Ph.D. Dissertation Defense

Exploiting Subsurface Ocean Dynamics for Decadal Predictability in the Upwelling Systems of the Eastern North Pacific

Given the strong recent interest in the decadal timescale variability and the potential for its predictability, it is critical to identify dynamics that carry inherent decadal-scale predictability. This work enhances our understanding and prediction capability of the subsurface signature of the decadal variability in the eastern North Pacific upwelling systems using reanalysis products and a set of eddy-resolving ocean model simulations.

Tropospheric O3 modeling study: Contributions of anthropogenic and biogenic sources to O3-CO and O3-CH2O correlations

This dissertation employs DISCOVER-AQ aircraft experiments and 3-D chemical and transport model to study the contributions of different sources to the  correlation of O3-CO and O3-CH2O on different scales, and the implements of O3 estimation using the correlations and concentrations of CO and CH2O.

Applications of satellite retrievals in deriving pollutant emissions and trends

This dissertation employs various satellite retrievals and the 3-D Regional chEmical trAnsport Model (REAM) to (1) identify and quantify the emission sources, and (2) derive pollutant trends.

First, we use short-lived reactive aromatics as proxies to diagnose transport of pollutants through the Himalayas to Tibet. We find enhancements of reactive aromatics over Tibet by a factor of 6 on average due to rapid transport from India and nearby regions during the presence of a high-altitude cut-off low system.

A Multiscale Analysis of Heat Transfer in Porous Media

The modeling of thermal convection in porous media is a challenging task due to the inherent structural and thermophysical heterogeneities that permeate over several scales. In the present thesis, we address several issues relevant to buoyancy driven thermal convection in porous media. Our approach is based on establishing a multi-scale framework build on knowledge accrued by theoretical, numerical and experimental methods.

DYNAMICAL FOOTPRINTS OF AEROSOLS IN EXTRATROPICAL ATMOSPHERIC DISTURBANCES AND CIRCULATION: A MODELING ANALYSIS

Synoptic-scale atmospheric disturbances occupy extratropics in wintertime and form extratropical “storm tracks”. These disturbances not only influence day-to-day weather variability but also modulate regional climates. The region of the North Pacific storm track is also known to be characterized by high concentrations of atmospheric aerosols, making it an ideal location for investigating the interaction between aerosols and extratropical disturbances.

INTERACTIONS BETWEEN CLIMATE VARIABILITY AND AIR POLLUTION ―A STUDY OF SEVERE HAZE AND LARGE WILDFIRES

The drastically changing climate system plays a critical role in modulating emission and distribution conditions of air pollutants including greenhouse gases, aerosols, and tracer gases, while these air pollutants exert significant feedback to the climate system through multiple biogeophysical, biogeochemical, and hydrological pathways. These interactions occur at different spatial and temporal scales that increase the difficulty for a clear and comprehensive understanding.

Improving the fidelity of coral-based climate records: A roadmap for bypassing intercolony variability and diagenesis

The tropics are a critical part of climate system, modulating global temperature and precipitation patterns on a variety of timescales. Yet, natural climate variability across much of the tropics remains poorly characterized due to the dearth of instrumental observations prior to 1970s. Massive corals are now routinely used to reconstruct past tropical climate variability, however the accuracy of these records have been questioned as corals growing on the same reef can produce very different geochemical signals.

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