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Observed changes in false springs over the contiguous United States

TitleObserved changes in false springs over the contiguous United States
Publication TypeJournal Article
Year of Publication2014
AuthorsPeterson, AG, Abatzoglou, JT
JournalGeophysical Research Letters
Page range2156–2162
Date Published03/2014

Abstract Climate warming fosters an earlier spring green-up that may bring potential benefits to
agricultural systems. However, advances in green-up timing may leave early stage vegetation growth
vulnerable to cold damage when hard freezes follow green-up resulting in a false spring. Spatiotemporal
patterns of green-up dates, last spring freezes, and false springs were examined across the contiguous
United States from 1920 to 2013. Results indicate widespread earlier green-up and last spring freeze dates over
the period. Observed changes in these dates were asymmetric with the last spring freeze date advancing to
earlier in the year relative to green-up date. Although regionally variable, these changes resulted in a reduction
in false springs, notably over the past 20 years, except across the intermountain western United States where
the advance in green-up timing outpaced that of the last spring freeze. A sensitivity experiment shows that
observed decreases in false springs are consistent with a warming climate.

Geophysical Research Letters