TY - JOUR
T1 - Biologically-Relevant Trends in Springtime Temperatures Across the United States
AU - Crimmins, Theresa M.
AU - Crimmins, Michael A.
N1 - Funding Information:
The mean DOY (1981–2010) 50‐, 250‐, and 450‐GDD threshold DOY layers calculated in this analysis are available from the Dryad Digital Repository: https://doi.org/10.5061/dryad.pp045j3 . The authors declare no conflicts of interest. We thank Rey Granillo and Leland Boeman, University of Arizona Institute for the Environment, for computing resources used in this study. Computing resources provided by CyVerse were also utilized in this study (National Science Foundation under Award Numbers DBI‐0735191 and DBI‐1265383), www.cyverse.org . This work was supported in party by the National Oceanic and Atmospheric Administration's Regional Integrated Sciences and Assessments (RISA) program through grant NA17OAR4310288 with the Climate Assessment for the Southwest program at the University of Arizona.
Funding Information:
The mean DOY (1981?2010) 50-, 250-, and 450-GDD threshold DOY layers calculated in this analysis are available from the Dryad Digital Repository: https://doi.org/10.5061/dryad.pp045j3. The authors declare no conflicts of interest. We thank Rey Granillo and Leland Boeman, University of Arizona Institute for the Environment, for computing resources used in this study. Computing resources provided by CyVerse were also utilized in this study (National Science Foundation under Award Numbers DBI-0735191 and DBI-1265383), www.cyverse.org. This work was supported in party by the National Oceanic and Atmospheric Administration's Regional Integrated Sciences and Assessments (RISA) program through grant NA17OAR4310288 with the Climate Assessment for the Southwest program at the University of Arizona.
Publisher Copyright:
©2019. American Geophysical Union. All Rights Reserved.
PY - 2019/11/16
Y1 - 2019/11/16
N2 - Long-term trends in temperature—a primary driver of phenology—are typically evaluated using monthly or seasonal averages. However, accumulated warmth, rather than average temperature, cues phenological events; further, the amount of heat necessary to trigger activity is species-specific. We evaluated trends in the timing of three heat accumulation thresholds encompassing spring-season biological activity in the conterminous United States over a 70-year period to document changes from a biologically relevant perspective. The Southwest, Northeast, and Northwest regions exhibit the strongest advancements. Rates of change vary among thresholds within many regions, resulting in temporal compression and lengthening within the season. Further, in the Eastern United States, the days between when a single threshold is met in the south and north are decreasing; in the West, the opposite pattern is occurring. These trends generally match long-term observations of species' phenology, underscoring the value of this approach for documenting biologically relevant changes in temperature.
AB - Long-term trends in temperature—a primary driver of phenology—are typically evaluated using monthly or seasonal averages. However, accumulated warmth, rather than average temperature, cues phenological events; further, the amount of heat necessary to trigger activity is species-specific. We evaluated trends in the timing of three heat accumulation thresholds encompassing spring-season biological activity in the conterminous United States over a 70-year period to document changes from a biologically relevant perspective. The Southwest, Northeast, and Northwest regions exhibit the strongest advancements. Rates of change vary among thresholds within many regions, resulting in temporal compression and lengthening within the season. Further, in the Eastern United States, the days between when a single threshold is met in the south and north are decreasing; in the West, the opposite pattern is occurring. These trends generally match long-term observations of species' phenology, underscoring the value of this approach for documenting biologically relevant changes in temperature.
KW - growing degree days
KW - phenology
KW - spring season
KW - thresholds
KW - trends
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U2 - 10.1029/2019GL085251
DO - 10.1029/2019GL085251
M3 - Article
AN - SCOPUS:85074834431
SN - 0094-8276
VL - 46
SP - 12377
EP - 12387
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 21
ER -