Dynamics and Impacts of Mesoscale Gravity Waves in Baroclinic Jet-Front Systems

  • Zhang, Fuqing (PI)

Project: Research project

Project Details

Description

Intellectual Merit: Gravity waves are ubiquitous in the atmosphere and play a fundamental role in a wide variety of atmospheric processes that have important implications to tropospheric weather, stratospheric dynamics, ozone chemistry and general circulation. They can transfer significant amounts of energy and momentum, initiate and organize convection, and produce atmospheric turbulence. The momentum transport and deposition by gravity waves have significant impacts on the general circulation of the atmosphere. A better knowledge of these processes demands a complete understanding of the mechanisms by which the gravity waves are generated, together with their characteristics, distribution and variability. While past observational studies have repeatedly demonstrated that many of the mesoscale gravity waves with horizontal wavelength of 50-500 km are strongly associated with the midlatitude baroclinic jet-front systems, the exact generation mechanisms of these waves remain uncertain. Building on the progress made using dry dynamics, the ultimate goal of this research is to understand the dynamics and impacts of the mesoscale gravity waves generated by the tropospheric baroclinic jet-front systems and their interaction with moist convection. This study will progressively approach the problem by using high-resolution dry and moist idealized simulations of baroclinic waves, real-case hemispheric modeling and satellite observations. Major objectives include: i) expanding the investigation of gravity waves in the idealized simulations of dry dynamics to further track the wave source origins and spatial/temporal variations through the use of the ray tracing technique and to further differentiate the roles of balance vs. imbalance in the wave generation through direct calculations of wave forcing and response; ii) performing high-resolution simulations of idealized moist baroclinic waves, investigating the characteristics and dynamics of the gravity waves simulated therein and exploring the interactions between gravity waves and convection; and iii) extending the use of mesoscale models to a quasi-hemispheric domain to simulate gravity waves associated with midlatitude baroclinic jet-front systems for an entire winter season, comparing the model results with satellite observations and idealized simulations, and qualitatively assessing the momentum and energy fluxes and their impacts.

Broader Impacts: Better understanding of mesoscale gravity waves and their interaction with moist processes may lead to better understanding of the dynamics and improved forecasts of convective triggers and modulation as well as the associated severe weather. Better understanding of flow imbalance and mesoscale gravity waves may provide guidance on mesoscale data assimilation and mesoscale predictability. Better understanding of gravity wave processes may also lead to better parameterization of the energy and momentum transport between the troposphere and stratosphere by non-topographic and non-convective mesoscale gravity waves.

StatusFinished
Effective start/end date10/1/089/30/11

Funding

  • National Science Foundation: $250,537.00

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