AOSC Seminar by Dr. Rong Fu, 09/18/2025
AOSC Seminar
Rong Fu
UCLA, Atmospheric and Oceanic Sciences
Title
Attributing intensified fire weather and droughts in the Western United States with an observation-based machine learning approach
Abstract
Droughts and wildfires have long been integral components of the natural climate and ecosystems of the Western United States. However, both hazards have intensified rapidly in recent decades. The region has experienced the most severe mega-drought of the past millennium and a rapid increase in burned area since the early 21st century. While these trends are broadly attributable to anthropogenic warming and the associated rise in atmospheric moisture demand, the relative contributions of natural climate variability versus human-induced climate change to the observed intensification of droughts and wildfires have remained unclear previously.
To address this question, we applied an ensemble-analogue approach to disentangle the influence of anomalous atmospheric circulation, which is mainly driven by natural climate variability, on drought severity and fire weather intensity, from the influence of changing thermodynamic conditions primarily driven by surface warming. Our results show that warming-induced increases in moisture demand account for at least 75% of the rise in fire weather intensity, as measured by vapor pressure deficit (VPD), and nearly 90% of the increase in drought severity and spatial extent across the Western United States since 2000. In fact, elevated evaporative demand has now surpassed precipitation deficits as the dominant contributor to drought severity and extent.
These findings highlight that anthropogenic forcing is the primary driver behind the intensification of fire weather and the ongoing mega-drought over the Western United States in the 21st century.
Bio
Rong Fu is a professor in the Department of Atmospheric and Oceanic Sciences, the director of the Joint Institute of Regional Earth System Science and Engineering in University of California, Los Angeles. Her research focuses on the mechanisms that control droughts, fire weather, rainfall seasonality and variability over Amazonian and North American regions. She received NSF CAREER and NASA New Investigator Awards, and the American Meteorological Society (AMS) Outstanding Achievement Award for biometeorology. She is an elected member of National Academy of Engineering (NAE), and also an elected fellow of the AMS, the American Geophysical Union (AGU), and the American Association For the Advancement of Science (AAAS), respectively. She served as the President of the Global Environmental Change Section (2015-2016) and Leadership Team of the AGU Council, and the Chair of the AAAS Atmosphere and Hydrosphere (2022), and a member of AAAS Council and its Executive Committee (2023). She is also a current AMS Council Member. She has served on many national and international panels and co-led NOAA Drought Task Force IV. She also serves as an Editor of Journal of Geophysical Research – Atmosphere, and the Vice Chair of NAE Exploratory Search Committee.
Contact
If you are not subscribed to seminar announcements and need a link to this online seminar please contact aosc-helper. You can also subscribe to weekly links and announcements below.
AOSC Seminar
Pre-seminar refreshment: N/A
Seminar: 3:30-4:30pm, Room: ATL 2400(only when in-person)
Meet-the-Speaker: 4:30-5:00pm, Room: ATL 3400(only when in-person) [For AOSC Students only]
[ Subscribe to receive seminar announcements | Email aosc-deptseminar@umd.edu to give a seminar ]