Gravitational tidal waves in Titan's upper atmosphere

Tidal waves driven by Titan's orbital eccentricity through the time-dependent component of Saturn's gravitational potential attain nonlinear, saturation amplitudes (|T′|>10 K|T′|>10 K, |u′|>20 ms−1, and |w′|>5 cms−1) in the upper atmosphere (⩾500 km) due to the approximate exponential growth as the inverse square root of pressure. The gravitational tides, with vertical wavelengths of ∼100–150 km above 500 km altitude, carry energy fluxes sufficient in magnitude to affect the energy balance of the upper atmosphere with heating rates ⩾10−9 ergcm−3s−1 in the altitude range of 500–900 km.