July 7, 2017, 1:00 pm - 2:00 pm

July 7, 1:00 pm - 2:00 pm

LIDAR observations of extreme gravity wave events in the middle atmosphere

Bernd Kaifler (German Aerospace Center)

Atmospheric gravity waves play a crucial role in the vertical coupling between the troposphere and the middle atmosphere, and are the main driver of the global residual circulation connecting both hemispheres. With horizontal wavelengths ranging from few thousands of kilometers down to few kilometers, it is still impossible to resolve the entire wave spectrum in state of the art climate chemistry models and wave effects need to be parametrized. In 2014 and 2015 two large field experiments with the goal to study atmospheric gravity waves took place above New Zealand and northern Scandinavia. LIDAR temperature observations show that propagation of mountain waves to mesospheric altitudes occurs mainly under conditions of weak to moderate forcing and sufficiently strong winds in the stratosphere. Extreme wave events resulted in temperature disturbances of more than 30 K amplitude and vertical gradients exceeding +80 K/km. This presentation aims to shed light on the nature of these extreme events and discusses their importance for the momentum budget in the middle atmosphere.