The Effect of Different Implementations of the Weak Temperature Gradient Approximation in Cloud Resolving Models

Abstract

AbstractThe Weak Temperature Gradient (WTG) approximation is a popular method used to couple convection in limited‐area domain simulations with large‐scale dynamics. However, several different schemes have been created to implement this approximation, and these different WTG schemes show a wide range of different results in an idealized framework. Our investigation shows that different model behavior is caused by the treatment of the different baroclinic modes by the different WTG schemes. More specifically, we hypothesize that the relative strengths of the baroclinic modes plays a large role in these differences, and show that modifying these schemes such that they treat the baroclinic modes in a similar manner accounts for many of the significant differences observed.