Breakout Summary Report
ARM/ASR User and PI Meeting
13 - 17 March 2017
15 March 2017
10:30 AM - 12:30 PM
25
Greg McFarquhar
Breakout Description
Greg McFarquhar provided an overview presentation of the proposed Cold-air Outbreak in the Marine Boundary Layer Experiment (COMBLE). Thereafter, there was discussion about the proposed campaign, including optimum siting. Ann Fridlind presented a description on modeling challenges for simulating cold-air outbreaks, and Mike Jensen, on behalf of Steve Abel, gave an overview on observations and modeling efforts for cold-air outbreaks underway in the United Kingdom. Finally, Mikhail Ovchinnikov led discussion about possible modeling efforts to be associated with COMBLE.Main Discussion
It was noted a need exists to differentiate COMBLE from previous, similar campaigns in the area, including Arctic Research of the Composition of the Troposphere from Aircraft and Satellite (ARCTAS) and CONSTRAIN. The biggest issue with simulations in this region is the representation of mixed-phase microphysics and the interaction with the mesoscale.
It was emphasized that measurements over the sea ice (in an originating area of cold-air outbreak) is critical to success of the campaign. The Polarstern (Multidisciplinary Drifting Observatory for the Study of Arctic Climate, or MOSAIC) may be too far away to be useful for this purpose. The coastline at Andenes/Nordkapp is extremely steep and likely represents a serious orographic issue. How this will impact the cloud properties observed at the Atmospheric Radiation Measurement (ARM) Climate Research Facility mobile facility, and how representative these measurements will be for the target cloud types, needs to be determined.
Participants thought that scanning radar systems will have an unobstructed 180-degree view, but there will definitely be upwind orographic effects. It was discussed whether a deployment in the Aleutians should be considered.
Discussions on the role of unmanned aerial systems (UAS) also took place, including a discussion on the target measurement for UAS observations, namely that vertical structure of aerosols and thermodynamics, and open ocean surface fluxes, are possibilities. The surface heterogeneity from Svalbard to the ice sheet could be an important role for UAS.
The need for coordinating with an Office of Naval Research effort in the same time frame in the region of Polarstern was noted.
It was questioned whether a tethered balloon system had been considered, perhaps with a video ice particle sampler at Bear Island on a tethered balloon. It was agreed this was unlikely.
Surface momentum fluxes and surface wind speed are major biases in weather models in this region. Bear Island likely has a significant impact on the flow pattern (560 m maximum elevation). Need to consider how this will be addressed.
It was noted that surface heat fluxes in addition to momentum fluxes are needed. UAS may be useful for this. Would dropsondes help? Are flux buoys a possibility?
Finally, from the global climate model perspective, characterizing the presence of super-cooled water and phase partitioning would be critical outcomes.