Breakout Summary Report
ARM/ASR User and PI Meeting
13 - 17 March 2017
Cloud, Aerosol, and Complex Terrain Interactions (CACTI)
13 March 2017
1:30 PM - 3:30 PM
50
Adam Varble
13 March 2017
1:30 PM - 3:30 PM
50
Adam Varble
Breakout Description
The primary purpose of this session was to introduce interested members of the ARM and ASR communities to the ARM-funded CACTI field campaign, which will take place between August 2018 and April 2019 near Cordoba, Argentina. Issues in the future planning of the campaign, including observing strategies and field campaign requests, were primary discussion topics.Main Discussion
The session consisted of a long-overview talk by principal investigator Adam Varble discussing motivation for CACTI, primary science questions, and experimental design. A second presentation was then given by Kim Nitschke, Los Alamos National Laboratory, overviewing the logistical timeline ahead of CACTI along with the proposed site layout. CACTI co-investigator Steve Nesbitt gave a talk overviewing the motivation, science questions, and experimental design of the RELAMPAGO field campaign, which was recently funded by NSF, and will overlap with the CACTI intensive operational period and observing region. Following this, Nitin Bharadwaj gave an update on the C-SAPR2 radar, and Paloma Borque discussed the capabilities of the X/Ka-SACR. Lastly, Sue van den Heever discussed a potential deployment of hectacopter drones during the CACTI IOP for measuring boundary-layer thermodynamic and aerosol profiles.Much of the discussion focused on ARM IOP requests, including unmanned aerial systems (UAS) and GPS sensors with surface meteorological stations for measuring total column water. Both of these deployments would provide mesoscale context for conditions at the AMF1 site. In the case of GPS sensors, they could be added to existing meteorological stations or meteorological stations could be added to potentially pre-existing GPS stations. These would require minimal setup and maintenance. Yolande Serra and Henrique Barbosa are leading the effort to investigate possibilities for adding meteorological stations and/or GPS sensors as an ARM IOP deployment. In the case of UAS, a deployment is much more complicated because of restrictive UAS flight regulations and the necessity of operators for each UAS. Offline ARM IOP discussions have also included interest in deploying additional surface meteorological stations up to the ridgeline west of the AMF1, a Raman lidar at the AMF1 or C-SAPR2 site, and an addition scanning, dual-polarimetric C-band radar maintained by Colorado State University.
Key Findings
C-SAPR2 is being tested at the SGP site and should be ready for deployment to CACTI, but a radome will need to be designed to protect it from hail and the setup (e.g., on a trailer or on container tops) and location of the deployment is not yet decided.The W/Ka-SACR has been replaced by the X/Ka-SACR because it will not significantly affect the proposed science and has a higher probability of functioning well since it is not currently deployed, but at PNNL being worked on and tested.
It now appears that the WACR will not be able to be deployed, and deployment of an Aerodynamic Particle Sizer (APS) will be difficult because of the intensiveness of APS measurements. This leaves an aerosol observation weakness of no large aerosol size distributions, which could be important for measuring dust and salt in some situations. Other possibilities for measuring the sizes of aerosol particles larger than a micron may need to be explored.
Issues
A continuing concern is the availability of the Gulfstream-1 aircraft in late 2018 for in situ measurements of (1) the evolving free troposphere that will be only discretely measured in space or time from the ground, (2) free tropospheric aerosol properties being ingested and detrained from clouds, and (3) cloud properties that will be crucial for validating and tuning radar retrievals. The deployment of the G-1 will ultimately depend on the ARM budget, which is not yet known.Radar scanning will focus on observing evolving convective dynamical and microphysical processes in high resolution, both spatially and temporally, but this is much more efficient with a cell-tracking algorithm that does not yet exist for ARM radars. Without one, a larger region needs to be scanned as the exact location of convective cells in any given situation is unknown. It may be possible to write and test single- and multi-radar algorithms before CACTI using radars at the SGP site, as many in the ARM and ASR community are interested in having such algorithms for long-term ARM sites and future ARM field campaigns where high-resolution measurements of the evolution of individual clouds and precipitation cells are important. Tracking the interactive processes between cloud microphysics and dynamics in the context of environmental condition measurements is deemed essential to improving model parameterizations and moving beyond already well-established statistical model cloud and precipitation structural biases, but this will require an ARM IOP request and dedicated time from ARM engineers to implement an algorithm into a radar such as C-SAPR2. This IOP request may be submitted soon with the hope that this process can be completed before CACTI.
Information on DOE UAS regulations for ARM deployments is needed to plan for potential UAS involvement in CACTI.
Future Plans
Any ARM IOP requests that are deemed feasible will be completed and submitted this year, preferably before the end of May. An additional site survey trip to Argentina may be needed to figure out C-SAPR2 and stereo camera locations.A RELAMPAGO dry run is planned for November 2017, which will involve testing of coordination between CACTI and RELAMPAGO teams. An additional pre-campaign meeting to fine tune the communications and decision making framework that will be used during CACTI may also be planned.
A CACTI session will be planned for the next ARM-ASR PI Meeting in early 2018 when most of the campaign logistics should be solidified, and final details regarding observing strategies and communications between the science team, site technicians, and the RELAMPAGO science team during the IOP will be ironed out.