Impacts of deforestation and oil palm plantation on the runoff-processes in humid tropical Sumatra, Indonesia

PI: Dr. T. Sayama
Funded by Kaken [website]

The impact of deforestation on floods in humid tropics is far from being understood due to a lack of observation regarding the rainfall-runoff processes. Our team’s initial field survey casts a research puzzle: Why are groundwater responses significant despite the hillslope being characterized by a thick clayey soil layer, which is typically highly impermeable?

To solve the puzzle, I investigated soil properties and runoff characteristics in a forested hillslope in Sumatra, Indonesia. I analyzed groundwater and soil moisture records, conducted soil experiments, and simulated the vertical infiltration.

Publication https://doi.org/10.3178/hrl.15.23

Quantifying temporal surface-subsurface dynamics from in-situ soil moisture network observation under different land uses

Advisor: Dr. H. McMillan

Soil moisture controls energy and water cycles. However, soil moisture data are not often used for model evaluation due to lack of process-based diagnostic tools. Recent studies have developed hydrologic signatures that can characterize the dynamic aspects of the hydrologic data (Branger and McMillan, 2019). We can diagnose hydrologic models based on whether the model successfully reproduced the hydrologic signatures.

My Master’s project aims to quantify the soil moisture dynamics by developing soil moisture signatures and applying them to in-situ soil moisture network data worldwide under diverse hydroclimatic environment. I further aim to derive the process implications from the signatures, such as partitioning and storage processes.

Canyon flow analysis with particle velocity imagery (PIV) technique in San Diego

PI: Dr. H.McMillan
[Movie for outreaching]

Traditional measurements of river flow rates require contact with the flow. With the PIV (particle image velocimetry) technique, we can obtain the river surface’s 2-D velocity field without entering the river. PIV cross-correlates the particle in sequential images of the flowing river surface.

Out group aims to assess the effectiveness and uncertainties of the PIV technique in small rivers (the river width around less than 10 metres). I am working on the setting and assessment of the field sites and PIV analysis.

Snowmelt processes in the National Water Model during extreme Atmospheric River events

Intern advisor: Dr. H. McMillan, Dr. Ty Brandt, Dr. Edwin Sumargo, Dr. Forest Cannon
Funded by NOAA


National Water Model (NWM) is a hydrologic model that simulates the streamflow over the entire continental United States developed by NOAA. The primary question we should ask is: how well does global model reproduce regional phenomena? The project aims to assess and improve the prediction of rapid snowmelt caused by Rain-on-Snow events in the Sierra Nevada and Cascade mountains by NWM.

I am doing an internship at the Center for Western Weather and Water Extremes at UC San Diego on the project. I am working on reviewing literature, compiling hydro-climatic data, and analyzing the soil moisture data.

Isotope streamflow analysis in semi-arid urban region, San Diego

PI: Dr. H. McMillan

Our group is working on the identifying source of water in highly modified urban rivers in arid San Diego with isotope analysis EMMA.

I am assisting the data cleaning and literature review about uncertainty in EMMA procedure.