University of Arizona
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Archived Extended Spring Indices Average and Anomaly Products (1981-2010 climate normal)

posted on 2022-02-22, 16:53 authored by USA National Phenology Network
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: Extended Spring Indices, Continental United States, 1981 - Current Year

For inquiries regarding the contents of this dataset, please contact the Corresponding Author listed in the README.txt file. Administrative inquiries (e.g., removal requests, trouble downloading, etc.) can be directed to