New approach to incorporating the impacts of non-hydrostatic perturbations in atmospheric models

Fa-Bo Zhang,Bin Wang,Li-Juan Li

doi:10.1080/16742834.2017.1348191

Abstract

AbstractHow to properly consider the impacts of non-hydrostatic perturbations is one of the challenging issues in developing non-hydrostatic dynamics solvers (NHDSs) for high-resolution atmospheric models. To overcome the drawbacks of current approaches to tackling this issue, this study analyzed the differences between hydrostatic dynamics solvers (HDSs) and their non-hydrostatic counterparts. The analysis then motivated a flexible approach to adjusting existing hydrostatic atmospheric models, especially those adopted in climate simulations for the impacts of non-hydrostatic perturbations. In this approach, the impacts of non-hydrostatic perturbations, reflecting the differences between HDSs and NHDSs, were encapsulated into a single term in the vertical momentum equation for the atmosphere. At each time step, this term was estimated by a separate sub-model, and then it was used to adjust the dynamics of the atmosphere. The adjustment was optional, and could be turned on and off flexibly by utilizing dif...

Highlights

With the great advances achieved in computer technology, there is a trend in the atmospheric modeling community toward developing high-resolution non-hydrostatic atmospheric models for climate simulations (Hall 2013)
Current approaches to handling their impacts in non-hydrostatic dynamics solvers (NHDSs) for high-resolution atmospheric models are very time- consuming and too complicated to be applied to existing hydrostatic atmospheric models, especially those for climate simulations
To investigate the impacts of non- hydrostatic perturbations, this study analyzed the differences between hydrostatic dynamics solvers (HDSs) and NHDSs using the Weather Research and Forecasting (WRF) model as an example

Summary

Introduction

With the great advances achieved in computer technology, there is a trend in the atmospheric modeling community toward developing high-resolution non-hydrostatic atmospheric models for climate simulations (Hall 2013). One of the challenging problems encountered in developing these models is to incorporate the non-hydrostatic features of the atmosphere in an appropriate manner in their dynamics solvers, which are responsible for numerically resolving the dynamics of the atmosphere This problem is typically solved by the following approaches (Peng and Li 2010): (1) All Explicit (Clark 1977); (2) Horizontally Explicit Vertically Implicit (Klemp and Wilhelmson 1978); (3) Horizontally Implicit Vertically Implicit (Tapp and White 1976); and (4) Semi Implicit Semi Lagrangian (Erbes 1993). They are rather complicated, and it is difficult to apply these approaches to existing hydrostatic models to handle the impacts of non-hydrostatic perturbations

Methods

Results

Conclusion