Characteristics of temperature inversion from radiosonde measurements in the Western Ghats region

The characteristics of temperature inversion (TI) are believed to be dependent on topographical features and synoptic regime. Western Ghats (WGs) mountains located in the west coast of India have a complex topography, and the TI features for this region remain unknown due to the complexity and non-availability of observational datasets. This study investigates TI characteristics in the troposphere using high-resolution radiosonde data (2012-2015). The radiosonde measurements are collected at Mahabaleshwar (17.92 degrees N, 73.6 degrees E, similar to 1.4 km above mean sea level, AMSL), a high-altitude site in the WGs. The characteristics of TI in terms of height, depth, and strength (i.e., temperature difference between base and top of the inversion layer) are studied. The results showed that TI occurs in all seasons, however, their frequency differs. Winter (Dec.-Feb.) shows the maximum number of inversions followed by pre-monsoon (Mar.-May), post-monsoon (Oct.-Nov.), and monsoon (Jun.-Sep.). In winter, the depth of inversion is higher; however, the inversion strength is weaker as compared to other seasons. The TI strength is always below 5 K. Apart from surface-based inversions, elevated and uppertropospheric inversions are also observed. Vertical and horizontal wind shear profiles along with ERA-5 data were analyzed to examine the plausible mechanism for TI to occur.

Automated summary

Using high-resolution radiosonde data from Mahabaleshwar, this study investigates characteristics of temperature inversion (TI) in the troposphere. The results show that TI occurs in all seasons, with winter having the highest frequency of inversions. The depth of inversion is higher in winter, but the strength is weaker compared to other seasons, always below 5 K. In addition to surface-based inversions, elevated and upper-tropospheric inversions were also observed.