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# Archived Extended Spring Indices Average and Anomaly Products (1981-2010 climate normal)

Preferred citation (DataCite format):

  USA National Phenology Network (2022).
  Archived Extended Spring Indices Average and Anomaly Products (1981-2010 climate normal).
  University of Arizona Research Data Repository.
  Dataset. https://doi.org/10.25422/azu.data.19067576


Corresponding Author:
  Alyssa H Rosemartin, USA National Phenology Network/SNRE, ahouse@email.arizona.edu


License:
  CC BY 4.0


DOI:
  https://doi.org/10.25422/azu.data.19067576



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## Summary

The Extended Spring Indices are mathematical models that predict the "start of
spring" (timing of leaf out or bloom for species active in early spring) at a
particular location. The USA National Phenology Network (USA-NPN) hosts a
suite of gridded Extended Spring Indices products. In 2022, the USA NPN
updated all long-term average and anomaly products in this suite to use the
more recent climate normal period (1991-2020).

This record contains the archived layers that use the prior normal
(1981-2010). The data consists of geotiff rasters with leaf out and bloom
dates. The "average" files give leaf and bloom dates as day of year, averaged
for the period 1981-2010. The "anomaly" files show for each year 1981-2021,
the difference between that year's leaf out or bloom date and the long term
average.

The products using updated normals can be accessed here:
https://arizona.figshare.com/articles/dataset/Extended_Spring_Indices_Continental_United_States_1981_-_Current_Year/14270627  



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## Files and Folders

The spring_index.zip contains three subfolders:

1) avg_spring_index, which contains the rasters for long-term average leaf and bloom dates (there are subfolders for 2-kilometer resolution leaf, 2-kilometer resolution bloom, 4-kilometer resolution leaf and 4-kilometer resolution bloom).

2) spring_index_anomaly which contains the annual anomalies for National Centers for Environmental Prediction (NCEP) (called "historic", for the period 2016-2021) leaf and bloom, as well as PRISM (for the period 1981-2020) leaf and bloom.

3) spring_index_return_interval which contains the leaf and bloom return intervals for 2020 and 2021 based on the 1981-2010 normal period. Return interval products show the frequency with which a given pixel experiences a spring as early (or late) as the current spring.



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## Materials & Methods

Please see the USA National Phenology Network gridded products documentation report for full details on the development of this data product:

Crimmins, T.M., Marsh, R.L., Switzer, J.R., Crimmins, M.A., Gerst, K.L., Rosemartin, A.H., and Weltzin, J.F., 2017, USA National Phenology Network gridded products documentation: U.S. Geological Survey Open-File Report 2017–1003, 27 p., https://doi.org/10.3133/ofr20171003. 



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## Contributor Roles

The roles are defined by the CRediT taxonomy http://credit.niso.org/

  - Michael Crimmins, University of Arizona, Conceptualization, Data Curation, Methodology, Visualization
  - Theresa Crimmins, University of Arizona, Conceptualization, Data Curation, Methodology, Visualization
  - Katharine Gerst, University of Arizona, Conceptualization, Data Curation, Methodology, Visualization
  - Lee Marsh, University of Arizona, Conceptualization, Data Curation, Methodology, Visualization
  - Alyssa Rosemartin, University of Arizona, Conceptualization, Data Curation, Methodology, Visualization
  - Jeff Switzer, University of Arizona, Conceptualization, Data Curation, Methodology, Visualization
  - Jake Weltzin, US Geological Survey, Conceptualization, Data Curation, Methodology, Visualization

 

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## Additional Notes 

Links: 
  - https://doi.org/10.25422/azu.data.14270627