Radiative forcing under mixed aerosol conditions

The mixture of mineral dust with biomass burning or urban-industrial aerosols presents significant differences in optical properties when compared to those of the individual constituents, leading to different impacts on solar radiation levels. This effect is assessed by estimating the direct radiative forcing (ΔF) of these aerosols from solar flux models using the radiative parameters derived from the Aerosol Robotic Network (AERONET). These data reveal that, in oceanic and vegetative covers (surface albedo (SA) 0.30 are not present in East Asia region. At the bottom of atmosphere (BOA) the maximum ΔF values are associated with the highest AOD levels obtained for the mixture of mineral dust and biomass burning aerosols (−130 ± 44 Wm−2 with AOD = 0.8 ± 0.4 for SA < 0.30).Support for this study was given by Spanish Ministry of Education and Science, projects CGL2005‐03428‐C04‐02, CGL2007‐66477‐C02‐02/CLI, PI042005/033, and CGL2008‐04740/CLI

Radiative properties of aerosols in Saharan dust outbreaks using ground-based and satellite data: applications to radiative forcing

We report on measurements of atmospheric transmission (ATT) and aerosol optical depth (AODT) made at three wavelengths (368, 500, and 778 nm) with a spectroradiometer placed on Tenerife (28.5°N, 16.3°W), Canary Islands. Using the National Oceanic and Atmospheric Administration (NOAA) advanced very high resolution radiometer (AVHRR) channel 1, we also measured the aerosol optical depth (AODS) and albedo over a region of the North Atlantic Ocean extending from 15°–35°N to 12°–25°W. We observe large changes in ATT and AODT when dust outbreaks pass over this region. Using all these data, we derive the asymmetry factor (g), the single-scattering albedo (ω), and the local mean AODT and we compute the direct radiative forcing ΔF attributable to mineral dust. The local radiative forcing obtained is over the ocean ΔF = −9.7 W/m2 and for the land ΔF = −4.5 W/m2 with an error of ±25%. Extending these results to global-scale averages, we obtain values of ΔF of −1.22 W/m2 over the ocean and −0.57 W/m2 over land. The forcings attributable to dust are comparable in magnitude to those reported in the literature for anthropogenic sulphate and for biomass burning aerosols.We wish to thank the Gobierno Autónomo de Canarias for its financial support by contract 4/95, the Comisi6n Interministerial de Ciencia y Tecnologia (CICYT) by contract CLI97- 0453, and the University of La Laguna by contract 1802260003. A portion of this work was carried out as part of the Atmosphere/Ocean Chemistry Experiment (AEROCE) and supported by the National Science Foundation grants ATM-9414808, ATM-9414812, and ATM- 9414846

Aerosol radiative forcing and forcing efficiency in the UVB for regions affected by Saharan and Asian mineral dust

The influence of mineral dust on ultraviolet energy transfer is studied for two different mineralogical origins. The aerosol radiative forcing ΔF and the forcing efficiency at the surface ΔFeff in the range 290–325 nm were estimated in ground-based stations affected by the Saharan and Asian deserts during the dusty seasons. UVB solar measurements were taken from the World Ozone and Ultraviolet Data Center (WOUDC) for four Asian stations (2000–04) and from the Santa Cruz Observatory, Canary Islands (2002–03), under Gobi and Sahara Desert influences, respectively. The Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth at 550 nm was used to characterize the aerosol load τ, whereas the aerosol index provided by the Total Ozone Mapping Spectrometer (TOMS) sensor was employed to identify the mineral dust events. The ΔF is strongly affected by the aerosol load, the values found being comparable in both regions during the dusty seasons. Under those conditions, ΔF values as large as −1.29 ± 0.53 W m−2 (τ550 = 0.48 ± 0.24) and −1.43 ± 0.38 W m−2 (τ550 = 0.54 ± 0.26) were reached under Saharan and Asian dust conditions, respectively. Nevertheless, significant differences have been observed in the aerosol radiative forcing per unit of aerosol optical depth in the slant path, τS. The maximum ΔFeff values associated with dust influences were −1.55 ± 0.20 W m−2 τS550−1 for the Saharan region and −0.95 ± 0.11 W m−2 τS550−1 in the Asian area. These results may be used as a benchmark database for establishing aerosol corrections in UV satellite products or in global climate model estimations.We acknowledge the MCYT (Ministry of Science and Technology, Spain) and F.E.D.E.R. foundations (E.U.) for their economic support of projects CGL2004-05984-C07-05, CGL2005-03428-C04-02, CGL2007-66477-C02-02/CLI, CGL2008-04740/CLI and PI042005/033

Spanish Dentists’ Awareness, Knowledge, and Practice Regarding COVID-19: A Multiple Regression Analysis

The authors thank the Spanish Society of Epidemiology and Oral Public Health (SESPO) for expert supervision of the questionnaire; the Spanish General Council of Dentists (GCD) and the Spanish societies of dental hygienists for their rapid dissemination of the survey to their members.Introduction: During the first months of the coronavirus disease 2019 (COVID-19) pandemic, Spain had the highest mortality rate and the second-highest infection rate in the world. Objective: To analyze the occupational situation of dentists, hygienists, and dental auxiliary staff during the peak of the pandemic, after the state of alarm was declared in Spain, and when the state of alarm was declared. In addition, a possible relationship between the geographical distribution of infected people and the availability of individual protection systems was investigated. Material and Methods: A cross-sectional questionnaire was answered by 6470 dentists and dental staff via WhatsApp and social media. Results: A total of 1 in 4 dental professionals ceased working completely. Of those that kept working, 25.28% of dentists and 19.61% of hygienist-auxiliary were equipped with filtering face piece (FFP) 2 masks (P < .05), and 61.8% complied with the official protection recommendations set by the General Council of Dentists of Spain. Nearly 59.4% of respondents had symptoms, but only 1.5% of dentists were tested, with 14% of dentists in isolation at the time of response. Overall, it is suggested that 10% of dental professionals may have been in direct contact with the coronavirus. Conclusions: Direct contact of Spanish dental health professionals with severe acute respiratory syndrome coronavirus disease 2 (SARS CoV-2) has been high during the most active phase of the pandemic. Dental professionals did not have personal protective equipment (PPE) necessary to care for patients, a situation that justified the reduction in scheduled dental care and only emergencies being treated. The Spanish geographical regions with the highest number of contagions had the least amount of individual protective resources (FFP2 and FFP3masks)

Lidar ratio derived for pure dust aerosols: multi-year micro pulse lidar observations in a Saharan dust-influenced region

El volumen 119 de 2016 de la revista EPJ Web of Conferences recoge las ponencias del 27th International Laser Radar Conference (ILRC 27)A seasonal distribution of the Lidar Ratio (LR, extinction-to-backscattering coefficient ratio) for pure Saharan dust particles has been achieved. Simultaneous MPLNET/Micro Pulse lidar measurements in synergy with AERONET sun-photometer data were collected in the Tenerife area, a Saharan dust-influenced region, from June 2007 to November 2009. Dusty cases were mostly observed in summertime (71.4 % of total dusty cases). No differences were found among the LR values derived for spring, summertime and autumn times (a rather consistent seasonally averaged LR value of 57 sr is found). In wintertime, however, a higher mean LR is derived (65 sr), associated likely with a potential contamination from fine biomass burning particles coming from Sahel area during wintertime deforestation fires period. Results, obtained from a free-tropospheric pristine station (AEMET/Izaña Observatory) under Saharan dust intrusion occurrence, provide a more realistic perspective about LR values to be used in elastic lidar-derived AOD inversion for Saharan pure dust particles, and hence in improving CALIPSO AOD retrievals.This work has been supported by the Spanish Ministerio de Economía y Competitividad (MINECO) under grant CGL2011-24891 (AMISOC project)

Influencia de los aerosoles absorbentes en el UV en la medida de la columna total de ozono desde satélite

Ponencia presentada en: 1er Encuentro sobre Meteorología y Atmósfera de Canarias, celebrado en el Puerto de la Cruz, los días 12,13 y 14 de noviembre de 2003. El encuentro estuvo organizado por el Centro Meteorológico Territorial en Canarias Occidental, con la colaboración del Observatorio Atmosférico de Izaña y del Grupo de Física de la Atmósfera de la Facultad de Física (Universidad de La Laguna)El control de la capa de ozono es una de las tareas más importantes en la evaluación de los posibles riesgos producidos por la radiación UV. De igual forma, los aerosoles atmosféricos también modifican el balance de energía en el sistema, de forma directa mediante procesos de scattering y absorción de radiación, y de forma indirecta, mediante la modificación de ciclo de vida de las nubes. En este trabajo se han estudiado las posibles diferencias entre el ozono medido por el TOMS y el medido desde Tierra en presencia de aerosoles; estos vienen determinados por el índice de aerosoles, Al del TOMS. Para realizar este estudio se ha tomado una base de datos superior a 7GB, desde el 1 de Noviembre de 1978 hasta el 31 de Diciembre de 2001, correspondientes a /os datos del TOMS, y las 214 estaciones que hay repartidas por todo el planeta. El resultado obtenido para estas diferencias muestra que no existe diferencia apreciable entre los valores de 0 3 TOMS y los obtenidos desde tierra con el Al-TOMS.Este trabajo ha sido financiado por los proyectos REN2001-0609-C02/CLI y REN2000-0903-C08- 06/CLI del Ministerio de Ciencia y Tecnología

Simulation of mineral dust effects on UV radiation levels

The role played by aerosols on UV radiative transfer in the atmosphere is very uncertain. This is especially true regarding mineral dust. To determine the sensitivity of the UV levels to the presence of this atmospheric specie, we have simulated the UV irradiance with different vertical distributions of mineral dust. We have used a discrete ordinates radiative transfer model to obtain the UV levels both at sea level and at 3000 m. We have computed the aerosol single-scattering albedo, the phase function, and the asymmetry factor by Mie scattering theory. The background aerosol profiles were taken from WCRP [1986] models, whereas the radiative properties of mineral dust have been calculated from the aerosol size distribution obtained during Saharan dust invasions at Tenerife island (28.5°N, 16.3°W). The values for aerosol optical depth assumed as input for the model calculations are 0.2 (at 550 nm) for clean background aerosols and 0.3 (at 550 nm) for the mineral dust component. From the results we can conclude that the dust vertical size distribution can affect the irradiance ratio F (with Saharan dust)/F (no Saharan dust) by 2–4%. In addition, we observe that to the same total optical depth the diffuse UV levels depend not only on the vertical dust distribution but also on the background aerosol vertical distribution. We have computed differences for the diffuse radiation fluxes of about 5% between a maritime and a continental model to the same mineral dust vertical distribution.This work has been supported by the CICYT (Comisión Interministerial de Ciencia y Tecnologia- Spanish Government) under contract CLI97-0453 and the Gobierno Autónomo de Canarias by contract 4/95

Aerosol lidar intercomparison in the framework of SPALINET- the SPAnish LIdar NETwork: methodology and results

A group of eight Spanish lidars was formed in order to extend the European Aerosol Research Lidar Network-Advanced Sustainable Observation System (EARLINET-ASOS) project. This study presents intercomparisons at the hardware and software levels. Results of the system intercomparisons are based on range-square-corrected signals in cases where the lidars viewed the same atmospheres. Comparisons were also made for aerosol backscatter coefficients at 1064 nm (2 systems) and 532 nm (all systems), and for extinction coefficients at 532 nm (2 systems). In total, three field campaigns were carried out between 2006 and 2007. Comparisons were limited to the highest layer found before the free troposphere, i.e., either the atmospheric boundary layer or the aerosol layer just above it. Some groups did not pass the quality assurance criterion on the first attempt. Following modification and improvement to these systems, all systems met the quality criterion. The backscatter algorithm intercomparison consisted of processing lidar signal profiles simulated for two types of atmospheric conditions. Three stages with increasing knowledge of the input parameters were considered. The results showed that all algorithms work well when all inputs are known. They also showed the necessity to perform, when possible, additional measurements to attain better estimation of the lidar ratio, which is the most critical unknown in the elastic lidar inversion

El balneum oriental del castellum tingitano de Tamuda. Estudio arqueo-arquitectónico y propuesta de valorización

In this paper we approach the architecture of the balneum discovered in the eastern quarter next to the Roman fort of Tamuda (Tetouan, Morocco), which are probably the main baths of the settlement. To carry out this study, we have unified the results derived from the archaeo-architectural analysis with photogrammetry and volumetric surveys, so it has been possible to propose a spatial articulation. This one responds to all the identified architectural elements and the contexts recovered through their excavation. The result is an interpretative proposal that explains the spaces and their internal routes and that offers a volumetric survey, both of them according to the parallels identified and to the discovered structures. This output allows us to properly approach the reality of the main balneum of the Roman fort. We have besides incorporated a current valorization proposal that entails the protection of the building and its integration within a circuit of visits designed ad hoc.En este trabajo nos acercamos a la arquitectura del balneum descubierto en el barrio oriental del campamento romano de Tamuda (Tetuán, Marruecos), el cual posiblemente es el principal edificio de baños del asentamiento. Para realizar este estudio, hemos unificado los resultados derivados del análisis arqueo-arquitectónico con fotogrametría y levantamientos volumétricos, de manera que se ofrece una propuesta de articulación espacial. Esta responde a todos los elementos arquitectónicos identificados y a los contextos recuperados a través de su excavación. El resultado es una propuesta interpretativa que da sentido a los espacios y recorridos interiores y de levantamiento volumétrico, ambos coherentes con los paralelos identificados y con las estructuras descubiertas, que permiten acercarnos de manera más clara a la realidad del principal balneum del campamento. Como complemento, se ha incorporado una propuesta de valorización actual que conlleva la protección del edificio y su inserción en un circuito de visitas ad hoc