Climate and Climate Change
The climate system is composed of many subsystems, including the atmosphere, cryosphere, biosphere, and hydrosphere. Each component of the climate system has its own characteristics and response. Here at the University of Wisconsin–Madison, we are using appropriate observational information and numerical models of these components in an interactive system to study past and present climates and to make predictions about the future.
Understanding the climate system means, in part, understanding evolution of the past climate. We use paleorecords (from e.g. land, ice caps and marine sediments) and numerical climate models in conjunction with inverse techniques to reconstruct past climate change and to simulate natural climate variability. Modeling studies focus on the the decadal and interannual variability of climate, including the role of the ocean, while observations help us diagnose seasonal and intraseasonal variability in large scale atmospheric circulation.
On a global scale the radiative energy gained from the sun must be lost through infrared emission. Human activities are changing the atmospheric concentrations and distribution of greenhouse gases and aerosols, which in turn influences the energy available to the global Earth/atmosphere system. We develop and use numerical models of various climate subsystems and their couplings. We also employ observational evidence from satellites, aircraft, and ground based instruments to quantitatively predict future changes in the carbon cycle and the climate.
We are also interested in the implications for climate change of transport phenomena at the meso- to global scale; our particular strength is in studies of the upper troposphere and stratosphere. We use a variety of satellite and aircraft data, global meteorological analyses, and numerical models to address problems ranging ozone depletion to the influence of the quasibiennial oscillation on tropical convection.