Chao Wang Researcher Feature: Remote Sensing Nature-Human Systems

About me:

My name is Chao Wang and I am currently a postdoc at University of North Carolina at Chapel Hill. My overall research interests lie within the transdisciplinary research fields of hydrology, land use, and socioeconomics, and how they can be used to understand the broader nature-human system at different spatiotemporal scales.

I earned both Bachelor and Master of Science degrees in Geospatial Analysis from Anhui Normal University, China. In 2019, I completed my PhD at the Environmental Sciences program at the University of Puerto Rico. I believe that having different cultural backgrounds and big-picture vision helps me understand the diversity of people and the world so that I can contribute to the knowledge of achieving sustainable and resilient environments in the future, especially in the era of Climate Change. Right now, I am extremely interested in investigating how remote sensing observations can uncover the causes, impacts, and consequences of water cycle dynamics and water resource management, as well as extreme weather events. 

How did you end up in the field of Hydrology? 

In the second year of junior high school, I started taking a general physics class. The teacher was really nice to me, and I began to love science and wanted to do something with science. I started my undergraduate studies in Geospatial Analysis after my high school friend showed me Google Earth on his computer. I was so excited about using remote sensing to study surface changes during my PhD. I first collaborated with my college friend, a hydrologist who was interested in small, urban water bodies. Since then, we have discussed and studied hydrology research that uses satellite observations. In particular, my friends and I started to study climate trends by observing the long-term dynamics of alpine lakes, as they are a key indicator of climate change. For my postdoctoral study, I am working with Dr. Tamlin Pavelsky on advanced remote sensing tools for hydrology studies at UNC’s Global Hydrology Lab.

Give us an elevator pitch of your last paper? 

Did you know that scientists predict that coastal areas will lose $1 trillion a year to flooding by 2050? The reliability of flood mapping directly affects efforts to build resilient coastal communities. Airborne and spaceborne remote sensing platforms have revolutionized our ability to accurately map floods; however, low revisit frequency and persistent cloud cover during extreme weather events limit the use of optical satellite imagery in rapid response flood mapping. Radar sensors provide their own illumination and are therefore unaffected by atmospheric conditions. Additionally, the high dielectric constant of water and bright returns from flooded forests make radar useful for fully characterizing the extent of flood inundation. My research focused on leveraging daily airborne longwave radar signals to observe the dynamics of flooding changes along the river floodplain in North Carolina. It is proven to accurately capture the rapid receding of floodwaters within 1-2 days, which has never been observed before in this dense forested landscape.

What is one of common misconception questions in your research field? 

Many people who are obligated to buy renter’s insurance that includes flood damage will wonder, “If my home isn’t in a flood zone, why should I buy flood insurance?” Floods are the most common natural disaster in the United States, and unfortunately the flood zone is often underestimated. Floodplain maps are generally created based on different data sources, such as communities’ knowledge and observations, flood models, and remote sensing observations. In recent decades, remote sensing observations have greatly improved our ability to capture historical inundation extents and produce elevation, which is a key input for flooding modeling. However, there are often not enough observations for various reasons, such as missing local-scale flooding events and the flow peak caused by poor spatiotemporal resolution, which can lead to underestimating the flood zone.

What is your favorite part of research? 

I enjoy going out and doing field-work. My favorite site was the Tanana River in Alaska, the most incredible place I’ve ever been. In the summer of 2021, I went there with a team of scientists to do a shoreline survey and UAV photography of a river sandbar, measure suspended sediment, and capture cross river profile with an Acoustic Doppler Current Profiler (ADCP) to measure the velocity and direction of the water throughout the water column to estimate river discharge. I had never crossed a river perpendicular to the shoreline in a small boat or seen the water flowing so wildly downstream. Even experienced boaters can make mistakes while navigating and hit hidden sandbars. The shoreline landscape along the river is amazing, especially when viewing it from inside a fast moving boat. I also participated in a shoreline survey, walking with two scientists with survey-grade GPS, learning about wildfires, rivers, fish, and even bears.

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