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Radiative Forcings

Contacts, for more information:

Atmospheric radiative transfer is the science of understanding how electromagnetic radiation emitted by both the Sun and Earth interacts with the gases, clouds and particles making up our atmosphere. The changes in energy due to these interactions are responsible for many variations in temperature and weather that we experience in everyday life. For example, cloudy nights are normally warmer than clear nights because of radiative transfer processes, with the nighttime clouds reducing the energy lost to space by the surface of the planet. The science of radiative transfer also explains a wide range of beautiful natural events, such as rainbows, moon halos, sundogs and the color of the sunset. On longer timescales, the processes by which energy leaving the Earth is altered by increased atmospheric greenhouse gases, such a H2O and CO2, is explained by radiative transfer.

In a general circulation model (GCM), radiative transfer translates changes in atmospheric constituents, such as clouds, aerosols, water vapor, and CO2, into changes in energy reflected, absorbed or emitted by the atmosphere. Accurate radiative transfer calculations are therefore required to model how the global climate system will be altered in response to changes in both anthropogenic and natural emissions.

GFDL Research

In order to have the most accurate and up-to-date radiative transfer science in our GCMs, we are carrying out research that varies from incorporating improved understanding of water vapor spectroscopy (Paynter and Ramaswamy, 2012) to using global observing systems to validate our GCM energy balance at the surface (Freidenreich and Ramawamy, 2011). Understanding the radiative transfer of the stratosphere and how this impacts global temperature is also another area of research expertise at GFDL (Schwarzkopf and Ramswamy, 2008, Austin et al., 2013).
Our main objectives are to maintain radiative transfer codes for usage in GFDL models; to maintain a line by line radiative code; to make use of the latest theoretical and measurement data within the radiation codes; to benchmark and test our radiation codes against other codes and measurement data; and to actively participate in radiative transfer inter-comparison projects. Our ultimate goal is to understand and evaluate the impact of radiative transfer upon climate simulations.

The flux per a wavenumber calculated for the CIRC case 2 atmosphere, as modeled by the RFM line by line code.


  1. Bollasina, Massimo, Yi Ming, V Ramaswamy, M Daniel Schwarzkopf, and Vaishali Naik, January 2014: Contribution of Local and Remote Anthropogenic Aerosols to the 20th century Weakening of the South Asian Monsoon. Geophysical Research Letters, 41(2), DOI:10.1002/2013GL058183.
  2. Fry, M, M Daniel Schwarzkopf, Z Adelman, and J J West, January 2014: Air quality and radiative forcing impacts of anthropogenic volatile organic compound emissions from ten world regions. Atmospheric Chemistry and Physics, 14(2), DOI:10.5194/acp-14-523-2014.
  3. Naik, Vaishali, Larry W Horowitz, Arlene M Fiore, Paul Ginoux, Jingqiu Mao, A M Aghedo, and Hiram Levy II, July 2013: Impact of preindustrial to present day changes in short-lived pollutant emissions on atmospheric composition and climate forcing. Journal of Geophysical Research, 118, DOI:10.1002/jgrd.50608.
  4. Austin, John, Larry W Horowitz, M Daniel Schwarzkopf, R John Wilson, and Hiram Levy II, June 2013: Stratospheric Ozone and Temperature Simulated from the Preindustrial Era to the Present Day. Journal of Climate, 26(11), DOI:10.1175/JCLI-D-12-00162.1.
  5. Fry, M, M Daniel Schwarzkopf, Z Adelman, Vaishali Naik, W J Collins, and J J West, May 2013: Net radiative forcing and air quality responses to regional CO emission reductions. Atmospheric Chemistry and Physics, DOI:10.5194/acp-13-5381-2013.
  6. Bowman, K W., Larry W Horowitz, and Vaishali Naik, April 2013: Evaluation of ACCMIP outgoing longwave radiation from tropospheric ozone using TES satellite observations. Atmospheric Chemistry and Physics13(8), DOI:10.5194/acp-13-4057-2013.
  7. Shindell, D, Larry W Horowitz, and Vaishali Naik, et al., March 2013: Radiative forcing in the ACCMIP historical and future climate simulations. Atmospheric Chemistry and Physics, 13(6), DOI:10.5194/acp-13-2939-2013.
  8. Stevenson, D, Vaishali Naik, and Larry W Horowitz, et al., March 2013: Tropospheric ozone changes, radiative forcing and attribution to emissions in the Atmospheric Chemistry and Climate Model Inter-comparison Project (ACCMIP). Atmospheric Chemistry and Physics, 13(6), DOI:10.5194/acp-13-3063-2013.
  9. Paynter, David J., and V Ramaswamy, August 2012: Variations in water vapor continuum radiative transfer with atmospheric conditions. Journal of Geophysical Research, 117, D16310, DOI:10.1029/2012JD017504.
  10. Fry, M, Vaishali Naik, J J West, M Daniel Schwarzkopf, and Arlene M Fiore, et al., April 2012: The influence of ozone precursor emissions from four world regions on tropospheric composition and radiative climate forcing. Journal of Geophysical Research, 117, D07306, DOI:10.1029/2011JD017134.
  11. Paynter, David J., and V Ramaswamy, October 2011: An assessment of recent water vapor continuum measurements upon longwave and shortwave radiative transfer. Journal of Geophysical Research, 116, D20302, DOI:10.1029/2010JD015505.
  12. Freidenreich, Stuart, and V Ramaswamy, April 2011: Analysis of the biases in the downward shortwave surface flux in the GFDL CM2.1 General Circulation Model. Journal of Geophysical Research, 116, D08208, DOI:10.1029/2010JD014930.