Breakout Summary Report

Breakout Description

The goal of this session is to provide an opportunity for scientists to describe the use of ARM lidar data in their research, and to provide a forum to discuss challenges associated with the use of that data. Brief instrument and VAP updates will be provided along with plans for relocating existing instrumentation, new instrument procurements, and VAP development. The primary focus of this session will be on science applications of the various ARM lidar systems (e.g., Doppler, Raman, and HSRL, MPL, ceilometer).  Short flash talks are solicited on a wide range of topics, including (but not necessarily limited to) the following:

1. Cloud and aerosol properties as retrieved from the lidar data


2. Lidar observations of the boundary layer


3. Applications of edge computing, and machine learning


4. New measurement techniques


5. Lidar observations of the polar environment


6. Temperature and humidity profiling


7. Model verification and data assimilation

Main Discussion

The session was advertised as an opportunity for scientists to describe how they use ARM lidar data in their research, and challenges associated with the use of that data.  The session started with brief updates on the Raman, Doppler, and HSRL systems from Rob Newsom and Ray Bambha. Damao Zhang then gave an update on the various lidar-related value-added data products. This was then followed by a series of quick ~5-minute talks, including the following:

• “Assessment of vertical CCN retrieval methods against in-situ CCN measurements from SGP”, by Gourihar Kulkarni


• “High-resolution lidar with a range resolution down to 10 cm”, by Fan Yang


• “Observations of Wind Farm Atmosphere Interactions within the American Wake Experiment,” by Patrick Moriarty (virtual)


• “Update on AWAKEN analysis” by Raghu Krishnamurthy


• “A comprehensive data set of Boundary Layer Height using Micropulse Lidar at multiple ARM sites,” by Natalia Henao, Tianning Su and Zhanqing Li

These talks covered topics ranging from CCN retrievals using Raman lidar-derived aerosol extinction data (in GK's talk) to boundary-layer depth estimation using MPL data. Two of the talks were on the AWAKEN project and thus focused on Doppler lidar wind measurements. One talk was more technical and described a prototype lidar that can observe cloud boundaries with very high resolution.

After the talks we went into the discussion phase, offering the following choices:

• Doppler lidar scan strategies


• Lidar simulators


• Applications of edge computing


• Cooperative lidar/aircraft measurements.

Unfortunately, we only had about 5-10 minutes left for discussion after the talks due to various technical issues (see below). We did, however, receive feedback on scan strategies and lidar simulators. Regarding lidar simulators, there is a need for both Doppler and (non-Doppler) elastic lidar simulators. We need to think about efficient methods of interpolating (or transforming) relatively coarse LES output to the lidar sample volume, enabling direct comparison between modeled and observed radial velocity fields. For (non-Doppler) elastic lidar simulation, atmospheric model output would also have to include sufficient information to compute the attenuated backscatter along the beam (aerosol number density, size distribution and refractive index).

Regarding scan strategies, new data products could potentially be developed if we expanded our Doppler lidar scanning strategies. Virendra Ghate suggested that we go ahead and modify our Doppler lidar scan strategies and let the science community figure out what to do with the data. As Doppler lidar scanning strategies become more complicated, Doppler lidar simulators can be used to enable direct comparisons between the modeled and observed radial velocity fields. Also, we received positive feedback from Dan Feldman regarding the implementation of more complex scanning strategies during SAIL (and EPCAPE). With that feedback, we are looking at expanding the number of scan types used at all sites and facilities in FY24.

Key Findings

N/A

Issues

We had some technical problems that consumed some valuable time. First, the presentation laptop (my laptop) lost power mid-way through GK's presentation. Turns out the laptop was plugged in but the power strip was switched off. We also experienced intermittent temporary drop-outs in our remote communications throughout the session.

Needs

N/A

Decisions

N/A

Future Plans

N/A

Action Items

Over the next year, the Doppler lidar mentors will design and implement new scanning strategies based on feedback from the participants in the breakout session.