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A significant change in temperature in the tropopause and stratosphere, from pole to the tropics, was observed during a major Sudden Stratospheric Warming (SSW) occurring in January 2009. The SSW event strongly modified the pattern of polar and tropical stratospheric circulation. After termination of SSW, a new pattern emerged that prevailed for ~ 2–3 months. After SSW, a clear descending cold phase completely replaced the warm phase in the polar regions. During the warm phase, temperature increased to ~ 40 °C in stratosphere (> 30 km altitude) in the polar region (80°N–90°N), then it dropped down to − 80 °C during the cold phase. Interestingly, new warm anomalies appeared over the tropical region during the cold phase at polar regions. Possible implications of these unusually warm and cold phases are demonstrated in this study. These phases altered significantly the cold point tropopause temperature and its height. SSW also affected the tropical atmospheric stability. Cross equatorial response (from northern to southern hemisphere) up to 40°S was observed in the form of persisting anomalies as a consequence of the SSW event. [ABSTRACT FROM AUTHOR]

The effect of quasi-biennial oscillation (QBO) on the temperature of cold point tropopause (T-CPT) and its height (H-CPT) is being investigated using radio occultation measurements by COSMIC/FORMOSAT-3. Observations comprising of 935,863 numbers of occultations have been used to study the zonal mean seasonal variability in T-CPT and H-CPT from January 2007 to December 2011. Results are shown over 30°N–30°S geographic latitudes. In general, T-CPT is found to be the coldest in February and the warmest in August. H-CPT attains maximum height during December–February and minimum during July–August. Interestingly, H-CPT shows maxima at off-equator region (around 20°N or 20°S) during all the seasons in both hemispheres. H-CPT at off-equatorial region, in reference to the equatorial region, is slightly higher (~1.0km) during winter as compared to monsoon season (~0.5km) in Northern Hemisphere (NH). Inter-annual variation in T-CPT and H-CPT found to be clearly influenced by the QBO. Westerly (easterly) phase generates warm (cold) T-CPT, which consequently results a decrease (increase) in H-CPT. It is concluded that QBO induces the changes in T-CPT by as much as 2°C and in H-CPT by 0.5km. [ABSTRACT FROM AUTHOR]