Large-scale and Climate Dynamics

The Large-scale and Climate Dynamics program at Davis examines basic fluid dynamics and short-term climatic processes. Some of the research combines dynamics, thermodynamics, radiation and synoptic meteorology. The phenomena studied range in scale from a single midlatitude frontal cyclone up to global circulations. Some students are investigating fluid dynamic instabilities with linear and nonlinear models of frontal systems. Large-scale tropical circulations and their midlatitude interactions are incorporated into this program, as well. Most students are using various computer models to simulate atmospheric circulations. Some students are also studying observational data with advanced statistical techniques.

Select a faculty member's name below to visit their web page.

Richard Grotjahn

has research projects in large scale atmospheric climate dynamics. He works on the synoptic to global length scales. Examples of past projects include the following. (1) Fluid dynamical instability of midlatitude flows using such tools as: large linear eigenvalue problems, linear initial value problems, and nonlinear initial value problems in Cartesian and spherical geometry. Our approach is to ground our theoretical studies with targeted observational studies and vice-versa. (2) Forecasting work includes model verification and constructing historical analogs from past extraordinary weather events. (See the forecast analogs website for significant large-scale patterns associated with such regional events as: severe freezes, heat waves, and heavy rain.) These studies employ various statistical analysis tools. Current research includes the following projects: (3) studies of what factors, both local and remote, maintain the subtropical highs, (4) research following up on Dr. Grotjahn’s book on the general circulation, (5) studies of what model defects are causing specific Arctic region surface climate biases in climate models, (6) study of the origin of air reaching California (relevant to air quality compliance), and (7) application of analog techniques to identify the climatology of extraordinary weather in a climate undergoing global change.

Terrence Nathan's

research is fundamental in nature and focuses on identifying and understanding the physical and dynamical mechanisms that govern the spatial and temporal evolution of large-scale atmospheric circulation systems. Professor Nathan's research involves combining observations with advanced mathematical techniques to study the following: tropical-midlatitude interactions during El Niño and La Niña flow regimes; stability of geophysical fluid flows; nonlinear dynamics of atmospheric circulations; and interactions among radiation, ozone and dynamics in the stratosphere. Additional research includes using proxy data (e.g. dendroclimatic reconstruction and historical records) to examine the impacts of meteorological events on exploration, including the Lewis and Clark expedition.

Ruth Reck's

primary field of research is global climate change. This includes the processes defining the global energy and moisture balance, and the related impacts on the earth's climate and ecosystem. Her interests include atmospheric physics and chemistry and the relationship to the observed behavior of the atmosphere.

Bryan Weare

studies atmospheric processes associated with such varied tropical short-term climate variations as El Niño events, the 40-50 day wind oscillation and the possible impact of global climate change. This research is aimed at understanding how climate is affected by diabatic heating at the bottom, top and within the atmosphere through the use of both models and observations. The data include ship derived observations from which the heat budget at the ocean surface may be derived, together with satellite estimates of the radiation budget at the top of the atmosphere. The goal of Professor Weare is to use sophisticated statistical analysis techniques to diagnose how the pattern of climate changes relates to the basic forcing terms in both models and the real atmosphere. A major component of his research is to understand how cloudiness in the tropics interacts with El Niño and climate change. Professor Weare applies modern statistical techniques such as autoregressive spectra, regular and complex empirical orthogonal functions and linear and nonlinear multiple regressions in his research work. Other areas of interest of Professor Weare include improving statistical techniques for analysis and prediction and estimating the impacts of potential changes in climate on agriculture.