASH data to undertake a wide range of research activities that support ASR’s mission.

  • The SAIL data have revealed several mysteries to date, including on thunderstorm structure and evolution and new-particle event formation.

  • Collaboration between SAIL and SPLASH research on specific research activities is showing scientific potential, and in some cases, scientific results, and generally requires interdisciplinary research activities.


The process of chairing a hybrid breakout session was considerably (and surprisingly) more complex than chairing an in-person or virtual meeting separately.  While the online training activities to prepare session conveners for the hybrid format were helpful, this session’s conveners would have benefitted from a 15-minute dry-run with the audiovisual technical support staff prior to the breakout session to gain familiarity with the AV equipment, transition between in-person presentations and those with remote participants, and plan for fielding questions from individuals in the room and online.





Future Plans

The SAIL and SPLASH campaigns will continue to collect data through much of FY23.  Numerous research activities are already underway and a number of exciting activities are nascent, including those that may be enabled by the ASR’s FOA-2850.  Research surrounding the mysteries, especially whether they will persist throughout the duration of the SAIL and SPLASH campaigns and implications of persistence or lack thereof, is encouraged.

Action Items

The SAIL and SPLASH Principal Investigators will explore a time to focus on coordinated science activities between SAIL and SPLASH researchers, especially regarding those activities that cannot be easily accomplished by individuals but rather require coordination and teamwork among researchers on SAIL and SPLASH simultaneously.  A workshop may be required to translate the findings from the Integrated Mountainous Hydroclimate (IMHC) workshop to specific activities with SAIL and SPLASH data, including where there are opportunities that can take advantage of campaign configurability before both of these campaigns conclude in FY23.