Analysis of Long term Measurements of Trace Species at 20°, 40° and 76° North

James W Hannigan, National Center for Atmospheric Research, Atmospheric Chemistry Observations & Modeling Laboratory, Boulder, CO, United States, Ivan Ortega, Univ of Colorado, Boulder, CO, United States and Rebecca R Buchholz, NSF National Center for Atmospheric Research (NSF NCAR), Atmospheric Chemistry Observations & Modeling (ACOM) Laboratory, Boulder, United States