Analysis of effective resistance calculation methods and their effect on modelling evapotranspiration in two different patches of vegetation in semi-arid SE Spain

International audienceEffective parameters are of major importance in modelling surface fluxes at different scales of spatial heterogeneity. Different ways to obtain these effective parameters for their use in meso-scale and GCM models have been studied. This paper deals with patch-scale heterogeneity, where effective resistances were calculated in two patches with different vegetation (Retama sphaerocarpa (L.) Boiss shrubs, and herbaceous plants) using different methods: aggregating soil and plant resistances in parallel, in series or by an average of both. Effective aerodynamic resistance was also calculated directly from patch fluxes. To assess the validity of the different methods used, the Penman-Monteith equation was used with effective resistances to estimate the total ?E for each patch. The ?E estimates found for each patch were compared to Eddy Covariance system measurements. Results showed that for effective surface resistances, parallel aggregation of soil and plant resistances led to ?E estimates closer to the measured ?E in both patches (differences of around 10%). Results for effective aerodynamic resistances differed depending on the patch considered and the method used to calculate them. The use of effective aerodynamic resistances calculated from fluxes provided less accurate estimates of ?E compared to the measured values, than the use of effective aerodynamic resistances aggregated from soil and plant resistances. The results reported in this paper show that the best way of aggregating soil and plant resistances depends on the type of resistance, and the type of vegetation in the patch

Analysis of effective resistance calculation methods and their effect on modelling evapotranspiration in two different patches of vegetation in semi-arid SE Spain

Effective parameters are of major importance in modelling surface fluxes at different scales of spatial heterogeneity. Different ways to obtain these effective parameters for their use in meso-scale and GCM models have been studied. This paper deals with patch-scale heterogeneity, where effective resistances were calculated in two patches with different vegetation (Retama sphaerocarpa (L.) Boiss shrubs, and herbaceous plants) using different methods: aggregating soil and plant resistances in parallel, in series or by an average of both. Effective aerodynamic resistance was also calculated directly from patch fluxes. To assess the validity of the different methods used, the Penman-Monteith equation was used with effective resistances to estimate the total λE for each patch. The λE estimates found for each patch were compared to Eddy Covariance system measurements. Results showed that for effective surface resistances, parallel aggregation of soil and plant resistances led to λE estimates closer to the measured λE in both patches (differences of around 10%). Results for effective aerodynamic resistances differed depending on the patch considered and the method used to calculate them. The use of effective aerodynamic resistances calculated from fluxes provided less accurate estimates of λE compared to the measured values, than the use of effective aerodynamic resistances aggregated from soil and plant resistances. The results reported in this paper show that the best way of aggregating soil and plant resistances depends on the type of resistance, and the type of vegetation in the patch.This work received financial support from several different research projects: the PROBASE (ref.: CGL2006-11619/HID) and CANOA (ref.: CGL2004-04919-C02-01/HID) projects funded by the Spanish Ministry of Education and Science; and the BACAEMA (“Balance de carbono y de agua en ecosistemas de matorral mediterráneo en Andalucía: Efecto del cambio climático”, RNM-332) and CAMBIO (“Efectos del cambio global sobre la biodiversidad y el funcionamiento ecosistémico mediante la identificación de áreas sensibles y de referencia en el SE ibérico”, RNM 1280) projects funded by the regional government Junta de Andalucía. The first author enjoyed a pre-doctoral grant from the Spanish Ministry of Science and Technology

Cloud Screening and Quality Control Algorithm for Star Photometer Data: Assessment with Lidar Measurements and with All-sky Images

This paper presents the development and set up of a cloud screening and data quality control algorithm for a star photometer based on CCD camera as detector. These algorithms are necessary for passive remote sensing techniques to retrieve the columnar aerosol optical depth, delta Ae(lambda), and precipitable water vapor content, W, at nighttime. This cloud screening procedure consists of calculating moving averages of delta Ae() and W under different time-windows combined with a procedure for detecting outliers. Additionally, to avoid undesirable Ae(lambda) and W fluctuations caused by the atmospheric turbulence, the data are averaged on 30 min. The algorithm is applied to the star photometer deployed in the city of Granada (37.16 N, 3.60 W, 680 ma.s.l.; South-East of Spain) for the measurements acquired between March 2007 and September 2009. The algorithm is evaluated with correlative measurements registered by a lidar system and also with all-sky images obtained at the sunset and sunrise of the previous and following days. Promising results are obtained detecting cloud-affected data. Additionally, the cloud screening algorithm has been evaluated under different aerosol conditions including Saharan dust intrusion, biomass burning and pollution events

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

Impact of mineral dust on short wave and long wave radiation: evaluation of different vertically resolved parameterization sin 1-D radiative transfer computations

Aerosol radiative properties are investigated in southeastern Spain during a dust event on 16–17 June 2013 in the framework of the ChArMEx/ADRIMED (Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region) campaign. Particle optical and microphysical properties from ground-based sun/sky photometer and lidar measurements, as well as in situ measurements on board the SAFIRE ATR 42 French research aircraft, are used to create a set of different levels of input parameterizations, which feed the 1-D radiative transfer model (RTM) GAME (Global Atmospheric ModEl). We consider three datasets: (1) a first parameterization based on the retrievals by an advanced aerosol inversion code (GRASP; Generalized Retrieval of Aerosol and Surface Properties) applied to combined photometer and lidar data, (2) a parameterization based on the photometer columnar optical properties and vertically resolved lidar retrievals with the two-component Klett–Fernald algorithm, and (3) a parameterization based on vertically resolved optical and microphysical aerosol properties measured in situ by the aircraft instrumentation. Once retrieved, the outputs of the RTM in terms of both shortwave and longwave radiative fluxes are compared against ground and in situ airborne measurements. In addition, the outputs of the model in terms of the aerosol direct radiative effect are discussed with respect to the different input parameterizations. Results show that calculated atmospheric radiative fluxes differ no more than 7 % from the measured ones. The three parameterization datasets produce a cooling effect due to mineral dust both at the surface and the top of the atmosphere. Aerosol radiative effects with differences of up to 10 W m−2 in the shortwave spectral range (mostly due to differences in the aerosol optical depth) and 2 W m−2 for the longwave spectral range (mainly due to differences in the aerosol optical depth but also to the coarse mode radius used to calculate the radiative properties) are obtained when comparing the three parameterizations. The study reveals the complexity of parameterizing 1-D RTMs as sizing and characterizing the optical properties of mineral dust is challenging. The use of advanced remote sensing data and processing, in combination with closure studies on the optical and microphysical properties from in situ aircraft measurements when available, is recommended.This work is part of the ChArMEx project supported by CNRS-INSU, ADEME, Météo-France, and CEA in the framework of the multidisciplinary program MISTRALS (Mediterranean Integrated STudies at Regional And Local Scales; http://mistrals-home.org/, last access: 15 January 2018). Lidar measurements were supported by the ACTRIS (Aerosols, Clouds, and Trace Gases Research Infrastructure Network) Research Infrastructure Project funded by the European Union's Horizon 2020 research and innovation program under grant agreement no. 654109. The Barcelona team acknowledges the Spanish Ministry of Economy and Competitiveness (project TEC2015-63832-P) and EFRD (European Fund for Regional Development); the Department of Economy and Knowledge of the Catalan autonomous government (grant 2014 SGR 583) and the Unidad de Excelencia Maria de Maeztu (project MDM-2016-0600) financed by the Spanish Agencia Estatal de Investigación. The authors also thank the Spanish Ministry of Science, Innovation and Universities (ref. CGL2017-90884-REDT). This work was also supported by the Juan de la Cierva-Formación program (grant FJCI-2015-23904). Paola Formenti and Cyrielle Denjean acknowledge the support of the French National Research Agency (ANR) through the ADRIMED program (contract ANR-11-BS56-0006)

Quantifying traffic, biomass burning and secondary source contributions to atmospheric particle number concentrations at urban and suburban sites

In this study, we propose a new approach to determine the contributions of primary vehicle exhaust (N-1(ff)), primary biomass burning (N-1(bb)) and secondary (N-2) particles to mode segregated particle number concentrations. We used simultaneous measurements of aerosol size distribution in the 12-600 nm size range and black carbon (BC) concentration obtained during winter period at urban and suburban sites influenced by biomass burning (BB) emissions. As expected, larger aerosol number concentrations in the 12-25 and 25-100 nm size ranges are observed at the urban site compared to the suburban site. However, similar concentrations of BC are observed at both sites due to the larger contribution of BB particles to the observed BC at suburban (34%) in comparison to urban site (23%). Due to this influence of BB emissions in our study area, the application of the Rodriguez and Cuevas (2007) method, which was developed for areas mainly influenced by traffic emissions, leads to an overestimation of the primary vehicle exhaust particles concentrations by 18% and 26% in urban and suburban sites, respectively, as compared to our new proposed approach. The results show that (1) N-2 is the main contributor in all size ranges at both sites, (2) N-1(ff) is the main contributor to primary particles (>70%) in all size ranges at both sites and (3) N-1(bb) contributes significantly to the primary particles in the 25-100 and 100-600 nm size ranges at the suburban (24% and 28%, respectively) and urban (13% and 20%, respectively) sites. At urban site, the N-1(ff) contribution shows a slight increase with the increase of total particle concentration, reaching a contribution of up to 65% at high ambient aerosol concentrations. New particle loination events are an important aerosol source during summer noon hours but, on average, these events do not implicate a considerable contribution to urban particles. (C) 2021 Elsevier B.V. All rights reserved.Peer reviewe

Aerosol number fluxes and concentrations over a southern European urban area

Although cities are an important source of aerosol particles, aerosol number flux measurements over urban areas are scarce. These measurements are however important as they can allow us to identify the different sources/sinks of aerosol particles and quantify their emission contributions. Therefore, they can help us to understand the aerosol impacts on human health and climate, and to design effective mitigation strategies through the reduction of urban aerosol emissions. In this work we analyze the aerosol number concentrations and fluxes for particles with diameters larger than 2.5 nm measured by eddy covariance technique at an urban area (Granada city, Spain) from November 2016 to April 2018. This is the first study of particle number flux in an urban area in the Iberian Peninsula and is one of the few current studies that report long-term aerosol number flux measurements. The results suggest that, on average, Granada urban area acted as a net source for atmospheric aerosol particles with median particle number flux of 150 x 10(6) m(-2) s(-1). Downward negative fluxes were observed in only 12% of the analyzed data, and most of them were observed during high aerosol load conditions. Both aerosol number fluxes and concentrations were maximum in winter and 50% larger than those measured in summer due to the increased emissions from domestic heating, burning of residual agricultural waste in the agricultural area surrounding the site, as well as to the lower aerosol dilution effects during winter. The analysis of the seasonal diurnal variability of the aerosol number concentration revealed the significant impact of traffic emissions on aerosol population over Granada urban area in all seasons. It also shows the impact of domestic heating and agricultural waste burning emissions in winter as well as the influence of new particle formation processes in summer and spring seasons. Closer analysis by wind sector demonstrated that both aerosol concentrations and fluxes from urban sector (where high density of anthropogenic sources is located) were lower than those from rural sector (which includes agricultural area but also the main highway of the city). This evidences the strong impact of aerosol emissions from traffic circulating on the highway on aerosol population over our measurement site.Peer reviewe

Experimental techniques for the calibration of lidar depolarization channels in EARLINET

Particle depolarization ratio retrieved from lidar measurements are commonly used for aerosol-typing studies, microphysical inversion, or mass concentration retrievals. The particle depolarization ratio is one of the primary parameters that can differentiate several major aerosol components but only if the measurements are accurate enough. The accuracy related to the retrieval of particle depolarization ratios is the driving factor for assessing and improving the uncertainties of the depolarization products. This paper presents different depolarization calibration procedures used to improve the quality of the depolarization data. The results illustrate a significant improvement of the depolarization lidar products for all the selected lidar stations that have implemented depolarization calibration procedures. The calibrated volume and particle depolarization profiles at 532 nm show values that fall within a range that is generally accepted in the literature