Breakout Summary Report

ARM/ASR User and PI Meeting

Breakout Description

This session has two primary goals. The first is to inform the ARM/ASR community of available CACTI data sets that may be useful to them in their own research pursuits. A particular focus will be LASSOCACTI ensembles and LES simulations that have been completed and will be fully available for the community. The second is to highlight recent or planned CACTI research conducted by the community with discussion of potential collaborations moving forward.

Main Discussion

This session had two primary goals. The first was to inform the ARM/ASR community of available CACTI data sets that may be useful to them in their own research pursuits. A particular focus was LASSO-CACTI ensembles and LES simulations that have been completed and will be fully available for the community. The second was to highlight recent or planned CACTI research conducted by the community with discussion of potential collaborations moving forward.

Two overview talks were given over the first 50 minutes of the session. The first, by Adam Varble (PNNL), provided an overview of CACTI data sets, ongoing research, and future research opportunities. The second, by Bill Gustafson (PNNL), discussed the status and plans of the LASSO-CACTI simulations. A series of ongoing research talks were then given by Zhe Feng (PNNL), Jim Marquis (PNNL), Scott Powell (NPS), Neil Lareau (U. Nevada, Reno), and Yayun Qiao (U. Oklahoma) on topics ranging from aircraft in situ microphysical measurements to orographic flow structures to deep convection initiation and growth. We ran out of time for group discussions, but some small groups of individuals had discussions following the session on possible collaborative work.

Key Findings

There is a lot of ongoing CACTI research focusing on controls of shallow to deep convection transitions at PNNL and a few universities using a combination of observations and simulations including LASSO with potential for greater communication and collaboration between these groups. Radars went through rigorous absolute, relative, and cross-calibration, leading to some of the best data sets ever collected by ARM, with a wealth of information. This supported the production of several radar-based products including a database of tracked convective cells tagged with satellite retrieval and environmental properties that is available now along with the tracking software. Work is ongoing to make additional products available through the ARM Data Center. Deep convective upscale growth is another area of active research at PNNL and at least one university.

While there has been some aerosol-cloud interaction research with respect to shallow and deep clouds at both PNNL and a university, there is potential for much more research in this area given the unique data sets collected during CACTI. Some research is planned at PNNL with respect to precipitation and ice initiation as influenced by aerosols and interactions between convective cells, as this appears to be biased in models for moderate depth clouds common during CACTI. Outside of a university-led study on ice nucleating particles (INP), little research has been done yet on aerosol processes, making this an open opportunity for researchers. The so-far-little-used aircraft measurements could be particularly valuable for studying aerosol and aerosol-cloud interaction processes given the established differences in cloud and aerosol properties at this location relative to other ARM sites. 

Although the deep convection during CACTI has received the most attention, there is great potential to study shallow cloud life cycles including interactions with aerosols and orographic circulations, particularly since the scanning cloud radar data set is one of the best collected by ARM. Indeed, it was surprising just how many shallow clouds were visible and forming drizzle during CACTI, in stark contrast to SGP, with comprehensive aerosol measurements available to connect to cloud properties. With no firm research plans in this area, this presents a great opportunity for teams interested in this topic. There are also large amounts of unique scanning-radar hemispheric RHI scans at Ka-, X-, and C-band frequencies and some IOP manually tracked convective cells waiting to be mined. The high resolution of these scans can be used to analyze detailed cloud dynamical and microphysical processes in the context of cloud macrophysical life cycle from radar PPI and 1-minute GOES16 imagery, using LASSO simulations to fill in the gaps and elucidate sources of model biases.

The LASSO-CACTI library of mesoscale ensembles and large-eddy simulations of CACTI cases is currently available as a beta release and users are beginning to work with it. The full release is expected early this coming year. Researchers working with the data to date have focused on tracking convective cells and the impacts of detailed orographic circulations and entrainment rates on their impact on convective initiation. Many more opportunities exist to mine this one-of-a-kind data set.

Issues

Microphone problems resulted in the session starting 10 minutes late, which contributed to a lack of time for group discussion.

Needs

A professor expressed interest in using LASSO-CACTI data and ARM computing resources in a classroom setting for teaching a graduate-level numerical programming class. He would like to have the class access the data via ARM’s computing resources and would like assistance making this happen. A fast, efficient way will be needed to onboard students with their accounts and handle foreign national reviews.

Decisions

N/A

Future Plans

There were clear connections that could potentially be made between complementary ongoing and planned research by Jim Marquis, Scott Powell, Neil Lareau, and Dan Kirshbaum on processes controlling the transition from shallow to deep convection during CACTI.

CACTI is one of several locations where SCREAM will be evaluated in the THREAD SFA at LLNL with some focus on both shallow and deep convective clouds, and there is potential for collaboration between institutions on this topic.

Action Items

N/A