In January 2011 NOAA's Air Resources Laboratory assumed oversight of speciated atmospheric mercury measurements at the Mauna Loa Observatory (MLO), and the site joined the National Atmospheric Deposition Program's (NADP) Atmospheric Mercury Network (AMNet). MLO is one of six NOAA baseline monitoring stations for the study of the background global atmosphere, and is located at an elevation of 3,397 m on the northern slope of the Mauna Loa volcano on the Big Island of Hawaii. A single Tekran speciation system measures gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and particulate-bound mercury (PBM) with nominal 1-hr resolution. Since 2011, measurements of ozone (O3), sulfur dioxide (SO2), and carbon monoxide (CO) were also added. The site is an ideal high-altitude location from which to monitor the global background atmosphere. Free tropospheric flow at the elevation of MLO is typically from the east and northeast (trade wind circulation), with local upslope/downslope circulation superimposed on the larger-scale flows. Measured mercury species concentrations will be presented with respect to diurnal, seasonal, and annual variations, and trends in mercury concentrations at the site will be discussed. Source regions associated with both high and low mercury concentrations will be investigated through gridded trajectory frequency analysis using NOAA's HYSPLIT model. Finally, a brief summary of measurement accuracy assessment activities will be presented.
|Original language||English (US)|
|Title of host publication||AGU Fall Meeting Abstracts|
|State||Published - Dec 1 2018|