Adaptation of an empirical model for erythemal ultraviolet irradiance

In this work we adapt an empirical model to estimate ultraviolet erythemal irradiance (UVER) using experimental measurements carried out at seven stations in Spain during four years (2000–2003). The measurements were taken in the framework of the Spanish UVB radiometric network operated and maintained by the Spanish Meteorological Institute. The UVER observations are recorded as half hour average values. The model is valid for all-sky conditions, estimating UVER from the ozone columnar content and parameters usually registered in radiometric networks, such as global broadband hemispherical transmittance and optical air mass. One data set was used to develop the model and another independent set was used to validate it. The model provides satisfactory results, with low mean bias error (MBE) for all stations. In fact, MBEs are less than 4% and root mean square errors (RMSE) are below 18% (except for one location). The model has also been evaluated to estimate the UV index. The percentage of cases with differences of 0 UVI units is in the range of 61.1% to 72.0%, while the percentage of cases with differences of ±1 UVI unit covers the range of 95.6% to 99.2%. This result confirms the applicability of the model to estimate UVER irradiance and the UV index at those locations in the Iberian Peninsula where there are no UV radiation measurements.This work was supported by CICYT from the Spanish Ministry of Science and Technology through projects CIRRUS REN2003-03175 and PANDORA-CALIPSO CGL2004- 05984-C07-03, REN 2003- 03175 and Andalusian Regional Government project P06-RNM-01503. The “Instituto Nacional de Meteorología” kindly provided the radiometric and meteorological information for the stations used in this study

A new empirical model to estimate hourly diffuse photosynthetic photon flux density

This is a preprint version of a paper accepted to be published in "Foyo-Moreno, I.; Alados-Arboledas, I.; Alados-Arboledas, L. A new empirical model to estimate hourly diffuse photosynthetic photon flux density. Atmospheric Research, 203: 189-196 (2018)", doi: https://doi.org/10.1016/j.atmosres.2017.12.012Knowledge of the photosynthetic photon flux density (Qp) is critical in different applications dealing with climate change, plant physiology, biomass production, and natural illumination in greenhouses. This is particularly true regarding its diffuse component (Qpd), which can enhance canopy light-use efficiency and thereby boost carbon uptake. Therefore, diffuse photosynthetic photon flux density is a key driving factor of ecosystem-productivity models. In this work, we propose a model to estimate this component, using a previous model to calculate Qp and furthermore divide it into its components. We have used measurements in urban Granada (southern Spain), of global solar radiation (Rs) to study relationships between the ratio Qpd/Rs with different parameters accounting for solar position, water-vapour absorption and sky conditions. The model performance has been validated with experimental measurements from sites having varied climatic conditions. The model provides acceptable results, with the mean bias error and root mean square error varying between − 0.3 and − 8.8% and between 9.6 and 20.4%, respectively.This work was supported by the Andalusia Regional Government project P12-RNM-2409, by the Spanish Ministry of Economy and Competitiveness projects CGL2013-45410-R and CGL2016-81092-R, and by the European Union's Horizon 2020 research and innovation programme project ACTRIS-2 (grant agreement No 654109)

Improving the Estimation of the Diffuse Component of Photosynthetically Active Radiation (PAR)

Most weather forecasting models are not able to accurately reproduce the great variability existing in the measurements of the diffuse component of photosynthetically active radiation (PAR; 400–700 nm) under all sky conditions. Based on the well-known relationship between the diffuse fraction (k) and the clearness index (kt), this study addresses improvements in estimations by proposing adaptations of previous models, which were previously applied only to the total solar irradiance (TSI; 280–3,000 nm). In order to reproduce this variability, additional parameters were introduced. The models were tested employing a multisite database gathered at the Mediterranean basin. Since Artificial Neural Network (ANN) models are not limited to fixed coefficients to predict the diffuse fraction of PAR (kPAR), these types of models are more accurate than empirical ones, reaching determination coefficients (r2) up to 0.998. However, the simpler linear model proposed by Foyo-Moreno et al. (2018), https://doi.org/10.1016/j.atmosres.2017.12.012 shows a similar performance to the ANN models, directly predicting the diffuse component of PAR (PARDiffuse) from TSIDiffuse, with a r2 up to 0.997. Results obtained here also determine that the most important variables for estimating PARDiffuse are kt or kt,PAR, and the apparent solar time (AST). Therefore, PARDiffuse can be modeled using TSI measured in most radiometric stations, reaching r2 up to 0.858 for empirical models and 0.970 for ANN models. This modified approach will allow for the very accurate construction of long-term data series of PARDiffuse in regions where continuous measurements of PAR are not available.Spanish Ministry of Economy and Competitiveness (projects CGL2017-90884- REDT and PID2020-120015RB-I00)Andalusia Regional Government, University of Granada and FEDER funds (project B-RNM-524-UGR20)Open Access funding provided by University of Helsink

Aerosol radiative effects in photosynthetically active radiation and total irradiance at a Mediterranean site from an 11-year database

This study addresses the analysis of the aerosol radiative forcing (ARF) and aerosol forcing efficiency (AFE) at surface in the Photosynthetically Active and Total radiation ranges in a Southwest Mediterranean site. A thorough analysis of a long-term database (2008–2018) has been performed, bringing very valuable results about both, the absolute values and trends in ARF and AFE for both spectral intervals. The largest monthly mean for aerosol optical depth at 500 nm (AOD500) is found in summer (0.16 at July and August) meanwhile the lowest value is in winter (0.08 at November and December), with an interannual range varying from 0.11 ± 0.03 (in 2018) to 0.17 ± 0.03 (in 2014). The AFE variation range has been estimated between −12 and − 198 Wm−2τ−1 for PAR and between −9 and − 450 Wm−2τ−1 for Total irradiance. ARF varies between −1 Wm−2 and -23 Wm−2 in the PAR range, taking values from −1 to −40 Wm−2 in the Total one. This result points out the relevance of the aerosol effects on the PAR range, which can involve up to a 50% of the Total ARF. Moreover, a notable dependence of ARF and AFE on the solar position has been detected, increasing their absolute values at solar zenith angle from 0o to 45o-60o and decreasing to zero for lower solar positions. Additionally, this analysis has revealed the existence of a significant downward trend in AFE values for PAR, with a slope of 2.7 Wm−2τ−1year−1. Although the slope is positive, taking into account that the AFE values are negative, the slope value implies that the aerosol cooling radiative effect of aerosols is decreasing. However, no trends have been detected neither in AFE nor ARF values in the Total solar range. These results evidence the long-term aerosol effects over the different spectral intervals and emphasize the need for detailed analysis of the aerosol radiative effects on fundamental spectral intervals such as the PAR range.Peer reviewe

Contribution to column-integrated aerosol typing based on Sunphotometry using different criteria

This study analyses the aerosol optical and microphysical properties obtained by the Aerosol Robotic Network (AERONET) in seven different sites operating in the Iberian Peninsula during three coincident years (2010−2012) with the objective of studying different aerosol typing approaches. This area is of interest due to its location between the Sahara desert (the largest source of natural aerosols in the world) and mainland Europe (a relevant source of anthropogenic aerosols). In particular, we study the aerosol optical depth (AOD), Angström parameter (α440–870) and fine mode fraction (FMF), which are estimated from direct sun irradiance measurements. Additionally, the single scattering albedo (ωo) and aerosol particle size distribution (PSD), which are computed using additional sky radiances measurements under cloudless skies, are used in our analyses. The analyses show aerosol seasonal patterns in the AOD with maximum values in summer/spring and minimum values in winter/autumn for all the analysed stations. For α440–870, there are differences from site to site, with maximum values in winter and minimum values in summer for the southern locations, while there is not a remarkable pattern for the eastern locations close to the Mediterranean coast. The frequent and intense Saharan dust outbreaks over the southern Iberian Peninsula and the intense anthropogenic activity in the eastern urban locations are behind these seasonal patterns in the AOD and α440–870. In this work, two of the most employed classification schemes of aerosol type in the literature are used: one is based on the AOD and α440–870, the other one is based on ωo at 440 nm and the FMF and a new classification scheme based on ωo at 440 nm and FMF is proposed. The results revealed that the new classification method is more appropriate for distinguishing the aerosol types that affect the Iberian Peninsula. The relationship derived here between Δωo = ωo (440)- ωo (1020) and the FMF is demonstrated to be useful for aerosol type classification when no measurements of the sky radiances, and consequently of ωo(440), are available. Alternatively, the relationship between the ratio Δωo/ωo(440) and the FMF can be used because (Δωo/ωo) provides information about both the spectral ωo and the absolute values.Spanish Ministry of Economy and Competitiveness through projects CGL2013-45410-RSpanish Ministry of Economy and Competitiveness through projects CGL2016-81092-RSpanish Ministry of Economy and Competitiveness through projects CGL2017-90884-REDTAndalusia Regional Government through projects P12-RNM-240

Interactive Graphical Simulations For Experimental Physics Learning

Se pesenta un material interactivo multimedia desarrollado para contribuir al aprendizaje del campo electrostático de cargas puntuales.Las simulaciones del campo electrostático de conjuntos de cargas eléctricas disponibles en Internet no tienen en cuenta, generalmente, el valor de las cargas. Suelen dibujar un número constante de líneas, lo que a veces genera figuras enmarañadas de difícil interpretación. Algunas simulaciones sí dibujan un número de líneas proporcional al valor de las cargas, pero sólo muestran unos pocos ejemplos y no permiten el desplazamiento de las cargas, es decir, son poco interactivos. El applet presentado aquí se diseñó intentando resolver todas estas limitaciones. La simulación permite al usuario introducir un número arbitrario de cargas eléctricas con los valores (en nC) que considere más oportuno, y visualizar tanto las líneas de campo eléctrico creadas por ese conjunto de cargas como, opcionalmente, las curvas isopotenciales. La simulación permite manipular la posición de las cargas y observar, en tiempo real, cómo se modifican las líneas de campo y de potencial. El número de líneas de campo que salen (positivas) o entran (negativas) de cada carga es proporcional al valor de la misma, lo que permite trabajar el concepto de proporcionalidad entre el flujo del campo electrostático y el número de líneas de campo que atraviesan una superficie cerrada (ley de Gauss). Finalmente, el simulador permite introducir una carga libre y observar la evolución de su trayectoria bajo la influencia del sistema de cargas que hayamos diseñado.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Study of the relative humidity dependence of aerosol light-scattering in southern Spain

This investigation focuses on the characterisation of the aerosol particle hygroscopicity. Aerosol particle optical properties were measured at Granada, Spain, during winter and spring seasons in 2013. Measured optical properties included particle light-absorption coefficient (σap) and particle light-scattering coefficient (σsp) at dry conditions and at relative humidity (RH) of 85±10%. The scattering enhancement factor, f(RH=85%), had a mean value of 1.5±0.2 and 1.6±0.3 for winter and spring campaigns, respectively. Cases of high scattering enhancement were more frequent during the spring campaign with 27% of the f(RH=85%) values above 1.8, while during the winter campaign only 8% of the data were above 1.8. A Saharan dust event (SDE), which occurred during the spring campaign, was characterised by a predominance of large particles with low hygroscopicity. For the day when the SDE was more intense, a mean daily value of f(RH=85%)=1.3±0.2 was calculated. f(RH=85%) diurnal cycle showed two minima during the morning and afternoon traffic rush hours due to the increase in non-hygroscopic particles such as black carbon and road dust. This was confirmed by small values of the single-scattering albedo and the scattering Ångstrom exponent. A significant correlation between f(RH=85%) and the fraction of particulate organic matter and sulphate was obtained. Finally, the impact of ambient RH in the aerosol radiative forcing was found to be very small due to the low ambient RH. For high RH values, the hygroscopic effect should be taken into account since the aerosol forcing efficiency changed from −13 W/m2 at dry conditions to −17 W/m2 at RH=85%

Live lecture screencast recording: a proposal to simplify the tasks associated with content production for video-teaching

Se trata de un resumen (Abstract) de la contribución. El acuerdo de transferencia de copyright del trabajo completo es incompatible con el depósito del mismo en RIUMA.Se describe la implementación inicial de un método simplificado de grabación en directo de sesiones de clase en asignaturas de las Escuelas de Ingeniería de la Universidad de Málaga. La simplificación se logra al incorporar en la actividad diaria del aula ciertas características típicas de la grabación en diferido de mini videos docentes. En una configuración mínima se graba únicamente el audio y el video en pantalla de la clase, evitando los desafíos técnicos y las dificultades que implica la grabación de otros elementos como la pizarra. Esto implica el uso de anotaciones en pantalla en tiempo real para reemplazar completamente las anotaciones en la pizarra.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. I Plan Propio Integral de Docencia. Universidad de Málaga. Universidad de Málaga. Vicerectorado de Personal Docente e Investigador, Proyectos de Innovación Educativa (PIE 17-018

Assessing pollen extreme events over a Mediterranean site: Role of local surface meteorology

The presence of very high pollen levels in the atmosphere is associated with a strong impact on health and a worsening of symptoms in people who already have a respiratory disease. However, there is no specification on the aerobiological, environmental and meteorological factors that allow for characterizing a pollen event as of great magnitude due to the significant impact it can cause on the population and the environment. This work proposes criteria to typify the levels of atmospheric pollen as an extreme pollen event (EPE), and aims to determine the meteorological variables that can affect the presence and permanence of high pollen concentrations over a period of time. To address this goal, the quasi-climatological pollen dataset recorded in Granada (Southeastern Spain) during the period 1992-2019, has been used. On the daily accumulated pollen concentrations, the 95th, 97th and 99th percentiles were calculated. Spearman's correlation between the pollen concentration exceeding the proposed thresholds (C>P95, C>P97, C>P99) and surface meteorological variables recorded during up to five days before the event were established in order to identify the meteorological conditions that might affect the EPEs. As for the number of days with values higher than the established percentiles, it has been seen that in the case of total pollen and Olea, Cupressaceae and Pinus, there is a robust monotonically ascending trend throughout the study period. Regarding meteorological variables, relative humidity and 24-h accumulated precipitation are shown as the two most influential variables up to three days before the event, although temperatures, visibility and wind direction also show a correlation with some pollen types. The criteria proposed in this work allow us for classifying high levels of pollen as an EPE, and lay the foundations of these extreme events in a context of climate change in which they will become more frequent.the Spanish Ministry of Economy and Competitiveness (MINECO) for support through project BIOCLOUD (RTI2018-101154-A-100) and INTEGRATYON3 (PID2020.117825GB.C21)Regional Government of Andalusia through project AEROPRE (P18-RT-3820) and ADAPNE (P20-00136)INPARK (B-RNM-474-UGR18)DEM3TRIOS (A-RNM-430-UGR20)Earth System Excellence Units Progra

The role of the lab tutor: a positive experience in the Physics Laboratory for incoming students in 1st year courses

This work is part of a study which main aim is to gain knowledge about students’ learning in a physics laboratory where we strive to use effective, interactive learning techniques to engage students in Physics. The present work was carried out during three consecutive academic years with students in their first year of Industrial Engineering degree (University of Málaga) and is based on the lab tutor role for helping students during the laboratory sessions scheduled for the Physics II subject. First year students tend to be particularly difficult to teach and the lack of experience in practical work and problem solving and a lack of mathematical skills are the greatest cause of difficulty for incoming students. This study highlights the importance of training tutors for the laboratory sessions to effectively deal with this unique cohort. Taking into account the survey results we have collected on the students’ perception of the value of laboratory work and the role of the lab tutor, we can conclude that the proposed activity was well received by the students and it has proved to be a valuable experience for both tutor and tutee. Furthermore, the lab tutoring approach can be implemented with a minimal financial cost or staff time, except for the initial training of the tutors.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec