Breakout Summary Report

ARM/ASR User and PI Meeting

19 - 23 March 2018

Session Title: GoAmazon2014/5 Synergies II
Session Date: 20 March 2018
Session Time: 1:30 PM - 3:30 PM
Number of Attendees: 25
Summary Authors: Yolande Serra and Angela Rowe

Breakout Description

This session follows up on last year’s GOAmazon breakout session and focuses on the following questions: How have new PI products using GOAmazon data sets helped contribute to our understanding of Amazonian chemical, water, and energy cycling? How have they contributed to validation and model improvement of the convective life cycle in the Amazon? How can we work together to continue to make the most of GoAmazon field campaign observations and data products?

Main Discussion

The session discussions included (1) updates on products available since last year’s GOAmazon session, many not yet uploaded to the ARM Data Center; (2) issues with large-scale gridded products over the study region; (3) need to understand the large-scale forcing that both observational and regional modeling studies suggest is important to the convective development, including aerosol effects, over the region.

Key Findings

• Updating SIPAM data based on new calibrated TRMM/GPM data results in an increase in SIPAM precipitation leading to an increase in upward motion in VARANAL.
• Studies using a new Parsivel disdrometer PI product reveal wind direction has a strong impact on drop size distributions, with more oceanic DSDs being more consistent with shallower clouds, while non-oceanic DSDs are more consistent with deeper convective clouds (Wang et al. , 2018). Die noted that an ARM VAP for Parsivel data is coming soon (including both the source code of PyDSD and the output as a VAP).
• Convective downdrafts can be identified in the surface data, using SIPAM to verify the events associated with the downdrafts. Sophie Mayne is planning on providing this as a new PI Product by next year’s PI Meeting.
• Kelvin and westward inertial gravity (WIG) waves are associated with enhanced rainfall and tropospheric moisture during their active phases, as well as affecting large-scale wind fields over the region. Kelvin and WIG indices are available from Yolande Serra for investigators interested in the impacts of these waves on their data sets.
• Based on convective-permitting-scale WRF simulations over the region, Zhe Feng finds shallow clouds dominate the surface-cloud radiative forcing in all seasons. Zhe suggests that understanding the interactions between large-scale winds and local boundary-layer processes is likely key to understanding the diurnal cycle of convection in Amazon.

Issues

The ongoing issue for the GOAmazon region, discussed at both this year’s and last year’s breakout session, is the disparity between the ECMWF analyses and the radiosondes launched during GOAmazon, making it difficult to incorporate the radiosonde observations into the variational analysis product. Shuaiqi continues to investigate statistical approaches to work around this issue in order to assimilate the radiosonde observations into the variational analyses. The group noted the lack of global modeling studies for the GOAmazon region. Only one study using the MPAS model could be identified.

Needs

• A list of explicit or parameterized representation of cold pools from high-resolution model simulations to compare with Sophie’s observational database.
• Incorporation of microphysical and aerosol data into cloud products for better model validation. The G-1 aircraft microphysics measurements of shallow clouds throughout the 2014-15 period are available from Jennifer Comstock. Delta deuterium and other standard ARM microphysical measurements are also available on the ARM Data Center and could be used towards a combined microphysical/cloud product.
• A uniformly agreed-upon case/day classification for the 2014-15 time period over the GOAmazon region that can be used by investigators for efficiency and for improved understanding of both aerosol and convective studies of similar cases/convective classifications.

Decisions

This session, as well as last year’s session, has been helpful for organizing ongoing studies of the GOAmazon region and making more efficient use of standard and PI products, as well as modeling tools, to address more complex questions regarding convective development and associated aerosol effects over the region. Better coordination among the group in terms of case/day selection was noted as a priority moving forward.

Future Plans

• Attendees agreed to keep working together to avoid duplicating efforts on studies with similar goals. Instead, teams will combine resources where possible to address ongoing scientific questions for the region. See action item 5 below on synergistic study activity.
• Compare the ground-based precipitation data with the SIPAM V2 radar rain rates (Scott Giangrande and Courtney Schumacher).
Shuaiqi plans to continue developing the variational analysis product by assimilating satellite TOA fluxes and surface-station observations from CHUVA for the entire 2014-15 period.
• Yolande Serra, Angela Rowe, Zhe Feng, and Samson Hagos will collaborate to better understand the impacts of large-scale waves on convective development via joint observational and modeling studies.
• Yolande Serra, Angela Rowe, Die Wang, and Scott Giangrande will collaborate to better understand impacts of waves on DSDs in disdrometer product.
• Jerome Fast will continue to develop the GOAmazon Testbed concept given the overall support for this idea during the session.

Action Items

1) There was consensus that the forcing data provided by Shuaiqi should include the observed surface fluxes and satellite data for the entire 2014-15 period, rather than just for the two IOPs.
2) Sophie Mayne plans on releasing a cold pool/downdraft database by next year’s PI Meeting.
3) PI product discussed in Giangrande et al. (2017) not yet uploaded will be added to the ARM Data Center in the coming months.
4) Develop a campaign wiki or public website with a case/day classification table for GOAmazon. Get help from ASR staff to implement this as part of the GOAmazon project website.
5) Investigators interested in synergistic studies should email Yolande Serra (yserra@uw.edu), who will compile a group discussion page on this issue.