We have extended the satellite-based ozone anomaly time series to the present (December 2012) by merging SAGE II (Stratospheric Aerosol and Gas Experiment II) with OSIRIS (Optical Spectrograph and Infrared Imager System) and correcting for the small bias (∼ 0.5%) between them, determined using their temporal overlap of 4 years. Analysis of the merged data set (1984– 2012) shows a statistically ...

5 A dynamical relationship that connects the extratropical tropopause potential tempera6 ture and the near surface distribution of equivalent potential temperature was proposed in 7 a previous study and was found to work successfully in capturing the annual cycle of the 8 extratropical tropopause in reanalyses. This study extends the diagnosis of the moisture9 tropopause relationship to an ense...

Here we present observations of the Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) of cirrus cloud and water vapour in August 1997 in the upper troposphere and lower stratosphere (UTLS). The observations indicate a considerable flux of moisture from the upper tropical troposphere into the extratropical lowermost stratosphere (LMS), resulting in the occurrence of hig...

A recent model study (Sherwood and Dessler 2001) found that dehydration of air within energetic overshooting convective cells, followed by slow lofting into the stratosphere, could account for moisture levels in the lower stratosphere and upper troposphere given realistic horizontal transports and diabatic circulations. Here, we present augmented model simulations of transport across the tropic...

During boreal summer, much of the water vapor and CO entering the global tropical stratosphere is transported over the Asian monsoon/Tibetan Plateau (TP) region. Studies have suggested that most of this transport is carried out either by tropical convection over the South Asian monsoon region or by extratropical convection over southern China. By using measurements from the newly available Nati...

Optically thin cirrus near the tropical tropopause regulate the humidity of air entering the stratosphere, which in turn has a strong influence on the Earth's radiation budget and climate. Recent high-altitude, unmanned aircraft measurements provide evidence for two distinct classes of cirrus formed in the tropical tropopause region: (i) vertically extensive cirrus with low ice number concentra...

In an earlier study of troposphere-to-stratosphere transport (TST) via the tropical tropopause layer (TTL), we found that the vast majority of air parcels undergoing TST from the base of the TTL enter the extratropical lowermost stratosphere quasi-horizontally and show little or no regional preference with regards to origin in the TTL or entry into the stratosphere. We have since repeated the t...