B`egue, NBencherif, HSivakumar, VKirgis, GMz'e, NLeclair de Bellevue, J2010-08-242010-08-242010-04B`egue, N, Bencherif, H, Sivakumar, V. 2010. Temperature variability and trend estimates at tropopause and UT-LS over a subtropical site: Reunion (20.8_ S, 55.5_ E). Atmospheric Chemistry and Physics Discussions, Vol. 10(4), pp 10113-101431680-7367www.atmos-chem-phys-discuss.net/10/10113/2010/http://hdl.handle.net/10204/4203Copyright: Author(s) 2010. This work is distributed under the Creative Commons Attribution 3.0 LicenseThis paper mainly focuses on the trends and variability of the tropopause and UT-LS temperature using radiosonde observations carried out over 16 years (January 1993 to December 2008) from a southern subtropical site, Reunion Island (20.8° S, 55.5° E), using a linear-regression fitting model. Two kinds of tropopause definitions, namely, cold point tropopause (CPT) and lapse rate tropopause (LRT) are used. In the purpose to characterize and quantify the relationship between the regional oceanic forcing and temperature at tropopause and UT-LS, we take into account the Indian Ocean Dipole (IOD) for the estimation of temperature trends. Results show that the main component is the Annual Oscillation (AO), particularly at tropopause (CPT, LRT) and in the lower stratosphere (LS) where more than 26% of the variability of temperature can be explained by AO. As a result, the influence of IOD on the variability of the temperature is at highest ratio at CPT and LS, with respectively 12.3% and 13.1%. The results show a low correlation between IOD and the temperature anomalies at tropopause (LRT, CPT) and UT-LS, in the range of 0.08–0.15, with the maximum of correlation at CPT (0.15). In addition, trend estimates at CPT and in the LS suggests that the IOD forcing contributes enhancing the rate of cooling of about 0.1 K per decade. Indeed a trend analysis reveals a cooling of about 0.90±0.40 K per decade at LS and a cooling trend of about 0.36±0.48 K per decade at CPT. The cooling trend at LS is found to be in good agreement with the others studies. These results support the assumption that the Indian Ocean may have a slight impact on temperature variability and on temperature change at CPT and in the LS over Reunion.enTemperatureTropopauseRadiosondeEarth’s atmosphereArticleB`egue, N, Bencherif, H., Sivakumar, V., Kirgis, G., Mz'e, N., & Leclair de Bellevue, J. (2010). Temperature variability and trend estimates at tropopause and UT-LS over a subtropical site: Reunion (20.8_ S, 55.5_ E). http://hdl.handle.net/10204/4203B`egue, N, H Bencherif, V Sivakumar, G Kirgis, N Mz'e, and J Leclair de Bellevue "Temperature variability and trend estimates at tropopause and UT-LS over a subtropical site: Reunion (20.8_ S, 55.5_ E)." (2010) http://hdl.handle.net/10204/4203B`egue, N, Bencherif H, Sivakumar V, Kirgis G, Mz'e N, Leclair de Bellevue J. Temperature variability and trend estimates at tropopause and UT-LS over a subtropical site: Reunion (20.8_ S, 55.5_ E). 2010; http://hdl.handle.net/10204/4203.TY - Article AU - B`egue, N AU - Bencherif, H AU - Sivakumar, V AU - Kirgis, G AU - Mz'e, N AU - Leclair de Bellevue, J AB - This paper mainly focuses on the trends and variability of the tropopause and UT-LS temperature using radiosonde observations carried out over 16 years (January 1993 to December 2008) from a southern subtropical site, Reunion Island (20.8° S, 55.5° E), using a linear-regression fitting model. Two kinds of tropopause definitions, namely, cold point tropopause (CPT) and lapse rate tropopause (LRT) are used. In the purpose to characterize and quantify the relationship between the regional oceanic forcing and temperature at tropopause and UT-LS, we take into account the Indian Ocean Dipole (IOD) for the estimation of temperature trends. Results show that the main component is the Annual Oscillation (AO), particularly at tropopause (CPT, LRT) and in the lower stratosphere (LS) where more than 26% of the variability of temperature can be explained by AO. As a result, the influence of IOD on the variability of the temperature is at highest ratio at CPT and LS, with respectively 12.3% and 13.1%. The results show a low correlation between IOD and the temperature anomalies at tropopause (LRT, CPT) and UT-LS, in the range of 0.08–0.15, with the maximum of correlation at CPT (0.15). In addition, trend estimates at CPT and in the LS suggests that the IOD forcing contributes enhancing the rate of cooling of about 0.1 K per decade. Indeed a trend analysis reveals a cooling of about 0.90±0.40 K per decade at LS and a cooling trend of about 0.36±0.48 K per decade at CPT. The cooling trend at LS is found to be in good agreement with the others studies. These results support the assumption that the Indian Ocean may have a slight impact on temperature variability and on temperature change at CPT and in the LS over Reunion. DA - 2010-04 DB - ResearchSpace DP - CSIR KW - Temperature KW - Tropopause KW - Radiosonde KW - Earth’s atmosphere LK - https://researchspace.csir.co.za PY - 2010 SM - 1680-7367 T1 - Temperature variability and trend estimates at tropopause and UT-LS over a subtropical site: Reunion (20.8_ S, 55.5_ E) TI - Temperature variability and trend estimates at tropopause and UT-LS over a subtropical site: Reunion (20.8_ S, 55.5_ E) UR - http://hdl.handle.net/10204/4203 ER -