What is a ‘vernal window’?
With the first day of spring around the corner, temperatures start to rise, ice melts away, and the world around us starts to blossom. Scientists refer to this transition from winter to the growing season as the “vernal window”, and a new study led by the University of New Hampshire, U.S., shows this window may be getting longer.
“Historically, the transition into spring is comparatively shorter than other seasons,” says Alexandra Contosta, a research assistant professor at the University of New Hampshire’s Earth Systems Research Center. “You have snow melting and lots of water moving through aquatic systems, nutrients flushing through that water, soils warming up, and buds breaking on trees. Something striking happens after a very cold winter or when there’s been a lot of snow. Things seem to wake up all together, which is why spring seems to happen so quickly and can feel so dramatic.”
However, research shows that the extent of snow cover over the Northern Hemisphere has declined significantly in the past 30 years. Climate change is altering the timing and duration of the vernal window.
