Modeling Photosynthetically Active Radiation from Satellite-Derived Estimations over Mainland Spain

Jose Vindel,José Souto,Ramón Méndez-Gómez,Abel Paz-Gallardo,Ana Navarro,Juan Casares,David Cartelle,Rita Valenzuela,Luis Zarzalejo

doi:10.3390/rs10060849

Abstract

A model based on the known high correlation between photosynthetically active radiation (PAR) and global horizontal irradiance (GHI) was implemented to estimate PAR from GHI measurements in this present study. The model has been developed using satellite-derived GHI and PAR estimations. Both variables can be estimated using Kato bands, provided by Satellite Application Facility on Climate Monitoring (CM-SAF), and its ratio may be used as the variable of interest in order to obtain the model. The study area, which was located in mainland Spain, has been split by cluster analysis into regions with similar behavior, according to this ratio. In each of these regions, a regression model estimating PAR from GHI has been developed. According to the analysis, two regions are distinguished in the study area. These regions belong to the two climates dominating the territory: an Oceanic climate on the northern edge; and a Mediterranean climate with hot summer in the rest of the study area. The models obtained for each region have been checked against the ground measurements, providing correlograms with determination coefficients higher than 0.99.

Highlights

Active radiation (PAR) is radiation with wavelengths of 400–700 nm in the solar spectrum
Rubio et al [10] estimated global horizontal irradiance (GHI) from a satellite, before Photosynthetically active radiation (PAR) was obtained using an empirical model proposed by Alados-Arboledas et al [11], which was developed from a database located at Almería
A model based on the known linear relationship between GHI and PAR was implemented to estimate PAR from GHI measurements in this present study

Summary

Introduction

Active radiation (PAR) is radiation with wavelengths of 400–700 nm in the solar spectrum. PAR measurement stations are very scarce and, usually it is estimated from empirical expressions relating it to solar global irradiance [1,2,3,4,5,6,7], which is measured more frequently. PAR estimations can be obtained from satellites. Rubio et al [10] estimated global horizontal irradiance (GHI) from a satellite, before PAR was obtained using an empirical model proposed by Alados-Arboledas et al [11], which was developed from a database located at Almería. Kato bands are 32 bands of different widths which the solar spectrum can be divided into. In each of those bands, the absorption coefficient of different gases is almost constant

Methods

Results

Conclusion