ATS department ESS department

Research - Aerosols and Climate - Global Oceans

Shortwave Aerosol Radiative forcing from Satellites

Rationale:

Aerosols play a key role on the radiation balance of the earth-atmosphere system. The study of the radiative effects of tropospheric aerosols including mineral dust, organic carbon, black carbon, and sulfate have proved to be a challenging task due to the spatial and temporal variability of aerosol distribution and its properties. Current estimates of Shortwave Aerosol Radiative Forcing (SWARF) vary tremendously and the sign and magnitude of the radiative effect is still uncertain. Most aerosol studies use a modeling approach. We focus on using satellite data from NASA's Terra and Aqua satellites to study aerosol radiative effects over the global oceans by using a combination of CERES and Moderate-Resolution Imaging Spectroradiometer (MODIS) data sets from satellites.

Results:
Our results show that the use of satellite data for aerosol radiative forcing studies reduces many of the uncertanites commonly encountered in simulation approaches. The cloud free SWARF is -5.3 +-1.7 Wm-2 and the Northern hemisphere forcing is 1.5 times more than the Southern hemisphere.
For further inforamtion check out the following publications.

Zhang, J., S.A. Christopher, L.A. Remer and Y.J. Kaufman, Shortwave Aerosol Cloud-Free Radiative Forcing from Terra, I: Angular Models for Aerosols, J. Geophysical Research-Atmospheres, D10, S23, doi:10.1029/2004jd005008, 2005. (pdf file).
Zhang, J., S.A. Christopher, L.A. Remer and Y.J. Kaufman, Shortwave Aerosol Cloud-Free Radiative Forcing from Terra, II : Global and Seasonal Distributions, J. Geophysical Research-Atmospheres, D10, S24, doi:10.1029/2004jd005009, 2005. (pdf file).
Christopher, S. A., and J. Zhang (2004), Cloud-free shortwave aerosol radiative effect over oceans: Strategies for identifying anthropogenic forcing from Terra satellite measurements, Geophys. Res. Lett., 31, L18101, doi:10.1029/2004GL020510. (pdf file).
Christopher, S. A., and J. Zhang, 2002: Shortwave aerosol radiative forcing from MODIS and CERES observations over the oceans. Geophysical Research Letters, 29(18), 1859 - doi: 10.1029/2002GL014803 -18 September 2002, (pdf file)