DOI: 10.5061/dryad.m0cfxppck
title: Data from: Gross primary productivity from leaf-age-dependent light use efficiency (LA-LUE) model over pantropical evergreen broadleaved forests

description: Tropical and subtropical evergreen broadleaved forests (TEFs) contribute
 more than one-third of terrestrial gross primary productivity (GPP).
 However, the continental-scale leaf phenology-photosynthesis nexus over
 TEFs is still poorly understood to date. This knowledge gap hinders most
 light use efficiency (LUE) models from accurately simulating the GPP
 seasonality in TEFs. Leaf age is the crucial plant trait to link the
 dynamics of leaf phenology with GPP seasonality. Thus, here we
 incorporated the seasonal leaf area index (LAI) of different leaf age
 cohorts into a widely-used LUE model (i.e., EC-LUE) and proposed a novel
 leaf-age-dependent LUE model (denoted as LA-LUE model). At the site level,
 the LA-LUE model (average R2 = 0.59, average RMSE = 1.23 gC m−2 d−1)
 performs better than the EC-LUE model in simulating the GPP seasonality
 across the nine TEFs sites (average R2 = 0.18; average RMSE = 1.87 gC m-2
 d-1). At the continental scale, the monthly GPP estimates from the LA-LUE
 model are consistent with FLUXCOM GPP data (R2 = 0.80; average RMSE = 1.74
 gC m-2 d-1), and satellite-based GPP data retrieved from the global
 Orbiting Carbon Observatory-2 (OCO-2) based solar-induced chlorophyll
 fluorescence (SIF) product (GOSIF) (R2 = 0.64; average RMSE = 1.90 gC m-2
 d-1) and the reconstructed TROPOspheric Monitoring Instrument SIF dataset
 using machine learning algorithms (RTSIF) (R2 = 0.78; average RMSE = 1.88
 gC m-2 d-1). Typically, the estimated monthly GPP not only successfully
 represents the unimodal GPP seasonality near the Tropics of Cancer and
 Capricorn, but also captures well the bimodal GPP seasonality near the
 Equator. Overall, this study for the first time integrates the leaf age
 information into the satellite-based LUE model and provides a feasible
 implementation for mapping the continental-scale GPP seasonality over the
 entire TEFs.
description: On the basis of the theory of light use efficiency, the LA-LUE
 model was proposed by incorporating the seasonal leaf area index (LAI) of
 different leaf age cohorts into the EC-LUE (Eddy Covariance – Light Use
 Efficiency) model. To do this, three LAI cohorts (i.e.,
 LAI<sub>young</sub>, LAI<sub>mature</sub>, and
 LAI<sub>old</sub>) were introduced to reconstruct the dynamic
 maximum light use efficiency (ε<sub>max</sub>) and absorbed
 photosynthetically active radiation (APAR) for young leaves, mature
 leaves, and old leaves. After that, the product of
 ε<sub>max</sub> and APAR of sunlit and shaded leaves were
 accumulated to each leaf age cohort, respectively, and then to simulate
 the total GPP. It utilizes a new leaf-age-dependent leaf area index
 (Lad-LAI) product in combination with ERA5 air temperature, dew
 temperature, and mean surface downward short-wave radiation flux data and
 NOAA Earth System Research Laboratories CO<sub>2</sub>
 concentration product to produce a coherent seasonal data record of GPP
 over pantropical evergreen broadleaved forests. The mapped extent is
 longitude (-180, 180) and latitude (-30, 30). Unit: gC
 m<sup>-2</sup> month<sup>-1</sup>; Fill value:
 -1.
description: # Gross primary productivity from leaf-age-dependent light use efficiency
 (LA-LUE) model over pantropical evergreen broadleaved forests
 [https://doi.org/10.5061/dryad.m0cfxppck](https://doi.org/10.5061/dryad.m0cfxppck) ## Description of the data and file structure This dataset mainly contains monthly temporal resolution, 0.25° × 0.25° spatial resolution gross primary productivity (GPP) estimation from leaf-age-dependent light use efficiency model (LA-LUE) over pantropical evergreen broadleaved forests during 2001-2018. The mapped extent is longitude (-180, 180) and latitude (-30, 30). The MatLab code LALUE_Model.m and Parameters.txt contain the information to create the LA-LUE GPP dataset.  ## Sharing/Access information The leaf-age-dependent leaf area index data are available from [https://doi.org/10.6084/m9.figshare.21700955.v4](https://doi.org/10.6084/m9.figshare.21700955.v4) ## **Code/Software** The LA-LUE GPP dataset was obtained by MatLab R2023b and stored in .tif file format. ## **Version changes** 31-July-2024: Added the unit and fill value of the dataset. Updated the code, which was confusing due to the typing errors.