• Dr. Martin Mlynczak
  • NASA Langley Research Center
  • 135 Goodwin Hall
  • 4:00 p.m.
  • Faculty Host: Dr. Joseph Schetz

Atmospheric science is relentlessly driven by the need for observations. Weather forecasts rely on satellite and ground based observations to provide the initial conditions which are integrated forward in time to produce the forecast. Chemists rely on measurements of ozone and other minor species to assess the atmosphere’s ability to shield Earth’s surface and inhabitants from harmful ultraviolet radiation. Climate scientists use measurements of incoming solar radiation and the outgoing infrared radiation from the Earth to assess the energy balance of the planet. Aeronomers and space scientists use observations of the high atmosphere to understand the interaction of the Sun and the atmosphere extending hundreds of km above Earth’s surface. Many of these observations are provided by measuring components of the infrared emission spectrum of the Earth and its atmosphere. In this talk I will review some of the basic principles of infrared radiative transfer in Earth’s atmosphere and show how measurement of the infrared spectrum can be used to derive temperature, density, minor species (e.g., ozone) abundances, as well as energetic constraints on the atmospheric climate. I will give special emphasis on results in Earth’s mesosphere and thermosphere obtained from the NASA TIMED satellite and its infrared sensor, the SABER instrument. We will show how the variability of the Sun (both the ultraviolet photons emitted from the Sun and the solar wind) can drive large changes in the upper atmosphere on timescales ranging from days to decades. I will conclude by discussing long-term changes in the upper atmosphere associated with increasing carbon dioxide, and the effects this may have on atmospheric density and the lifetime of orbiting objects.