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Planetary‐scale tropopause folds in the southern subtropics
Author(s) -
Baray J. L.,
Daniel V.,
Ancellet G.,
Legras B.
Publication year - 2000
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1999gl010788
Subject(s) - tropopause , hadley cell , troposphere , climatology , potential vorticity , geology , subtropics , atmospheric sciences , zonal and meridional , equator , longitude , atmospheric circulation , latitude , general circulation model , vorticity , oceanography , climate change , meteorology , vortex , geography , geodesy , fishery , biology
Daily measurements of tropospheric ozone at La Reunion Island (55 E, 21 S) in July 1998 show that ozone layers are quasi‐permanent in the troposphere between 6 and 10 km with values reaching 80 to 100 ppbv. Meridional cross sections of potential vorticity reveal that these layers are related to tropopause folds beneath the subtropical jet. Folding is persistent and extends over a considerable longitude range from mid‐Atlantic to mid‐Pacific. We suggest that this structure is due to the convergent flow associated to the descent branch of the Hadley circulation during austral winter.