Steady Source Gravity Wave Parameterizations and the Observed Momentum Flux Intermittency

Abstract Observational estimates of gravity wave momentum fluxes obtained from analyses of super‐pressure balloon tracks show an approximate log normal distribution in space and time. One study has suggested that a non‐orographic gravity wave parameterization with a steady source could reproduce this distribution through variability in the background wind, which “dynamically filters” the source spectrum. We use an implementation of a simple steady source gravity wave parameterization to show that this observed distribution is not reproduced, the most prominent departure from it being a large negative skew. We perform a crude tuning of the scheme's parameters to show that the discrepancy in the distribution cannot be corrected. We observe that at higher levels, parameterized fluxes are still skewed but less so. We suggest that dynamical filtering alone cannot introduce enough variability to obtain fluxes that are log normally distributed.