Ozone Deple*on Events in the Ross Island Region, Antarc*ca and the Associated Meteorological Condi*ons 1,2Mark W. Seefeldt ([email protected]), 1Allison M. Burg, 3Lars E. Kalnajs, and MaMhew A. Lazzara 1Department of Engineering – Physics Systems, Providence College, Providence, RI 2CIRES / 3LASP – University of Colorado at Boulder, Boulder, CO Introduc*on: Ozone Depleon Events: Case Study – September 2004: Naturally occurring near-surface • It is cri5cal to dis5nguish ozone deple5on events have been between anthropogenic ozone observed during the austral spring deple5on and ODEs Anthropogenic Ozone Deple5on Events (ODEs) in the Ross Island region, • Anthropogenic ozone deple5on Ozone Deple5on Antarc5ca. The ozone deple5on is observed year round events (ODE) require sunlight and a • ODEs are primarily observed • An ozone depleted air source of bromine. It is s5ll unclear during the austral spring mass is advected into how the reac5ve bromine is (August to November) Fig. 1: Near-surface ozone Fig. 4: Near-surface O3 concentraon the region released from the sea salt. There is concentra*on for McMurdo Sta*on • Overall, the iden5ficaon of for McMurdo Sta*on for August 2005. • The recovery of the a possible meteorology connec5on. (Arrival Heights) for October 2003. ODEs, based solely on ozone observaons is subJec5ve 164°E 166°E 168°E 170°E ozone begins with the Cape Biird Five near-surface ozone *# change in direc5on Mount Bird Lewis Bay sensors were installed at Types of ODEs: from the NW Marblle Poiint *# Ross Island S ' 0 Mount Erebus 3 ° 7 7 Mount Terror S ' Cape Royds 0 3 automac weather staon ° 7 • 7 The type of ODE can be classified based on the mechanism or The wind shi^ing to the NE results in another drop in ozone y Ozone Instrument lle Va r McMurdo Sound lo Network a y T r Windless Bight ie Windless Bight University of Colorado (AWS) sites during the c *# la Ross Island & Vicinity G process that is resul5ng in the ozone loss. ar rr Fe Case Study – October 2005: McMurdo Station Imagery from Landsat Image Mosaic of Antarctica (LIMA) 2011-12 field season. The Placenames derived from • s Transport-Controlled Events: A rapid onset with significant l SCAR Gazeteer il Ross Ice Shelf H Cartography by Claire Porter n and Cole Kelleher, S ° 8 o Polar Geospatial Center 7 t S n ° 8 WGS84 Antarctic Polar 7 sensors are operang year e Brown Peninsula D Stereographic Projection ozone loss, o^en occurs with wind speed / direc5on changes Latitude of True Scale: -71° Central Meridian: 166° r e ci White Island Lines of longitude indicate la true north G z round with a focus on the t li Lorne • Black Island t *# Horizontal advec5on of ozone depleted air mass t e o K Mount Discovery ozone deple5on events. An M • i Changes in boundary layer depth n na B luff S ' 0 3 ° 8 7 S # ' * 0 3 ° 8 7 understanding of the Miinna Blluffff • Chemically-Controlled ODE: More gradual and not as intense 164°E 166°E 168°E 170°E 172°E meteorology of the region Fig. 2: Locaon map of the Ross Island region • The ozone deple5on chemistry occurring locally feautring AWS sites with co-located ozone will assist in establishing the • Can be amplified with increased release of bromine • Ozone depleted air is sensors highlighted. source and evolu5on of An analysis of the associated meteorology can provide a beZer advected into the area ozone depleted air masses. understanding of the type of ODE and the associated • Possible changes in Meanwhile, a study of the ozone mechanisms to the ozone loss. In the following cases a nearby boundary layer depth concentraon from nearby McMurdo AWS is used for the meteorological study. result in differences in Staon (Arrival Heights) provides a Case Study – August 2011: the presence of ozone good characterizaon of the ozone depleted and non- climatology to establish the context depleted air for the observaons from the ozone sensor network. • During the summer months the O3 concentraon is around 10-20 ppb. • During the fall months there is a • There is a warming prior steady recovery in O3 to the onset of the ODE concentraon. • The winds are light prior • The O3 levels off at approximately to the ODE and then 36 ppb. increase in speed • The same general paern is • The wind is from the NW Acknowledgments: observed every year. prior to the onset, and Support for Seefeldt, Burg and Kalnajs was provided for by the Overall, the locaon (above the ice then shi^s to the S Naonal Science Foundaon: ANT-1043266 surface, near McMurdo, etc.) has • The associated AWS observaons indicate that this ODE is a The installaon, operaon, and processing of the automac limitaons in understanding ODEs. transport related event weather staons observaons are supported by the Naonal Fig. 3: Near-surface ozone concentra*on for McMurdo Science Foundaon: ANT-0838834 Sta*on (Arrival Heights) for Jan., Apr., and July 2010. .