Zhou's Research

Tiantian Zhou

Postdoctoral researcher

Email: tzhou035@ucr.edu; tiantianzhouonly@gmail.com

Education

Ph.D. Environmental Sciences, University of California-Riverside (UCR), CA, USA, 2022 

M.S. Physical Geography, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China, 2018.

B.E. Hydrology and Water Resources Engineering, Taiyuan University of Technology, Taiyuan, Shanxi, China, 2015.

Research Interests

Agriculture hydrology

Stable isotopes applications

Numerical modeling of subsurface hydrology

Global sensitivity analysis and parameter estimation

Research Descriptions

My research is centered on solving fundamental questions in Earth Surface Processes, with a particular focus on quantifying and tracking water and solute movements across the groundwater, soil, plant, and air continuum (GSPAC). 

In stable isotope tracing, I used stable isotope signals (²H and ¹⁸O) from precipitation and soil water to investigate hydrological processes like mixing and evaporation in cotton fields under mulched drip irrigation during my master’s research at the Chinese Academy of Sciences with Dr. Dongmei Han. During my PhD at UC Riverside with Dr. Jiří Šimůnek and my postdoc at the University of Arizona with Dr. Peter Troch, I applied the Bayesian mixing model (SIAR) to identify plant water sources. I also compared four methods for estimating soil water ages and the temporal origin of root water uptake at various sites, including a lysimeter, a sandy barrier island, and three hillslopes. The methods used were: (a) StorAge Selection (SAS) functions, (b) non-parametric estimation in flow-weighted time, (c) particle tracking, and (d) flux tracking, based on isotopic compositions of soil water and discharge measurements. 

In isotope transport and fate modeling, I developed an isotope transport module for HYDRUS-1D during my PhD study at UC Riverside with Dr. Jiří Šimůnek. This module incorporates various complex evaporation fractionation scenarios of stable isotopes (²H and ¹⁸O). I tested it against analytical solutions and studied how evaporation fractionation affects the estimation of soil hydraulic and isotope transport parameters. Using global sensitivity analysis (Morris and Sobol’) and particle swarm optimization in Python, I assessed how variations in parameter estimation could introduce uncertainty into stable isotope tracing applications. 

In contaminant transport and fate modeling, I focused on contaminant transport and fate modeling, utilizing HYDRUS models, Python-based numerical analysis, and towed transient electromagnetic (tTEM) data to study pesticide transport under agricultural managed aquifer recharge (Ag-MAR) during my postdoc at UC Davis with Dr. Helen Dahlke. My research assessed the accuracy and uncertainty of HYDRUS-1D, investigated the influence of vadose zone heterogeneity on preferential flow, water balance, and pesticide leaching efficiency, and evaluated the risks of groundwater contamination associated with Ag-MAR. 

Publications

Conference Presentations

Selected Awards