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Analysis of the Ozone Reduction Event Over the Southern Tip of South America in November 2009
Author(s) -
Akiyoshi Hideharu,
Kadowaki Masanao,
Nakamura Haruna,
Sugita Takafumi,
Hirooka Toshihiko,
Harada Yayoi,
Mizuno Akira
Publication year - 2018
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2017jd028096
Subject(s) - stratosphere , geopotential height , troposphere , polar vortex , anomaly (physics) , climatology , southern hemisphere , atmospheric sciences , northern hemisphere , environmental science , ozone , geology , geography , meteorology , physics , precipitation , condensed matter physics
A reduction of the total ozone over the southern tip of South America lasting 3 weeks occurred in November 2009. Analyses of the ERA‐Interim reanalysis data and the total ozone observed by the Ozone Monitoring Instrument indicate that the total ozone reduction event was caused by a migration of the polar vortex toward the South American continent at the time of the vortex breakup. The vortex migration is associated with an enhanced wave flux from the troposphere at 120–150°W and 50–60°S to the west of the South American continent to the stratosphere over the southern part of the continent, which led to a large negative geopotential height anomaly in the lower stratosphere. In November, a blocking event was diagnosed from the 500‐hPa geopotential height over the west of the South American continent. These results suggest a relation between the long‐lasting reduction of the total ozone over the southern tip of South America and the blocking phenomenon in the troposphere of the Southern Hemisphere through wave propagation from the blocking region in 2009. Analysis of the total ozone anomaly for 50–60°S and 65–75°W over the southern tip of South America in November for 1979–2015 indicates that the negative ozone anomaly in November 2009 was one of the largest anomalies in this 37‐year period and was associated with the large negative geopotential height anomaly in the lower stratosphere. Analyses of dynamical fields were also conducted for other years with large geopotential height anomalies.