TY - JOUR
T1 - Does an Early Spring Indicate an Early Summer? Relationships Between Intraseasonal Growing Degree Day Thresholds
AU - Crimmins, M. A.
AU - Crimmins, T. M.
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 the staff of the USA National Phenology Network National Coordinating Office for inspiring this line of inquiry. 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. We also 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 awards DBI-0735191 and DBI-1265383; www.cyverse.org). Staghorn sumac and strawberry phenology observational data were provided by the USA National Phenology Network and the many participants who contribute to its Nature's Notebook program. Finally, we thank two anonymous reviewers and the Associate Editor for their constructive comments that helped improve this manuscript.
Publisher Copyright:
©2019. American Geophysical Union. All Rights Reserved.
PY - 2019/8/1
Y1 - 2019/8/1
N2 - Spring heat accumulation plays a major role in the timing of events such as leaf-out, leaf expansion, flowering, and insect hatch in temperate systems. Accordingly, heat accumulation can serve as a proxy for the timing of plant and insect phenological activity and can be used in a predictive way when the timing of heat accumulation thresholds being reached can be anticipated. This has strong value for a host of planning and management applications. If relationships exist between earlier- and later-season thresholds at a location, then the timing of later-season phenological events that are forced by the accumulation of warmth could be anticipated based on when earlier-season thresholds are met. Using high-resolution daily temperature data, we calculated the coherence in pairs of spring-season heat accumulation (growing degree day) threshold anomalies over 1948–2016. Overall, relationships between thresholds spanning the entire spring season were relatively low, while later season thresholds exhibited much higher correlations. This pattern is generally the result of decreasing variability in heat accumulation with season progression. However, correlation strengths did not follow latitudinal or gradients, revealing that within-season heat accumulation and interannual variability in threshold timing are unique to the specified base temperature and thresholds being compared. We show that the relationships between earlier- and later-season heat accumulation thresholds were sufficient to accurately predict the timing of phenological events in plants in two case examples.
AB - Spring heat accumulation plays a major role in the timing of events such as leaf-out, leaf expansion, flowering, and insect hatch in temperate systems. Accordingly, heat accumulation can serve as a proxy for the timing of plant and insect phenological activity and can be used in a predictive way when the timing of heat accumulation thresholds being reached can be anticipated. This has strong value for a host of planning and management applications. If relationships exist between earlier- and later-season thresholds at a location, then the timing of later-season phenological events that are forced by the accumulation of warmth could be anticipated based on when earlier-season thresholds are met. Using high-resolution daily temperature data, we calculated the coherence in pairs of spring-season heat accumulation (growing degree day) threshold anomalies over 1948–2016. Overall, relationships between thresholds spanning the entire spring season were relatively low, while later season thresholds exhibited much higher correlations. This pattern is generally the result of decreasing variability in heat accumulation with season progression. However, correlation strengths did not follow latitudinal or gradients, revealing that within-season heat accumulation and interannual variability in threshold timing are unique to the specified base temperature and thresholds being compared. We show that the relationships between earlier- and later-season heat accumulation thresholds were sufficient to accurately predict the timing of phenological events in plants in two case examples.
KW - ecological forecasting
KW - growing degree days
KW - seasonality
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U2 - 10.1029/2019JG005297
DO - 10.1029/2019JG005297
M3 - Article
AN - SCOPUS:85071418716
SN - 2169-8953
VL - 124
SP - 2628
EP - 2641
JO - Journal of Geophysical Research: Biogeosciences
JF - Journal of Geophysical Research: Biogeosciences
IS - 8
ER -