The Challenge of Predicting Rainfall in a Changing Climate

School of Earth and Atmospheric Sciences’ Jie He wins NSF CAREER grant to work on new methods to unlock the uncertainty in rainfall predictions

July 14, 2021

An assistant professor in the School of Earth and Atmospheric Sciences will have funding for the next five years to study a problem that's frequently on the minds of many climate scientists: How will rainfall change as the Earth’s surface continues to heat?

Jie He has received an $854,000 National Science Foundation (NSF) CAREER Award for his project, “Hydrological Sensitivity Across Timescales”. The NSF annually presents the awards to early-career scientists “who have the potential to serve as academic role models in research and education and to lead advances in the mission of their department or organization,” according to the NSF website. “Activities pursued by early-career faculty should build a firm foundation for a lifetime of leadership in integrating education and research.”

“It felt nice to get the award,” He says. “Some of the senior faculty members at EAS had been mentoring me and guiding me on proposal writing, so I felt it's somehow a way to show my appreciation. Because it's a five-year grant, I feel very fortunate to be able to lead a project I care about, and to work on it for a sustained period of time.”

As greenhouse gas concentrations keep rising, the Earth’s surface will continue to warm, and the amount of rainfall is expected to change substantially. Predicting how rainfall will change is of great importance for preparing adaptation and mitigation plans, He says. 

“Predictions of long-term rainfall changes rely predominantly on simulations of climate models. However, current models disagree on many aspects of rainfall changes, which greatly undermines the usefulness of rainfall predictions,” He adds. Because observations are generally too short to be used to directly infer long-term rainfall changes, constraining model predictions has been a great challenge. Fortunately, there are abundant observations of short-term (annual or monthly) rainfall variations. These observations allow scientists to study mechanisms of rain, some of which operate at both short and long timescales. 

He has identified several aspects of long-term rainfall changes that are fundamentally tied to how rainfall responds to short-term surface temperature variations. “Based on such relationships, I will evaluate long-term rainfall predictions from climate models by using observed short-term rainfall variations. This work will yield a better understanding of the uncertainty in rainfall predictions and will identify key processes of which observational constraints are available to improve models.”

He will then apply this method to a state-of-the-art global climate model, where the identified observational constraints will be used to improve model parameters and ultimately, its prediction of future rainfall changes.

“By understanding mechanisms of rainfall changes and causes of prediction uncertainties, this project will identify key processes that require observational validation to improve model predictions. Such an improvement will ultimately help society to cope better with climate variations.”

The educational component of He’s project involves the teaching and application of climate models at graduate, undergraduate, and high school levels. Specifically, He will create a hands-on climate modeling course for graduate students in climate science, design a climate science and modeling module that can be incorporated into high school science curriculum, and train undergraduate students to conduct and analyze climate model experiments via the summer Research Experiences for Undergraduates (REU) Program.

Jie He joined Georgia Tech in 2018 and is the principal investigator of the Climate Dynamics and Modeling lab group, which seeks to uncover the mechanisms of climate change and variability. Using simple and comprehensive numerical models as the primary tools, the group works at the interface of physics, mathematics, and computer sciences. Its research ranges from atmospheric dynamics and hydroclimate, to air-sea interaction and ocean heat uptake.



About the National Science Foundation

The National Science Foundation (NSF) is an independent federal agency created by Congress in 1950 "to promote the progress of science; to advance the national health, prosperity, and welfare; to secure the national defense..." NSF is vital because it supports basic research and people to create knowledge that transforms the future. This type of support is a primary driver of the U.S. economy, enhances the nation's security, and advances knowledge to sustain global leadership. 

With an annual budget of $8.5 billion (FY 2021), NSF is the funding source for approximately 25 percent of all federally supported basic research conducted by America's colleges and universities. In many fields such as mathematics, computer science and the social sciences, NSF is the major source of federal backing.

About the College of Sciences at Georgia Tech

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Renay San Miguel
Communications Officer II/Science Writer
College of Sciences