GPP-CO2

Overview

This repository contains analysis and plotting scripts to reproduce the emergent constraint results presented in:

Keenan et al. 2021: A constraint on historic growth in global photosynthesis due to increasing CO2.
Nature - https://www.nature.com/articles/s41586-021-04096-9

Full information on the methods used in this study are attached to this paper and are available online at the link provided above; this includes information about datasets used, as well as the motivation and reasoning behind the analysis.

The scripts, written in Matlab, are:

A. varianceNormalization.m

This script derives the relationship between Sland and Beta^{GPP}, and performs variance normalization to extract the partial response.

B. calc_EC_andPlot.m

This code, called by 'varianceNormalization.m' uses the emergent constraint between the partial response of Sland to Beta^{GPP} across models to derive the constrained Beta^{GPP}

Running the code

Running A_varianceNormalization.m will produce the following figures reported in Keenan et al. 2021:
*Figure 1a-d
*ED Figure 1
*ED Figure 2
*ED Figure 3
*ED Figure 6

A_varianceNormalization.m calls B_calc_EC_andPlot.m

Folder structure and contents

./figures/emergent contains the figures produced if the save_figures flag is set to 1.

./TRENDYv6_derived contains derived output from the TRENDY model simulations. TRENDY model simulations are not publically available but can be obtained through request to Prof. Sitch (S.A.Sitch@exeter.ac.uk)

./dataIntermediates contains output from the scripts included here, extracted from the data contained in ./TRENDYv6_derived