2006

 The micro-SDLA balloonborne diode laser spectrometer was flown twice from Bauru (22◦ S, Brazil) in February 2004 during HIBISCUS to yield in situ H2O measurements in the Upper Troposphere (UT) and Lower Stratosphere (LS) and in particular in the 5 Tropical Tropopause Layer (TTL). The overall TTL was found warmer (with a subsaturated cold point near –79◦C) and the LS moister compared to former measurements obtained in tropical oceanic conditions. The use of specific balloons with a slow descent, combined with the high-resolution of the laser sensor, allowed us to observe in situ in the UT, the TTL and the LS several thin layers correlated on H2O, CH4 , O3 , 10 temperature and PV. A component of these layers is associated with the isentropic transport into the UT- LS of extratropical stratospheric air masses. Moreover, the examination of temperature and tracer (CH4 , O3 ) profiles gives insights on the potential contribution of convective transport of H2O in the TTL

DURRY, G ; HURET N ; Hauchecorne, A ; MARECAL, V ; POMMEREAU, J P ; R L JONES ; HELD, G. . Isentropic advection and convective lifting of water vapor in the UT ? LS as observed over Brazil (22° S) in February 2004 by in situ high-resolution measurements of H2O, CH4, O3 and temperature. Atmospheric Chemistry and Physics Discussion (Online), v. 6, p. 12469-12501, 2006.