ARL Weekly News – November 16, 2018

At the 2018 Fall Meeting of the National Atmospheric Deposition Program (NADP), Winston Luke was elected to serve as Secretary of the Network Operations Subcommittee (NOS) of NADP. The NOS oversees field-siting criteria and laboratory and sample collection protocols, and evaluates equipment and record keeping methods. After serving for one year as Secretary, Dr. Luke will serve a second year as Vice Chair, and a third year as the Chair of the NOS.

The latest paper resulting from FRD’s Project Sagebrush tracer experiments has now been officially published: Finn, D., R.M. Eckman, Z. Gao, and H. Liu, 2018: Mechanisms for wind direction changes in the very stable boundary layer. J. Appl. Met. Clim., 57, 2623-2637. doi: 10.1175/JAMC-D-18-0065.1

FRD uses limited quantities of compressed hydrogen gas in its tracer laboratory to operate the trace gas analyzers (TGAs) that measure concentration fluctuations. A question has been raised whether the use of compressed hydrogen requires the installation of a room sensor to measure hydrogen concentrations approaching flammability limits. OSHA regulations do not appear to require such a sensor. In fact, the OSHA regulations specifically for compressed hydrogen come into effect only when storage amounts are above 400 cubic feet; FRD’s storage quantities are below this limit. Since the TGAs are currently not in use, the existing hydrogen cylinders have been moved out of the tracer laboratory to FRD’s warehouse area as an additional precaution.

A group of approximately 50 homeschooled students and their parents from several East Tennessee cities and towns visited the ATDD facility on November 14, 2018 for one of their “Wide World Wednesdays” field trips. The students, ages 5-11, learned about current NOAA research at the lab and engaged in hands-on activities, including graphing wind speeds, measuring thermal and infrared temperatures and rainfall.

An article entitled “The Particle Dry Deposition Component of Total Deposition from Air Quality Models: Right, wrong or uncertain?” has been accepted for publication in Tellus B: Chemical and Physical Meteorology. The work, authored by Rick Saylor (ATDD), Barry Baker (HQ), Pius Lee (HQ), Daniel Tong (HQ), Li Pan (NCEP) and Bruce Hicks (Metcorps), found that the choice of particle dry deposition algorithm in air quality models has a substantial impact on the magnitude of simulated particle deposition predicted by those models. In locations where particle dry deposition is a significant portion of total deposition (e.g., in portions of the Western U. S.), the choice of algorithm may also affect total deposition estimates from air quality models. The article also notes other uncertainties inherent in modeled dry deposition that may impact total deposition, thereby calling into question the use of these deposition estimates for critical loads analyses. For more information, contact Rick Saylor (