Changes in the Timing of Spring

First leaf indices averaged over 1981-2010 (e.g., the start of spring) across the United States. March 2012 first leafs plotted below and are nearly 3σ earlier than normal. Figure from (Labe et. al., 2015, submitted).

The onset of spring is important for the dynamics of the Earth system and a variety of ecological sectors. Understanding changes in the timing and frequency of anomalously early springs will be necessary for evaluating the climate system in response to natural and anthropogenic forcings. We focus on the dynamics and changes in spring onset through historical and future periods using a variety of observational and modeling experiments.

Working under the supervision of Dr. Toby Ault at Cornell University, our most recent project uses the CESM Large Ensemble (LENS) project^[1] and Extend Spring Indices Model (SI-x)^[2] to understand the risk of March 2012-like (earliest spring in observational record^[3]) springs through the end of the 21^st century. Our findings suggest that the forced warming in response to climate change will make the frequency of March 2012-like springs the new normal by mid century [Labe et al., 2016].

Refereed/Peer-Reviewed Publications:

[1] Labe, Z.M., T.R. Ault, and R. Zurita-Milla (2016), Identifying Anomalously Early Spring Onsets in the CESM Large Ensemble Project, R. Clim Dyn, DOI:10.1007/s00382-016-3313-2
[HTML] [PDF] [BibTeX][Code]
[Cornell Press Release][The Cornell Daily Sun][Earther][National Phenology Network]

Non-refereed/Other Publications:

[1] Labe, Z.M., April 2015: Anomalously Early Onset of Spring in the CESM Large Ensemble. Cornell University. Undergraduate Honors Thesis.
[PDF]

Conferences/Presentations:

[2] Labe, Z.M. Climate change extremes by season in the United States, Hershey Horticulture Society, Hershey, PA (Sep 2023).

[1] Labe, Z.M. and T.R. Ault. Anomalously Early Onset of Spring in the CESM Large Ensemble Project, 95th American Meteorological Society Annual Meeting, Phoenix, AZ (Jan 2015).
[Abstract] [Poster]