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Natural Science Seminar: Patterns, Sources, & Impacts of Variations and Trends in the Timing of Seasonal Transitions Over the Coterminous U.S.

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Come join us for the this week's Natural Science Seminar:

Patterns, Sources & Impacts of Variations and Trends in the Timing of Seasonal Transitions Over the Coterminous U.S.


Friday, October 27th


Science 147


Presented by:  Dr. Julio Betancourt, USGS

Dr. Julio Betancourt will show how day-of-year [DOY] metrics can define spring onset in the CONUS. These DOY metrics exhibit secular trends consistent with both natural variability and greenhouse warming. In the atmosphere, spring onset variations also appear linked to the Pacific North American (PNA) pattern and the Northern Annular Mode (NAM). By contrast, last spring frost, first fall frost, and the duration of the growing season in CONUS poorly tracks common climatic indices, and instead is modulated by the polar vortex. 

Seasonal timing has myriad impacts on plants and animals, biospheric processes, and human systems, and is critical for formulating adaptive responses to both climate variability and change. In the coterminous U.S. [CONUS], the timing of seasonal transitions varies widely from year to year and is also changing directionally, yet the climatic drivers, patterns, and consequences of these variations are not well understood. In his presentation, Betancourt will discuss different interpretations of large-scale drivers, opportunities for long-range forecasting, and implications for continental-scale phenological monitoring in the U.S.

Julio Betancourt is a Senior Scientist with the USGS in Reston VA, and also served for three decades as an Adjunct Professor at the University of Arizona, where he received his Ph.D. in Geosciences with a minor in Ecology & Evolutionary Biology.  He is a research hydrologist and ecologist who studies how climate variability and change affects terrestrial ecosystems at scales critical for understanding ecological and evolutionary processes and informing rational approaches to managing water and other natural resources. A Fellow of the American Geophysical Union and founding co-chair of the USGS Council of Senior Science Advisors, Dr. Betancourt has published two books and 180 peer-reviewed technical papers on a wide diversity of topics.  He has received honors from the American Water Resources Association, the Ecological Society of America and the Geological Society of America, and top awards from the U.S. Department of the Interior and the White House.  He is the founder of   and established the Southern Arizona Buffelgrass Coordination Center, an NGO that coordinates assessment and mitigation of an African grass invasion in the Sonoran Desert.





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