Atmosphere and Climate Research at MIT

Atmospheric processes are central to many of the forcings and feedbacks that determine the magnitude of climate change. The atmosphere is also central to many of the possible impacts of climate change, such as changes in the intensities of tropical and extratropical storms and changes in the character of precipitation.

PAOC researchers are investigating how the chemical evolution of the atmosphere and ongoing emissions of greenhouse gases affect the climate system. Atmospheric feedbacks include changes in water vapor concentrations and cloud distributions, and so a proper understanding of atmospheric processes is needed to determine how the climate system responds to a given radiative forcing. Changes in aerosols and ozone also affect the climate system, and again there is the possibility of a complex interplay between radiative forcing, cloud and convective processes, and the circulation. Changes in the temperature and energetics of the climate system are expected to affect weather patterns. PAOC researchers have found that the transient eddies in the extratropical atmosphere (the familiar high and low pressure systems in the midlatitudes) increase or decrease in strength in response to a general warming depending on the hemisphere and season. In fact, there may be an ''optimally stormy'' climate state for the midlatitudes, and it is of interest to discover if such a state has occurred over Earth's history. The question of whether tropical storms intensify in a warming climate is made difficult by our inability to properly resolve such storms in global climate model simulations. PAOC researchers address this problem using theoretical bounds on intensity, analysis of the historical record, use of paleo-proxies for land-falling storms, and a range of regional models of the tropical atmosphere.