Colloquium
Location
Physics : 401
Date & Time
March 10, 2014, 3:30 pm – 5:00 pm
Description
TITLE: Aircraft Observations and Modeling of Cloud and Aerosol Radiative Effect
ABSTRACT: Our ability to understand how solar energy is distributed and deposited on our planet has greatly improved over the past two decades, enabled by new global observing systems such as the NASA A--Train satellite constellation. But some of the outstanding questions regarding the radiative effects of atmospheric constituents and the surface cannot be answered with satellite observations alone because the derivation of surface and atmospheric energy budget terms from remote sensing requires a number of assumptions and parameterizations. Aircraft observations can fill some of these gaps because they allow the direct measurement of flux densities above, below and inside atmospheric layers of interest – alongsidein--situ measurements of atmospheric constituents and their optical properties. In my talk,I will show that the combination of airborne spectrally resolved radiation measurements with three--dimensional radiative transfer modeling allowed the resolution of a long--standing issue in so--called radiation closure experiments where cloud absorption from measurements appeared to be consistently higher than expected from the calculations. This led to the discovery of “colored” or spectrally dependent net horizontal photon transport, which is relevant not only to energy budget parameters such as radiative forcing and absorption, but also to remote sensing. The radiative effect of aerosols in homogeneous or inhomogeneous cloud fields can be understood as a spectral perturbation to the radiative signature of the underlying cloud field. Interpreting the combined signal from aerosols and clouds by means of their distinct fingerprints has become one of the goals of an emerging focus area: “cloud--aerosol spectrometry.” I will present some of the results of this new research direction and discuss how multiple observational techniques including spectral imaging and active sounding could be combined to gain a more complete understanding of the radiative effects of clouds, aerosols and gases in future research.
Location: Physics, Room 401
ABSTRACT: Our ability to understand how solar energy is distributed and deposited on our planet has greatly improved over the past two decades, enabled by new global observing systems such as the NASA A--Train satellite constellation. But some of the outstanding questions regarding the radiative effects of atmospheric constituents and the surface cannot be answered with satellite observations alone because the derivation of surface and atmospheric energy budget terms from remote sensing requires a number of assumptions and parameterizations. Aircraft observations can fill some of these gaps because they allow the direct measurement of flux densities above, below and inside atmospheric layers of interest – alongsidein--situ measurements of atmospheric constituents and their optical properties. In my talk,I will show that the combination of airborne spectrally resolved radiation measurements with three--dimensional radiative transfer modeling allowed the resolution of a long--standing issue in so--called radiation closure experiments where cloud absorption from measurements appeared to be consistently higher than expected from the calculations. This led to the discovery of “colored” or spectrally dependent net horizontal photon transport, which is relevant not only to energy budget parameters such as radiative forcing and absorption, but also to remote sensing. The radiative effect of aerosols in homogeneous or inhomogeneous cloud fields can be understood as a spectral perturbation to the radiative signature of the underlying cloud field. Interpreting the combined signal from aerosols and clouds by means of their distinct fingerprints has become one of the goals of an emerging focus area: “cloud--aerosol spectrometry.” I will present some of the results of this new research direction and discuss how multiple observational techniques including spectral imaging and active sounding could be combined to gain a more complete understanding of the radiative effects of clouds, aerosols and gases in future research.
Location: Physics, Room 401
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