RT info:eu-repo/semantics/article T1 Validation and calibration of models to estimate photosynthetically active radiation considering different time scales and sky conditions A1 Blas Corral, Marian de A1 García Rodríguez, Ana A1 García Ruiz, Ignacio A1 Torres Escribano, José Luis K1 Photosynthetically active radiation K1 Solar irradiance K1 Sky types K1 Model calibration K1 Ingeniería eléctrica K1 Electric engineering AB Photosynthetically Active Radiation (PAR) is a fundamental parameter for developing plant productivity models. Nevertheless,instrumentation for measuring PAR and to record it is scarce at conventional meteorological stations. Several procedures have thereforebeen proposed for PAR estimation. In this work, 21 previously published analytical models that correlate PAR with easily availablemeteorological parameters are collected. Although longer time scales were considered in the original publications, a minute rangewas applied in this work to calibrate the PAR models. In total, more than 10 million input records were gathered from the SURFRADstation network from a 10-year long time series with data frequencies recorded every 1 min. The models were calibrated both globally,using data from all stations and locally, with data from each station. After calibration, the models were validated for minute, hourly anddaily data, obtaining low fitting errors at the different stations in all cases, both when using the globally calibrated models and with themodels calibrated for each location. Although the PAR results in general improved for locally calibrated models, the use of local modelsis not justified, since the global models presented offered very satisfactory PAR results for the different climatic conditions where themeteorological stations are located. Thus, PAR estimation model should then be selected, solely considering the meteorological variablesavailable at the specific location. When applying the globally calibrated models to input data classified according to sky conditions (fromclear to overcast), the PAR models continued to perform satisfactorily, although the error statistics of some models for overcast skiesworsened. PB Elsevier SN 0273-1177 YR 2022 FD 2022-07 LK http://hdl.handle.net/10259/7275 UL http://hdl.handle.net/10259/7275 LA eng NO The authors gratefully acknowledge the financial support provided by the Spanish Ministry of Science & Innovation under the I + D+i state program “Challenges Research Projects” (Ref. RTI2018-098900-B-I00). DS Repositorio Institucional de la Universidad de Burgos RD 29-mar-2024