Regional and hemispheric influences on temporal variability in baseline carbon monoxide and ozone over the Northeast US

Abstract

Interannual variability in baseline carbon monoxide (CO) and ozone (O), defined as mixing ratios under minimal influence of recent and local emissions, was studied for seven rural sites in the Northeast US over 2001 - 2010. Annual baseline CO exhibited statistically significant decreasing trends (-4.3 - -2.3 ppbv yr), while baseline O did not display trends at any site. In examining the data by season, wintertime and springtime baseline CO at the two highest sites (1.5 km and 2 km asl) did not experience significant trends. Decadal increasing trends (~2.55 ppbv yr) were found in springtime and wintertime baseline O in southern New Hampshire, which was associated with anthropogenic NO emission reductions from the urban corridor. Biomass burning emissions impacted summertime baseline CO with ~38% variability from wildfire emissions in Russia and ~22% from Canada at five sites and impacted baseline O at the two high elevation sites only with ~27% variability from wildfires in both Russia and Canada. The Arctic Oscillation was negatively correlated with summertime baseline O, while the North Atlantic Oscillation was positively correlated with springtime baseline O. This study suggested that anthropogenic and biomass burning emissions, and meteorological conditions were important factors working together to determine baseline O and CO in the Northeast U.S. during the 2000s.

An Overview of Atmospheric Features Over the Western North Atlantic Ocean and North American East Coast – Part 1: Analysis of Aerosols, Gases, and Wet Deposition Chemistry

“…Several studies have examined the interannual variability of CO by using 3‐D modeling or ground measurements like the ones provided by the National Oceanic and Atmospheric Administration (NOAA) Climate Monitoring and Diagnostics Laboratory (CMDL) air sampling network (e.g., Duncan & Logan, 2008; Novelli et al., 1998; Novelli et al., 1992; Wotawa et al., 2001; Y. Zhou et al., 2017). Our study builds on past works by using seasonally averaged tropospheric CO column from MERRA‐2 from 2014 – 2018 (Figure 3) to analyze the changes in CO specifically over eastern North America and the WNAO.…”

“…Several studies have examined the interannual variability of CO by using 3-D modeling or ground measurements like the ones provided by the National Oceanic and Atmospheric Administration (NOAA) Climate Monitoring and Diagnostics Laboratory (CMDL) air sampling network (e.g., Duncan & Logan, 2008;Novelli et al, 1998;Novelli et al, 1992;Wotawa et al, 2001;Y. Zhou et al, 2017).…”

An improved estimate for the <i>δ</i><sup>13</sup>C and <i>δ</i><sup>18</sup>O signatures of carbon monoxide produced from atmospheric oxidation of volatile organic compounds

“…In order to obtain a best-fit solution using Eq. (4) for all the data, we regressed the numerator against the denominator using an ordinary least-squares (model 1) Y |X approach (Isobe et al,1990;Zobitz et al, 2006).…”

Impacts of large-scale circulation on urban ambient concentrations of gaseous elemental mercury in New York, USA

“…S5). Zhou et al (2017) suggested that baseline CO in rural northeastern US areas was controlled by a multitude of factors, including global biomass emissions, large-scale circulation, and cyclone activity. At the Bronx site, the low percentile value, close to regional baseline levels, was possibly determined by a range of factors, whose importance could have varied from year to year.…”