GFDL - Geophysical Fluid Dynamics Laboratory

Stephen T. Garner

Research interests

Mesoscale phenomena in the troposphere generally have an immediate connection to heat, moisture and momentum fluxes at the earth’s surface. I have concentrated on mesoscale topographic disturbances and moist convection, especially the extreme cases that significantly alter the larger environment.

For example, in the first category, I have looked at blocking by anisotropic terrain, especially in a baroclinic atmosphere . In the second category, I have studied self-organizing convection such as squall lines and tropical cyclones. Permanent alteration of the larger environment is a big complication for numerical modeling, because it requires resolving many scales of motion simultaneously.

At larger time and space scales, I have studied the lifecycles of unstable baroclinic waves in order to understand the equilibration process at different zonal scales and subject to different physical processes.

I have experimented with a new approach to parameterizing mountain-wave drag in large-scale numerical models. The procedure is based on the theory of linear, stationary waves but includes a nonlinear component. The effect of background rotation and any alteration of the wave environment must be resolved by the model.

I have helped develop a compressible, nonhydrostatic, regional atmospheric model within GFDL’s Flexible Modeling System. The model has been used extensively for tropical-cyclone research, both at the basin scale and in smaller-scale idealized configurations. It has also been used to identify problems with coupling to a land-surface model.  Going forward, the regional model will provide context for the transition to a unified dynamical core for global and regional modeling.

AOS 571: Introduction to Geophysical Fluid Dynamics

Course notes:

Chapter 1: Transport and mixing
Chapter 2: Conservation of momentum,  heat and energy
Chapter 3: Scaling principles and filtered models
Chapter 4: Circulation and vorticity
Chapter 5: Relation between flow and mass fields
Chapter 6: Barotropic Dynamics
Chapter 7: Baroclinic Dynamics
Midterm Test

Recent publications:Mouse_user

Garner, S.T., I.M. Held, T.R. Knutson and J.J. Sirutis, 2009:  The roles of wind shear and thermal stratification in past and projected changes of Atlantic tropical-cyclone activity. J. Climate, 22, 4723-4734.

Garner, S.T., D.M.W. Frierson, I.M. Held, O. Pauluis and G.K. Vallis, 2007: Resolving convection in a global hypohydrostatic model. J. Atmos. Sci., 64, 2061-2075.

Philips, V. T. J., L. J. Donner, and S. T. Garner, 2007: Nucleation processes in deep convection simulated by a cloud-system-resolving model with double moment bulk microphysics. J. Atmos. Sci., 64, 738-761.

Knutson, T.R., J.J. Sirutis, S.T. Garner, I.M. Held and R.E. Tuleya, 2007: Simulation of the recent multi-decadal increase of Atlantic hurricane activity using an 18-km grid regional modelBull. of the Am. Meteor. Soc., 88(10), 1549-1565.

Pauluis, O., D.M.W. Frierson, S.T. Garner, I.M. Held and G.K. Vallis, 2006: The hypohydrostatic rescaling and its impacts on atmospheric convection. Theoretical and Comp. Fluid Dyn., 20, 485-499.

Pauluis, O,. and S.T. Garner, 2006: Sensitivity of radiative-convective equilibrium simulations to horizontal resolution. J. Atmos Sci., 63, 1910-1923.

Garner, S.T., 2005: A topographic drag closure built on an analytical base flux. J. Atmos. Sci., 62, 2302-2315.

Arbic, B.K., S.T. Garner, R.W. Hallberg and H.L. Simmons. 2004: The accuracy of surface elevations in forward global barotropic and baroclinic tide models. Deep-sea Res. II, 51, 3069-3101.

Schneider, T., I.M. Held, and S.T. Garner, 2003: Boundary effects in potential vorticity dynamics. J. Atmos. Sci., 60, 1024-1040.

Garner, S.T., 1999: Blocking and frontogenesis by two-dimensional terrain in baroclinic flow. Part I: Numerical experiments. J. Atmos. Sci., 56, 1495-1508.

Garner, S.T., 1999: Blocking and frontogenesis by two-dimensional terrain in baroclinic flow. Part II: Analysis of flow stagnation mechanisms. J. Atmos. Sci., 56, 1509-1523.

Balasubramanian, G., and S.T. Garner, 1997: The role of momentum fluxes in shaping the lifecycle of a baroclinic wave. J. Atmos. Sci., 54, 510-533.

Balasubramanian, G., and S.T. Garner, 1997: The equilibration of short baroclinic waves. J. Atmos. Sci, 54, 2850-2871.

Garner, S.T., 1995: Permanent and transient upstream effects in nonlinear stratified flow over a ridge. J. Atmos. Sci., 52, 227-246.

Held, I.M., R.T. Pierrehumbert, S.T. Garner, and K.L. Swanson, 1995: Surface quasigeostrophic dynamics. J. Fluid Mech., 282, 1-20.

Garner, S.T., I.M. Held and N.Nakamura, 1992: Nonlinear equilibration of two-dimensional Eady waves: A new perspective. J. Atmos. Sci., 50, 1984-1996.

Garner, S.T., and A.J. Thorpe, 1992: The development of organized convection in a simplified squall-line model. Q. J. R. Meteor. Soc., 118, 101-124.