Investigating the Atmospheric Boundary Layer Climatology of Dusty Arid Regions

  • Bushra Chalermthai

Student thesis: Master's Thesis

Abstract

Aerosols play a crucial role in the Earth sciences by affecting the radiative balance of the planet, modulating pathways through which clouds reflect and absorb sunlight, and influencing biogeochemical processes on lands and in the oceans. On the local scales, the concentration of the aerosols affects temperature, precipitation, visibility and climate variability in general. Regional/local impacts are particularly important in hot hyper-arid regions where aerosols and dust can directly influence the human health and well-being. The dynamics of dust and aerosols in the atmosphere is in turn strictly linked to the characteristics and the evolution of the atmo spheric boundary layer (ABL) - i.e. the lowest part of the atmosphere where most of the human activities take place. For example, the depth of the mixing layer within the ABL is connected with the dilution/concentration of dust and pollutants in the lower atmosphere, and with atmo spheric extinction - a crucial parameter in assessing the potential for solar energy harvesting. This research focuses on the climatology of the ABL in Abu Dhabi, United Arab Emirates and on its connection with the time-space distribution of dust and aerosols in the lower troposphere. Two years of high resolution attenuated backscattering profiles from a Vaisala CL31 ceilometer installed at the Masdar Institute Field station and aerosol optical depth (AOD) from the Masdar AERONET sun photometer, were used to assess the general climatology of the Abu Dhabi mixing layer and to infer extinction profiles for a number of different case studies. The potential of the joint usage of these two instruments was assessed based on different methods of inversions including the slope, Klett and optical depth methods and under different sky conditions. In all these methods, vertical extinction profiles can be obtained from the ceilometer backscatter through the inversion of the lidar integro-differential equation. Particularly encouraging results were obtained by combining the ceilometer inversion procedure with information on the mixing layer depth, here considered a proxy for the far-range altitude.
Date of AwardMay 2015
Original languageAmerican English
SupervisorAnnalisa Molini (Supervisor)

Keywords

  • Radiative Balance
  • Hot Hyper-Arid Regions
  • Dust & Aerosols
  • Boundary Layer
  • Solar Energy Harvesting.

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