24 Aug 2010
24 Aug 2010
A new method for deriving aerosol solar radiative forcing and its first application within MILAGRO/INTEX-B
K. S. Schmidt1, P. Pilewskie1, R. Bergstrom2, O. Coddington1, J. Redemann2, J. Livingston3, P. Russell4, E. Bierwirth5, M. Wendisch5, W. Gore4, M. K. Dubey6, and C. Mazzoleni6,7
K. S. Schmidt et al.
K. S. Schmidt1, P. Pilewskie1, R. Bergstrom2, O. Coddington1, J. Redemann2, J. Livingston3, P. Russell4, E. Bierwirth5, M. Wendisch5, W. Gore4, M. K. Dubey6, and C. Mazzoleni6,7
- 1Laboratory for Atmospheric and Space Physics, Boulder, CO, USA
- 2Bay Area Environmental Research Institute, Sonoma, CA, USA
- 3SRI International, Menlo Park, CA, USA
- 4NASA Ames Research Center, Moffett Field, CA, USA
- 5Leipzig Institute for Meteorology, University of Leipzig, Germany
- 6Los Alamos National Laboratory, Los Alamos, NM, USA
- 7Michigan Technological University, MI, USA
- 1Laboratory for Atmospheric and Space Physics, Boulder, CO, USA
- 2Bay Area Environmental Research Institute, Sonoma, CA, USA
- 3SRI International, Menlo Park, CA, USA
- 4NASA Ames Research Center, Moffett Field, CA, USA
- 5Leipzig Institute for Meteorology, University of Leipzig, Germany
- 6Los Alamos National Laboratory, Los Alamos, NM, USA
- 7Michigan Technological University, MI, USA
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Received: 14 Jan 2010 – Discussion started: 03 Feb 2010 – Revised: 19 Jun 2010 – Accepted: 06 Jul 2010 – Published: 24 Aug 2010
We introduce a method for deriving aerosol spectral radiative forcing along with single scattering albedo, asymmetry parameter, and surface albedo from airborne vertical profile measurements of shortwave spectral irradiance and spectral aerosol optical thickness. The new method complements the traditional, direct measurement of aerosol radiative forcing efficiency from horizontal flight legs below gradients of aerosol optical thickness, and is particularly useful over heterogeneous land surfaces and for homogeneous aerosol layers where the horizontal gradient method is impractical. Using data collected by the Solar Spectral Flux Radiometer (SSFR) and the Ames Airborne Tracking Sunphotometer (AATS-14) during the MILAGRO (Megacity Initiative: Local and Global Research Observations) experiment, we validate an over-ocean spectral aerosol forcing efficiency from the new method by comparing with the traditional method. Retrieved over-land aerosol optical properties are compared with in-situ measurements and AERONET retrievals. The spectral forcing efficiencies over ocean and land are remarkably similar and agree with results from other field experiments.
