The extreme variability of the cold point tropopause temperature (TCPT) and height (HCPT) are examined over a tropical station, Gadanki (13.45N, 79.2E) using high-resolution radiosonde data during the period 2006-2014. The extreme variabilities such as the coldest (warmest) tropopause is defined if TCPT is lesser (greater) than the lower (upper) limit of its two-sigma level whereas the highest (lowest) tropopause is defined as the HCPTis greater (lesser) than the lower (upper) limit of its two-sigma level. In total 161 extreme cases such as the coldest (52) and warmest (30) TCPT and the highest (57) and lowest (22) HCPT are observed. The coldest (187.2±1.60 K, 17.3±0.52 km), warmest (194.2±1.78 K, 16.9±0.89 km), lowest (191.7±1.78 K, 18.2±0.55 km) and highest (191.8±2.11 K, 16.2±0.38 km) occurs without preference of season. These extreme tropopause cases occur independently. Thermal structure of the coldest tropopause cases reveals that they are often sharper whereas the warmest, highest and lowest tropopause is broader. Water vapor and ozone concentrations are found to be high for the warmest tropopause and low for the coldest tropopause. Under the shallow convection, extreme temperature profiles, in general, show prominent warming between 8-14 km while anomalous cooling (warming) just below (above) the CPT. The occurrence of the tropical cyclones, cirrus clouds and equatorial wave propagation are the possible candidates for the occurrence of the extreme tropopauses.

This paper presents the first quantitative relationship between the cold point tropopause (CPT) and tropical easterly jet (TEJ) using radiosonde observations over Gadanki (13.45oN, 79.2oE) during the Indian summer monsoon season 2006–2014. CPT and TEJ peak altitudes (H_CPT and H_TEJ) show amalgams of two categories of variability on day to day scale. In category1 H_TEJ occurs close to H_CPT and they show in phase variation. While in category2 H_TEJ occurs far apart from H_CPT and they do not show any relationship. For category1 H_CPT and H_TEJ are strongly correlated (0.70) as well as H_CPT and T_CPT (CPT temperature) are moderately anticorrelated (-0.55) significant at 95% confidence level indicating the dominance of adiabatic processes. Whereas in category2 H_CPT and T_CPT are not significantly anticorrelated. Thus, when TEJ and CPT are close to each other it may serve as an indicator for the prevalence of synoptic-scale effect.