What is it about?

Indices that measure the duration of the Growing Season using temperature data are widely available. These are often based on the difference in timing between spring onset and autumn onset. We demonstrate that conventional indices, such as the index defined by the Expert Team on Climate Change Detection and Indices (ETCCDI, http://etccdi.pacificclimate.org/), are vulnerable to weather-related noise that gives an unrealistic impression of the true length of the growing season. By using a more realistic definition of the growing season length we are able to demonstrate a coherent increase in the length of the growing season at a rate of five days per decade over the last 50 years across Europe. Superimposed on this trend are year-to-year variations that are closely linked to variations in hemispheric-scale wind patterns.

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Why is it important?

Knowledge about how the length of the growing season has changed over the past and is likely to change in the future due to global warming is of paramount importance to regional and global economies. By defining a more realistic measure of the growing season we are able to remove some of the uncertainty in these changes.


The indices of the growing season used in this analysis are based purely on temperature observations across Europe, and are intended to give a measure of the growing season that is broadly applicable to many types of vegetation and crops. While our refined index is more realistic from the perspective of atmospheric dynamics, our analysis does not provide a detailed comparison against phenological data. As such we hope to stimulate further research that compares our index against measured pheno-phase indicators, such as the length of the observed growing season in different vegetation types.

Dr Richard Cornes
National Oceanography Centre

Read the Original

This page is a summary of: A Reappraisal of the Thermal Growing Season Length across Europe, International Journal of Climatology, October 2018, Wiley, DOI: 10.1002/joc.5913.
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