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Alice Crawford attended a teleconference to close out the U.S. Department of Energy (DOE) ashfall project on February 20th. This project was a collaboration between the DOE Office of River Protection (ORP), NOAA’s Air Resources Laboratory, the U.S. Geological Survey (USGS), and the Desert Research Institute (DRI) to estimate concentrations of airborne ash that might be expected at the DOE Hanford site if an eruption of Mount St. Helens were to occur. DRI, USGS, and NOAA ARL each submitted a final report in the spring of 2018. In the fall, report authors responded in writing to questions from a peer review and from the Defense Nuclear Facilities Safety Board, DNFSB. The teleconference allowed a detailed oral discussion of DNFSB’s questions with DNFSB, DOE ORP, and the report authors.

Winston Luke is traveling to the Grand Bay National Estuarine Research Reserve in Moss Point, Mississippi for a quarterly maintenance visit February 25 – March 1. He will repair, maintain, and calibrate instrumentation to measure trace gases (ozone, sulfur dioxide, carbon monoxide, mercury species), aerosols (black carbon), meteorological parameters (wind speed and direction, temperature, pressure, relative humidity, rainfall rate, incoming solar radiation), and to collect precipitation samples for analysis of mercury and major ions. He will also collaborate with faculty and students from the University of Mississippi to investigate the performance of passive samplers for gaseous elemental mercury.

ATDD
From 18-24 February, Temple Lee and Michael Buban participated in two intensive observation periods (IOP) of the Meso 18-19 field experiment, which is a continuation of the Verification of the Origins of Rotation in Tornadoes Experiment in the Southeast U.S. (VORTEX-SE) program focused on improving scientific understanding of severe weather genesis over the southeastern U.S. During the two IOPs, Temple and Michael launched weather balloons from Montgomery, Alabama. Data from these launches were assimilated into operational weather forecast models and were used by the Storm Prediction Center and local National Weather Service (NWS) offices for real-time weather forecasts.

A paper entitled “Contrasting air mass advection explains significant differences in boundary layer depth seasonal cycles under onshore versus offshore flows” by Sandip Pal (Texas Tech University) and Temple Lee was accepted for publication in Geophysical Research Letters. In the paper, Temple and Sandip used 25 years of boundary layer depths calculated using rawinsonde launches from 18 coastal sites along the Atlantic Ocean, Pacific Ocean, and Gulf of Mexico. Temple and Sandip found that offshore winds resulted in deeper boundary layers than onshore winds, and this difference was largest during the spring and summer at sites located along the Gulf of Mexico and Atlantic Ocean. The results underscore the importance of advection on boundary-layer depth footprints and provide observational constraints to assist in model evaluation.