Abstract
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.