Date of Award
Summer 2026
Language
English
Embargo Period
4-2-2027
Document Type
Master's Thesis
Degree Name
Master of Science (MS)
College/School/Department
Department of Atmospheric and Environmental Sciences
Program
Atmospheric Science
First Advisor
Fangqun Yu
Second Advisor
Sara Lance
Committee Members
Fangqun Yu, Sara Lance
Keywords
dust, aerosol, ice clouds, upper troposphere
Subject Categories
Atmospheric Sciences | Meteorology
Abstract
Dust aerosol is relevant to ice particle physics via its ability to act as ice nuclei. While dust in the upper troposphere has been characterized by different approaches, there is room to improve our understanding of seasonal variations in dust number concentrations (ππ) and size (ππππ). Analysis of dust variations with respect to mixed phase and ice clouds could prove insightful. GEOS-Chem APM dust size distributions are validated against observations, then used to study the size-resolved climatology of dust in three regimes related to temperature and ice microphysics (mixed phase, ice - troposphere, ice - tropopause/stratosphere). Then, correlation analysis of interannual dust number concentration variability is used as a first step to understand springtime dust source contributions relevant for each regime. While dust number concentrations and size decrease from the mixed phase regime to the ice - troposphere regime, dust depletion from the troposphere to the tropopause/stratosphere is more strongly pronounced, especially for large particles. Geometric mean ππ in 40N - 50N drops by approx. 10x for most particle sizes from the mixed phase to the ice - troposphere regime but by multiple orders of magnitude for π·π>0.5ππ from ice - troposphere to ice - tropopause/stratosphere. In the Northern Hemisphere mid-latitudes, monthly mean dust number concentrations (π·π>0.09ππ) vary by approximately a factor of 10, with a springtime peak that matches the seasonality reported in the literature. The magnitude of monthly variations increases with particle size, and this effect becomes more prominent with altitude. For tropospheric dust in the ice - troposphere regime, number concentrations of particles with π·π>2.5ππ vary by about 150x. The contrast in tropospheric dust concentrations between the Northern and Southern Hemisphere mid-latitudes is strongest in MAM, with ππ being approx. 10x - 100x larger in the Northern Hemisphere for both the mixed phase and ice - troposphere regimes. Effective radius is generally larger in the Northern Hemisphere than the Southern hemisphere during this season. Correlation analysis shows signs of the eastwards transport of dust from the Tibetan Plateau to North America in the mixed phase regime. In the ice - troposphere regime, correlations to different dust sources (the Sahara, West Asia, and East Asia) are broadly stratified with latitude. Dust variability in the ice - tropopause/stratosphere regime correlates with dust variability in the West Asia source region. The implications of these results for understanding dust INP physics are discussed.
License
This work is licensed under the University at Albany Standard Author Agreement.
Recommended Citation
Ghosh, Sarothi, "High Altitude Size-Resolved Dust Climatology and First Steps Towards Source Attribution" (2026). Electronic Theses & Dissertations (2024 - present). 528.
https://scholarsarchive.library.albany.edu/etd/528