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An integrated campaign "Suryagrahan‐2019" with multi‐institutional support was conducted by launching a series of radiosondes/ozonesondes over 6‐different locations in India along with the operation of ST/MST radars and launching of RH‐200 rockets during the annular solar eclipse of 26 December 2019. We present the eclipse‐induced changes in the thermal structure, dynamics and trace gases in the lower and middle atmosphere. One of the novel findings is the formation of three step‐like isothermal structures in the lower stratosphere with a layer height of 1.4, 2.5, and 4 km, which is attributed to the adiabatic compression and expansion of the air parcel. These structures have both warming and cooling effect of the order of ±6 K. A significant increase of ozone by 20% in post‐eclipse scenario between 29 and 32 km is observed over Cochin. Strong downdrafts of ∼−0.25 m s−1 are observed between 12 and 16 km during the eclipse event, which is attributed to the atmospheric compression due to the sudden cooling during the eclipse event. Due to the changes in thermal structure, the atmospheric circulation changes are observed in the meridional wind. During the maximum obscuration, there is a sudden decrease in near‐surface and boundary layer ozone by 12–15 ppbv. The present study reiterates that the eclipse‐induced perturbations depend on the local time of the eclipse event and place of observations. It is envisaged that the results discussed in the study will improve our understanding of the eclipse induced perturbations in the Earth's atmosphere. Plain Language Summary: Solar eclipse provides a well‐characterized reduction in solar radiation for a few hours, which provides a natural laboratory to understand and quantify the atmosphere's response to the abrupt cut‐off in the solar radiation. In this context, an integrated campaign "Suryagrahan‐2019" was conducted in India by launching a series of radiosonde/ozonesonde along with the operation of ST/MST radars during the annular solar eclipse event occurred on 26 December 2019. Several isothermal structures, followed by warming and cooling effect in the different stratospheric heights were observed. Alter in the ozone profile, especially in the lower stratosphere was one of the causative mechanism behind the modulations of thermal structure. Adiabatic compression and expansion of the air parcel in the lower stratosphere are explained in term of solar eclipse induced effects. Change in meridional circulation due to sudden solar cut‐off is reported. Key Points: Solar eclipse induced isothermal structure and adiabatic compression and expansion in the lower stratosphere were observedIncrease in ozone in the lower stratosphere during post‐eclipse scenario, whereas spontaneous decrease of surface ozone were reportedChange in meridional circulation due to sudden cut‐off of solar radiation [ABSTRACT FROM AUTHOR]

Altitude structure of turbulence in the troposphere and lower stratosphere (TLS) over the Indian peninsula is delineated using radiosonde observations carried out from six stations (August 2013 to December 2017) as part of the Tropical Tropopause Dynamics (TTD) Campaign under the GPS Aided Radiosonde Network Experiment for Troposphere–stratosphere Studies (GARNETS) program. Thorpe analysis applied to the potential temperature profiles, taking into account the impact of atmospheric moisture and instrumental noise, is used to estimate the turbulence parameters. This study shows that while the occurrence of turbulence is high in the lower (0–2 km) and upper (10–15 km) troposphere, the region 3–8 km is relatively devoid of turbulence at all the six stations. In general, ~60% of the Thorpe scale (L T) values in the troposphere are less than 250 m at all the stations, except at Cochin where it extends up to 400 m. Though the altitudinal structure of turbulence shows large variability from station-to-station, it does not show any systematic latitudinal pattern. This study also shows that the Thorpe method appears to be good in identifying convectively induced turbulence than the dynamically (shear) induced turbulence. In the lower troposphere, the turbulence is due to both convective and dynamic instability at all the stations. While turbulence in the altitude region between 10 and 15 km is mainly due to convective instability at Coimbatore, Gadanki and Goa and due to dynamic instability at Cochin, both these instabilities contribute significantly to the generation of turbulence at Trivandrum and Hyderabad. Occurrence of convective instability (turbulence) under clear-air conditions in the upper troposphere, suggests wave breaking as a mechanism. • Altitude structure of turbulence studied over six locations of Indian peninsula. • Occurrence of turbulence is high in the lower and upper troposphere. • There is no systematic station to station variations in the turbulent structure. • Convective and dynamical instabilities are responsible for the turbulence generation. • Thorpe method appears to be good in identifying convectively induced turbulence. [ABSTRACT FROM AUTHOR]