Observing Large-Scale Vegetation Response to Rainfall Variability
Andrew Feldman
NASA Goddard Space Flight Center
Monday December 1, 2025, 12 PM ET
In-Person Seminar Info:
This seminar will be held at noon at Rm 4102 of ESSIC, 5825 University Research Ct. College Park, MD 20740. Refreshments will be available for those who attend in person, and a Zoom option is also available for virtual attendees.
Click here to RSVP for attendance
Abstract:
Vegetation directly influences global water, carbon, and energy cycles by regulating fluxes between the surface and lower atmosphere. There is therefore a need to understand vegetation functioning (e.g., photosynthesis, transpiration) response to climate forcing and feedbacks on the atmosphere. To a first order, it is well understood where vegetation is limited by water, temperature, and/or light globally at seasonal timescales. However, in practice, vegetation functioning is highly spatiotemporally variable due to a range of factors; even in dry locations, the total water availability year to year only explains a fraction of the vegetation functioning variability. Here, I evaluate vegetation responses to two sources of less-explored variability: daily rainfall intermittency (rainfall pulses and dry spell dynamics) as well as sub-seasonal scale droughts. I ask: what are the spatial patterns for how vegetation responds to rainfall variability and extremes? First, I present a global study that evaluates vegetation sensitivity to effects of daily rainfall variability. We find that satellite-based vegetation indices are sensitive to daily rainfall variability across 42 percent of the vegetated land surfaces, and follow moisture gradients in their signs of responses. Second, I present results from a NASA ECOSTRESS study evaluating gradients of ecosystem sensitivity to drought. We find that there is a tendency for drier ecosystems to have higher drought sensitivities, but with large spatial variability of responses. Ultimately, these results highlight the complexity of vegetation functioning and coupling with the atmosphere under moisture variability at sub-seasonal timescales. Furthermore, these rainfall variability features are only becoming more variable.
Biosketch:
Andrew is an associate research scientist in the Biospheric Sciences Laboratory at NASA Goddard Space Flight Center and research faculty at University of Maryland ESSIC in Maryland, USA. His main goal is to understand how environmental variability and extremes influence global plant function and evaporation, and the consequent global water cycle responses. Drylands, such as in the western U.S., are a large focus of his work. He is currently a member of the NASA ECOSTRESS Science Team and co-lead of the proposed NASA Adaptation and Response in Drylands (ARID) dryland field campaign. Andrew received his Ph.D. from Massachusetts Institute of Technology in 2021 in Civil and Environmental Engineering. In 2016, he graduated from Drexel University with B.S. and M.S. degrees in Civil Engineering. Andrew was formerly a NASA Postdoctoral Program Fellow.
Hybrid (In-Person & Virtual):
This is a hybrid (in-person & virtual) seminar with refreshments served at Rm 4102, 5825 University Ct, MD
Event site: https://go.umd.edu/feldman
Zoom Webinar: https://go.umd.edu/essicseminarwebinars
Zoom Meeting ID: 918 7733 3086
Zoom password: essic
US Toll: +13017158592
Global call-in numbers: https://umd.zoom.us/u/aMElEpvNu
For IT assistance:
Cazzy Medley: cazzy@umd.edu
Resources:
Seminar schedule & archive: https://go.umd.edu/essicseminar
Seminar Google calendar: https://go.umd.edu/essicseminarcalendar
Seminar recordings on Youtube: https://www.youtube.com/user/ESSICUMD
