Temperature perturbations in the troposphere - stratosphere over Thumba ( 8 . 5 ◦ N , 76 . 9 ◦ E ) during the solar eclipse 2009 / 2010

Measurements of atmospheric temperature profiles in the troposphere and lower stratosphere were made over Thumba Equatorial Rocket Launching Station (TERLS) (8.5 N, 76.9 E) during a partial solar eclipse (22 July 2009) and an annular solar eclipse (15 January 2010). It was observed that during the partial solar eclipse, the temperature decreased by 2–3 C in the vicinity of the tropopause and in the lower stratosphere the temperature increased by ∼2.6 C during the maximum phase of the partial solar eclipse. During the annular solar eclipse, a temperature reduction of ∼2 C was observed around the tropopause. This study also revealed a feature of delayed effect in the form of a very intense warming of ∼8 C at 18 km after about 4 h of the annular solar eclipse. The Cold-Point Tropopause (CPT) temperature increased slowly before the beginning of the eclipse (up to 10:00 IST) and during the maximum phase of the eclipse, the difference in CPT temperature and height was −3.5 C and ∼110 m, respectively, as that of the control day. After the four hours of the eclipse, the CPT height had decreased by ∼1.7 km and the CPT temperature increased by ∼4.6 C. This is for the first time that the diurnal variation of the tropopause has been reported during a solar eclipse day. The present study, thus, provided an opportunity to investigate the temperature perturbations in the troposphere and lower stratosphere during a partial and annular solar eclipse. The highlight of the present results are (1) cooling of the entire troposphere and lower stratosphere during the maximum phase of annular solar eclipse, (2) an intense heating of the lower stratosphere by 8 C after nearly four hours from the maximum phase of the annular eclipse, and (3) drastic variations in the diurnal evolution of the tropical tropopause characteristics. The cooling effect is attributed to the radiative response of the atmosphere to the solar eclipse, where as heatCorrespondence to: K. V. Subrahmanyam ([email protected]) ing is attributed to the dynamical response of the atmosphere to the solar eclipse. These results may have important implications in understanding the response of the atmosphere to the radiative, as well as dynamical, perturbations caused by any celestial or terrestrial disturbances.