Recreating observed convection-generated gravity waves from weather
radar observations via a neural network and a dynamical atmospheric
model
Abstract
Convection-generated gravity waves (CGWs) transport momentum and energy,
and this momentum is a dominant driver of global features of Earth’s
atmosphere’s general circulation (e.g. the quasi-biennial oscillation,
the pole-to-pole mesospheric circulation). As CGWs are not generally
resolved by global weather and climate models, their effects on the
circulation need to be parameterized. However, quality observations of
GWs are spatiotemporally sparse, limiting understanding and preventing
constraints on parameterizations. Convection-permitting or -resolving
simulations do generate CGWs, but validation is not possible as these
simulations cannot reproduce the forcing convection at correct times,
locations, and intensities.
Here, realistic convective
diabatic heating, learned from full-physics convection-permitting
Weather Research and Forecasting (WRF) simulations, is predicted from
weather radar observations using neural networks and a previously
developed look-up table. These heating rates are then used to force an
idealized GW-resolving dynamical model. Simulated CGWs forced in this
way did closely resemble those observed by the Atmospheric InfraRed
Sounder in the upper stratosphere. CGW drag in these validated
simulations extends 100s of kilometers away from the convective sources,
highlighting errors in current gravity wave drag parameterizations due
to the use of the ubiquitous single-column approximation. Such
validatable simulations have significant potential to be used to further
basic understanding of CGWs, improve their parameterizations physically,
and provide more restrictive constraints on tuning
\textit{with confidence}.