Seminar: Thurs., Feb. 20, 4:10 pm, EN1062
The Radiative Effects of Atmospheric Constituents: A Detailed View from Aircraft Observations
University of Colorado
Laboratory for Atmospheric and Space Physics
Despite significant advancements in space-‐borne remote sensing of atmospheric constituents over the past two decades, several important findings related to the energy budget of our planet have in fact been obtained from airborne and ground-‐ based measurements of atmospheric radiation paired with in-‐situ characterization of cloud, aerosol and gas properties. This is not surprising because aircraft measurements allow the direct and detailed observation of relevant quantities such as flux densities within, above and below layers of interest; this is in contrast to satellite-‐based estimates which require a number of assumptions and parameterizations to derive those quantities. In my talk, I will show that a long-‐ standing issue in atmospheric radiative transfer, the discrepancy between measured and calculated cloud absorption, was recently explained by using a combination of spectrally resolved radiation measurements (not available in space) and three-‐ dimensional radiative transfer 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. I will present first results from an emerging research direction, “cloud-‐aerosol-‐gas spectrometry,” which studies the combined radiative effects of atmospheric constituents in heterogeneous conditions. We are only beginning to understand the ramifications of the new findings for atmospheric dynamics, energy budget, and remote sensing. Future aircraft observations can continue to reconcile the perspective “from above” with the detailed view “from below and within,” especially when merging complementary observations such as spectral imaging and active sounding on a single or on multiple platforms.