Xiaogang HE's website

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Welcome to Xiaogang HE's website!

Mail: hexg @ nus.edu.sg

Research Summary

My overall research interests aim at developing an integrated modeling framework, which is physically motivated and data-driven, across disciplines and scales to improve our fundamental understanding of water-related natural hazards and their societal impact through the lens of the coupled human-natural system.

Specifically, my research interests focus on:

(1) Formulating a statistical framework to robustly quantify and diagnose likely trends and variability in flood and drought risk, the intersection between the two phenomena, and their cascading, compounding impacts, that has resulted in the first global drought and flood catalogue.

(2) Developing a physical framework to conduct attribution analysis to disentangle how climate change, variability and human interventions (e.g., irrigation, reservoir operation, groundwater pumping) influence floods and droughts at regional and continental scales.

(3) Designing a coupled hydrological and agent-based model to formulate effective mitigation and adaptation policies of natural disasters, through the incorporation of human behaviors and decisions into existing risk assessment frameworks.

(4) Developing a hydro-economic model to identify possible solutions and optimal development pathways towards better management of water-related trade-offs (i.e., energy production and irrigation in California) and environmental sustainability (i.e., groundwater depletion) within the framework of water-food-energy nexus.

(5) Developing a novel machine learning based algorithm for high-resolution precipitation downscaling.

These work laid the foundation for me to continue thinking about "big" questions about the future state of the planet and the sustainability of current practices, as well as building state-of-science capabilities to solve most pressing future challenges.

News

New!! Recent GRL paper highlighted by PNAS Journal Club

My recent work looking at how human water management can influence the 2011-2014 California surface water drought has been published in Geophysical Research Letters (GRL) and highlighted by Proceedings of the National Academy of Sciences (PNAS)! Check the details in our paper and the short article appeared in PNAS Journal Club!

New!! Accepted to IIASA'S 2017 Young Scientists Summer Program

I have been accepted to the 2017 Young Scientists Summer Program (YSSP) at International Institute for Applied Systems Analysis (IIASA) in Laxenburg, Austria from Jun 1 to Aug 31. I was selected as one of 53 YSSP participants out of 340 applicants from over 30 countries. At IIASA, I will be working with Dr. Yoshihide Wada, deputy director of the Water Program, to investigate drought adaptation options using an integrated hydrological and agent-based model built on my recent California drought study. The overall objective of my proposed project is to include agents' behaviors/decisions in the current state-of-the-art hydrological model to have a more realistic representation of the reciprocal interactions and feedbacks between human and natural systems so as to inform policy-making that copes with climate change for drought mitigation and adaptation.

Paper Published in Journal of Hydrology

My paper "Development of a coupled hydrological-geotechnical framework for rainfall-induced landslides prediction" has been published in JoH! Working with Dr. Humberto Vergara, I developed a new model called CRESLIDE, which can predict storm-triggered cascading flood and landslides by coupling a distributed hydrological model (CREST) and a slope stability model (SLIDE). This coupled model can be used to deliver an operational early warning and forecasting system at a much larger scale (e.g., global scale) due to its computational efficiency and with the aid of satellite remote sensing datasets (Paper).

Paper Published in Water Resources Research

My paper "Spatial downscaling of precipitation using adaptable Random Forests" has been published in WRR! This paper introduces a novel data mining algorithm called Prec-DWARF (Precipitation Downscaling With Adaptable Random Forests) for spatial precipitation downscaling, which can well maintain the complex geometrical and statistical characteristics of precipitation. The general flexibility of Prec-DWARF enables its application to a variety of situations and datasets and it also demonstrates the potential of machine-learning based techniques in the field of hydrologic, atmospheric and climatic sciences (Paper).

SMAP Field Campaign @ Tombstone, AZ

Julian, a visiting student from University of Copenhagen, and I participated in the SMAPVEX15 (Soil Moisture Active Passive Validation Experiment 2015) from July 31 to Aug 6 in Tombstone, Arizona. This field campaign is designed to address post-lunch SMAP soil moisture product through the aircraft-based and ground-based observations in the USDA-ARS Walnut Gulch Experimental Watershed. 50+ scientists and students from the U.S. agencies and U.S. and international universities are involved over this monsoon season. We did a lot of interesting measurements there, including soil moisture sampling, vegetation sampling, roughness, bulk density and infiltration measurement. It has also been a nice experience to make so many friends with different background during this campaign!!

Book Chapter Available in Springer

My work at HyDROS lab entitled "Landslides susceptibility mapping in Oklahoma state using GIS-based weighted linear combination method" has been collected in the book "Landslide Science for a Safer Geoenvironment" on Springer! A first-cut landslide susceptibility map over the state of Oklahoma has been generated through the GIS-based weighted linear combination method by combining the GIS and high resolution satellite images (Paper).

Paper Published in Environmental Research Letters

My co-authored paper "Solar cycle modulation of the Pacific-North American teleconnection influence on North American winter climate" has been published in ERL! Our work presents for the first time an analysis of solar modulation of Pacific North American (PNA) teleconnection influence on North American winter climate (Paper).

Paper Submitted to Weather and Forecasting

This work is a summary of my master thesis, which is focused on the diurnal cycle of precipitation over West African Monsoon Region (Abstract). Thank you for all the co-authors' contribution!

Joined HyDROS Lab as a Visiting Scholar

I will be a visiting scholar at the Hydrometeorology and Remote Sensing (HyDROS) laboratory from this September.

HyDROS is located in the National Weather Center (NWC), Norman, Oklahoma. It is affiliated with the Advanced Radar Research Center (ARRC), National Severe Storms Laboratory (NSSL), Water Technology for Emerging Regions Center (WaTER) and the School of Civil Engineering & Environmental Science (CEES) of the University of Oklahoma (OU).

ALMIP2 Workshop

I participated in the ALMIP2 Workshop at International Conference Center (CIC), Meteo-France, Toulouse, France from Apr 15th to Apr 17th. I had an oral presentation to introduce the model configuration of MATSIRO land surface model.

During this workshop, we mainly discussed about preliminary results at three meso-scale domains (Benin, Mali and Niger). We also discussed about the meso-scale reruns, additional simulations, local experiments and future publication timetable, strategy and conferences.

2012 AGU Fall Meeting

I participated in the 2012 AGU Fall Meeting at San Francisco from 3rd Dec to 7th Dec, 2012. It was the first time for me to attend such an acedamic pageant. I had a poster presentation and a coauthored oral presentation.

Hydro Group River Excursion

The Hydro-Environmental Group at the Department of Civil Engineering, the University of Tokyo has river excursion every year.

This year we visited Ashio Cooper Mine, Kusaki Dam, Watarase Retarding Basin, Edogawa Branch Point and other hydrologic infrastructures near Watarase River.

Nishino Akiyo Prize

I'm awarded the Nishino Akiyo Prize for Japanese language learning.

I really enjoy the time learning both from sensei and friends at the Japanese Language Class in Civil Engineering! Thank you!

Post-flood Field Survey in Thailand

I participated in the post-flood field survey in lower Chao Phraya river basin from Aug 6th to Aug 8th. Our team mainly visited different level's offices to get to know how they responded to last year's huge flood and what the current situation for the disaster management system is. We visited Suphan Buri provincial office, Ayutthaya RID office, Ban Chang sub district office and Bang Ban project office. Besides this, we also conducted interview with the local people in Suphan Buri to investigate their living conditions during the flood and how they felt about the irrigation system and flood protection system.

IMPAC-T Workshop

I joined the IMPAC-T (Intergrated Study on Hydro-Meteorological Prediction and Adaptation to Climate Change in Thailand) Workshop which was held at KU Home of Kasetsart University, Bangkok. Our team reported the field survey results in lower Chao Phraya river basin.

Two Abstracts Submitted to 2012 AGU Fall Meeting

Two abstracts were submitted to 2012 AGU Fall Meeting. One is related to ALMIP2 project and the other is about groundwater storage estimation.

Participated in an International Project ALMIP2

Encouraged by Prof. Oki, I participated in an international project AMMA Land Surface Model Intercomparison Project Phase 2 (ALMIP2). The main purpose of this project is to obtain a better understanding of the intra-seasonal and interannual variability of the West-African monsoon.

Japan Conference on Hydraulic Engineering (JCHE)

JCHE is one of the biggest conferences of Hydraulic Engineering in Japan. This year's conference was held at Ehime University, Matsuyama-shi from Mar 6 to Mar 8. It is the first time for me to attend an academic conference, although most of the lectures were in Japanese.

Paper Accepted by Journal of Hydroelectric Engineering

My paper "Prediction of Monthly Inflow to the Danjiangkou Reservoir based on Distributed Hydrological Model and Hydro-climatic Teleconnections" has been accepted! This paper originates from my bachelor thesis.