James E. Hansen
Columbia University
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Primary Section: 16, Geophysics Membership Type:
Member
(elected 1996)
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Research Interests
As a physicist, I have studied atmospheric radiation, both from the standpoint of using remote measurements of radiation to deduce information on the structure of planetary atmospheres and from the standpoint of trying to understand the possible climate effects of a change of planetary radiation balance. In the former category, with the help of computer simulations of multiple scattering of light, I have analyzed the information on aerosols and clouds contained in measurements of reflected sunlight. Such information has helped determine the composition of the Venus clouds, and it is of potential value for satellite monitoring of aerosol and cloud properties on Earth. Recently I have focused on quantitative analysis of radiative forcing mechanisms, that is, alterations of the Earth's radiation balance with space, such as changes of carbon dioxide, ozone, aerosols, or solar irradiance, which would tend to alter climate. The studies involve both the development of global numerical models of the climate system and analysis of global observations, with the aim of trying to help understand the sensitivity of the climate system to such radiative perturbations.
