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Structural diagnostics of the tropopause inversion layer and its evolution
Author(s) -
Gettelman A.,
Wang T.
Publication year - 2015
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2014jd021846
Subject(s) - tropopause , extratropical cyclone , stratosphere , climatology , troposphere , subtropics , middle latitudes , atmospheric sciences , latitude , southern hemisphere , inversion (geology) , environmental science , geology , geodesy , paleontology , structural basin , fishery , biology
The Tropopause Inversion Layer (TIL) is marked by a peak in static stability directly above the tropopause. The TIL is quantitatively defined with new diagnostics using Global Positioning System Radio Occultation temperature soundings and reanalysis data. A climatology of the TIL is developed from reanalysis data (1980–2011) using diagnostics for the position, depth, and strength of the TIL based on the TIL peak in static stability. TIL diagnostics have defined relationships to the synoptic situation in the Upper Troposphere and Lower Stratosphere. The TIL is present nearly all the time. The TIL becomes hard to define in the subtropics where tropical air overlies midlatitude air, in a region of complex static stability profiles. The mean position of the subtropical TIL gradient is sharp and is co‐located with the subtropical tropopause break. Over the period 1980–2011 the TIL depth below the tropopause has decreased by 5% per decade and increased above the tropical tropopause by a similar percentage. Furthermore, the latitude of the abrupt change in the TIL from tropical to extratropical in the lower stratosphere appears to have shifted poleward in each hemisphere by ∼1° latitude per decade, depending on the diagnostic examined. Reanalysis trends should be treated with caution.