Semester of Graduation

Summer 2019

Degree

Master of Science in Engineering Science (MSES)

Document Type

Thesis

Abstract

Dry and wet deposition of nitrogen (N) and sulfur (S) has detrimental impacts on the health of both human and ecosystems. Intensive human activities are responsible for elevating emissions and deposition of N and S species. Large population and fast industrial development led China to one of the countries with highest acid deposition. The large fluxes of N and S deposition have caused acidification of surface water and soil, which damages plant growth and biodiversity in China. N and S deposition has been investigated using ground-based monitoring networks and satellite-based sensors. The limitation of location of monitoring sites and performance of sensors caused lack of data availability of N and S deposition for the whole China. Chemical transport models (CTMs) have been used to study the distribution and trends of N and S deposition in both global and regional scales. In this thesis, the WRF/CMAQ modeling system is used to study dry and wet deposition of N and S components in winter and summer episodes of 2015 and 2046 in China. A source-oriented technique is employed to study the source apportionment of N deposition to the 10 largest lakes in China. This study obtained temporal and spatial distributions and major species of N and S deposition. The source apportionment results suggest that agriculture, industry, power generation, and transportation are the top four sources of N deposition. Dry deposition is dominated by gas phase and wet deposition is dominated by aerosol phase. Meteorology and deposition changes under three future emission scenarios (RCP 4.5, 6.0, and 8.5) are predicted from 2015 to 2046. The overall distribution of total N and S deposition does not change substantially from 2015 to 2046. Deposition rates of major N and S species change accordingly under three RCPs. Future changes of temperature and relative humidity may alter future wet deposition rates and changes of wind speed and direction may have effects on dry deposition rates. For future N deposition to lakes, dry deposition decreases for all RCP scenarios in 2046. RCP 8.5 has higher deposition rates than other two scenarios. Wet deposition changes differently for each RCP.

Committee Chair

Zhang, Hongliang

Available for download on Wednesday, May 11, 2022

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