Spring Ozone at Mount Washington Observatory: Implications for Stratospheric Intrusion US

Author: Yaping Xiao and Jennifer D. Hegarty
Date: 
November 3, 2008
Type: 
Presentation
Venue: 
AGU Meeting
Citation: 

Xiao Y.P., R. Talbot, J. Hegarty, et al., Spring O3 at Mount Washington Observatory: Implications for Stratospheric Intrusions, 2008 Fall AGU Meeting, San Francisco.

It is well known that tropospheric O3 peaks in late spring in most remote regions of northern mid- and high-latitudes, which has been attributed to: (1) meteorological process: mass transfer from the stratosphere to the troposphere peaks in spring and; (2) photochemical activity after accumulation of O3 and its precursors in winter and early spring. However, determining the relative contribution of chemical versus meteorological processes has been a research focus for over two decades.

The multi-year (2002-2006) record of O3 observations at Mount Washington Observatory (MWO, 44.3N, 71.3W, 1910m asl) from the AIRMAP program at the University of New Hampshire provides an opportunity to examine the anthropogenic and stratospheric contributions to springtime O3. In this work, we integrate the meteorological and chemical data to identify the synoptic conditions, which are favorable for stratospheric influence at MWO, and examine the frequency of stratospheric air masses affecting MWO among such synoptic conditions. Case studies of stratospheric intrusions at MWO are discussed here. We further quantify the contributions of stratosphere and photochemistry to O3 in the Northeastern U.S. using a global 3-D chemistry transport model (CTM).