Breakout Summary Report
ARM/ASR User and PI Meeting
13 - 17 March 2017
16 March 2017
10:45 AM - 12:45 PM
75
Angela Rowe and Zhe Feng (with notes provided by Yolande Serra, Samson Hagos, and Casey Burleyson)
Breakout Description
During last year’s Atmospheric System Research (ASR) Convection Workshop, major gaps in the understanding of convective processes were identified, focusing primarily on the transitional phases: boundary-layer variability to shallow clouds, shallow-to-deep transition, and upscale growth/convective organization. The overarching challenge is to determine the environmental conditions and feedback processes controlling these transitions. A list of short-term priorities using existing Atmospheric Radiation Measurement (ARM) Climate Research Facility infrastructure to address these challenges was constructed during the workshop, as well as longer-term observational needs. This breakout session will summarize this discussion from the workshop and provide a venue to discuss additional needs within the community to increase understanding of transitional convective processes.Main Discussion
The goal of this breakout session was to summarize for a broader audience the convective transition discussions from the ASR-sponsored Convection Workshop in February 2016 and to provide a venue to discuss additional observational needs within the ARM/ASR community for increasing understanding of transitional convective processes. Presentations and discussions were focused around short-term strategies to address these needs, including merged products from existing data sets and agile/adaptive radar operations. Presentations were selected to highlight mid-latitude continental, tropical oceanic, and tropical Amazon observations. Each presenter was asked to address the following questions:
- How do existing data products from the ARM field campaign/site address your science questions related to convective transitions? Which data products were especially helpful?
- What additional (merged) data products could be created from existing data to address your science question(s)?
- What additional observations do you wish were/could be collected to address remaining questions?
These questions then served as discussion points for the remaining hour of the session. To start the discussion, a wish list of data products from the presentations was summarized, highlighting the need for concurrent observations of microphysics, drafts, and environmental conditions in these varying regions. The desire for vertical profiles of environmental moisture across many timescales was emphasized, as well as products characterizing cloud and precipitation morphology and organization. While individual principal investigators have gridded and merged radar data from select ARM sites/field campaigns, there is a need for these products to be generated for all sites/radars, as well as for higher-order statistical information from these data sets (e.g., distributions of echo-top height, cell sizes, cell evolution). The discussion then converged on the need to improve the metadata of current data sets for searching specific cases/event types. In addition, a significant portion of the discussion focused on the need for high-resolution measurements of evolving convective cells through possible adaptive/agile radar scanning.
Key Findings
There was consensus among session participants that our community would greatly benefit from ARM data being packaged by event. This searchable catalog of events (instead of grouping by field campaigns or data sources) would be especially helpful for multi-instrument analyses of specific cases or phenomena. For this group in particular, tagging events based on echo-top heights or cloud-type classification (e.g., to isolate the occurrence of shallow clouds), HID statistics (presence of hail?), rain rate thresholds, presence of mesoscale convective systems, etc., would be helpful for describing convective transitions. This searchable metadata also could be grouped based on large-scale environmental conditions, which could be linked to merged radar cell tracking (e.g., via the Python-ARM Radar Toolkit).
In addition, a strong case was made for adaptive/agile radar scanning strategies that was motivated, in particular, by biases in vertical velocities simulated by convection-permitting models. Radar simulators applied to convection-permitting models could be useful to test and design radar scanning strategies. The upcoming deployment of a C-band ARM precipitation radar (C-SAPR2) during the Cloud, Aerosol, and Complex Terrain Interactions (CACTI) field campaign would be an excellent opportunity to apply this cell tracking scanning strategy.