Graduate Thesis Or Dissertation


Quantifying Cloud-Aerosol-Radiation Interactions Using Airborne and Surface-Based Observations, With a View Towards The Arctic Public Deposited
  • In this thesis I use active and passive remote sensing measurements to study topics pertaining to the interactions between clouds, aerosols, and solar radiation in the Arctic. After an introduction to the topics in Chapter 1, the second chapter presents observational evidence that sulfate aerosols inhibit the production of ice in Arctic low-level mixed-phase clouds. This study primarily utilizes a years-long statistical record of radar-derived cloud ice water content to study differences in cloud ice amount under varying surface aerosol concentrations. The second part of the thesis focuses on tool development for remote sensing of clouds and aerosols: first a multi-step retrieval of Arctic cloud and surface optical properties from measurements of spectral downwelling irradiance is established. The third chapter demonstrates that the radiative effect of clouds over snow- and ice-covered surfaces can be derived using a simple radiometer configuration. The method is shown to be best suited for environments with high surface albedo, which is often the case for Arctic land and sea-ice surfaces. Such advancement of remote-sensing will improve our ability to study how changes in Arctic cloud microphysics, like those discussed in the second chapter, impact the surface radiative environment of the region. The fourth chapter explores techniques to simultaneously derive cloud and aerosol optical depth with a prototype total-diffuse spectral radiometer mounted atop a research aircraft. There are two aspects to this final study: First, retrievals that derive the optical depth of cirrus and aerosol layers, for states when the layers occur in isolation, are developed and validated. Then it is demonstrated that these new methods can be used to simultaneously retrieve the cirrus and aerosol layer optical depths. While the techniques described in the fourth chapter are established and tested at lower latitudes, they are also applicable to Arctic environments where cirrus are ubiquitous.

Date Issued
  • 2021-11-12
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Last Modified
  • 2022-12-13
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