Inertia gravity wave characteristics and associated fluxes observed using five years of radiosonde measurements over a tropical station

In the present study, characteristics of inertia gravity waves (IGWs), associated momentum and heat fluxes, and their source mechanisms have been studied using five years (2006–2011) of high resolution radiosonde observations collected from the tropical station, Gadanki (13.5°N, 79.2°E), India. The deduced horizontal wavelengths are of the order of a few 1000s km in the troposphere and stratosphere in contrast to those low horizontal wavelengths reported earlier from this location. The estimated horizontal wavelengths match well with those reported very recently using satellite (HIRDLS and SABER) measurements. Clear link between the fluxes and background wind are noticed with enhanced values during the westward phase of zonal wind. Although two sources for the generation of IGWs namely strong convection and wind shears coexist during monsoon season, wind shear is found to be mainly responsible.

► Characteristics of IGWs, associated momentum and heat fluxes, and their source mechanisms are reported. ► The deduced horizontal wavelengths are high in contrast to those reported earlier. ► The estimated horizontal wavelengths match well with those reported using satellite measurements. ► Wind shear is found to be mainly responsible for the generation of IGWs over this region.