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Please use this identifier to cite or link to this item: http://hdl.handle.net/10204/5265

Title: Tropopause characteristics and variability from 11 yr of SHADOZ observations in the southern tropics and subtropics
Authors: Sivakumar, V
Bencherif, H
Begue, N
Thompson, AM
Keywords: Tropopause
Southern Hemisphere Additional Ozonesonde
Issue Date: Jul-2011
Publisher: American Meteorological Society
Citation: Sivakumar, V, Bencherif, H, Begue, N and Thompson, AM. 2011. Tropopause characteristics and variability from 11 yr of SHADOZ observations in the southern tropics and subtropics. Journal of Applied Meterology and Climatology, Vol 50(7), pp 1403-1416
Series/Report no.: Workflow request;7039
Abstract: In this paper, tropopause characteristics observed from tropical to subtropical Southern Hemisphere stations using Southern Hemisphere Additional Ozonesonde (SHADOZ) data are presented for the 11-yr period of 1998–2008. Three different definitions of tropopause—cold-point tropopause (CPT), lapse-rate tropopause (LRT), and ozone tropopause (OT)—are determined, and their variability for nine different SHADOZ sites is studied for the purpose of evaluating their usefulness as indicators of possible tropopause trends. For each station, the OT is uniquely defined by the ozone gradient and is found to be more variable than either LRT or CPT. The OT roughly coincides with the upper boundary of the region of most active convective mixing over the western Pacific Ocean and with the lower boundary of the transition region from the troposphere to the lower stratosphere that is generally referred to as the tropical tropopause layer. The monthly and year-to-year variations in the tropopause are examined, and the annual cycle in OT, the dominant signal, is described. The distance of separation of the OT from the CPT or LRT is smaller for the tropics (stations at 08–158S) than for the subtropics (158–258S). The decadal trend in tropopause heights is measured using a statistical model that accounts for natural variations expressed in El Nino–Southern Oscillation, the quasi-biennial oscillation, and the Indian Ocean dipole. The decadal trend estimation shows no statistically significant trend for the CPT and LRT in the tropics, in contrast to other studies. Adecrease in altitude for the OT is significant. In the subtropics, the CPT and LRT decline significantly, by 2240 and 2190 m (10 yr)21, respectively, but the OT increases.
Description: Copyright: 2011 American Meteorological Society
URI: http://journals.ametsoc.org/doi/abs/10.1175/2011JAMC2453.1
ISSN: 1558-8424
Appears in Collections:Climate change
Earth observation
General science, engineering & technology
Earth observation technologies

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