Volcanic eruption of Cumbre Vieja, La Palma, Spain: A first insight to the particulate matter injected in the troposphere

The volcanic eruption of Cumbre Vieja (La Palma Island, Spain), started on 19 September 2021 and was declared terminated on 25 December 2021. A complete set of aerosol measurements were deployed around the volcano within the first month of the eruptive activity. This paper describes the results of the observations made at Tazacorte on the west bank of the island where a polarized micro-pulse lidar was deployed. The analyzed two-and-a-half months (16 October–31 December) reveal that the peak height of the lowermost and strongest volcanic plume did not exceed 3 km (the mean of the hourly values is 1.43 ± 0.45 km over the whole period) and was highly variable. The peak height of the lowermost volcanic plume steadily increased until week 11 after the eruption started (and 3 weeks before its end) and started decreasing afterward. The ash mass concentration was assessed with a method based on the polarization capability of the instrument. Two days with a high ash load were selected: The ash backscatter coefficient, aerosol optical depth, and the volume and particle depolarization ratios were, respectively, 3.6 (2.4) Mm−1sr−1, 0.52 (0.19), 0.13 (0.07) and 0.23 (0.13) on 18 October (15 November). Considering the limitation of current remote sensing techniques to detect large-to-giant particles, the ash mass concentration on the day with the highest ash load (18 October) was estimated to have peaked in the range of 800–3200 μg m−3 in the lowermost layer below 2.5 km.This research was funded by the Spanish Ministry of Science and Innovation (PID2020- 118793GA-I00, PID2019-104205GB-C21, EQC2018-004686-P and PID2019-103886RB-I00), the H2020 program from the European Union (GA no. 19ENV04, 654109, 778349, 871115 and 101008004), and the Unit of Excellence “María de Maeztu” (MDM-2017-0737) financed by the Spanish State Research Agency (AEI). The authors wish to thank ACTRIS, AEROSPAIN and Junta de Castilla y León (ref: VA227P20) for supporting the calibration of the AERONET sun photometers used in this publication, and also to Ayuntamiento de Tazacorte, Ayuntamiento de Fuencaliente and Cabildo Insular de La Palma for their help in terms of infrastructure and logistics. M.-Á.L.-C. and C.V.C.-P. are supported by the INTA predoctoral contract program. E.J.W. is funded by the NASA Radiation Sciences Program and Earth Observing System.Peer ReviewedArticle signat per 16 autors/es: Michaël Sicard (1,2), Carmen Córdoba-Jabonero (3), Africa Barreto (4), Ellsworth J. Welton (5), Cristina Gil-Díaz (1),Clara V. Carvajal-Pérez (3), Adolfo Comerón (1), Omaira García (4), Rosa García (6), María-Ángeles López-Cayuela (3),Constantino Muñoz-Porcar (1), Natalia Prats (4), Ramón Ramos (4), Alejandro Rodríguez-Gómez (1), Carlos Toledano (7), Carlos Torres (4) // (1) CommSensLab, Department of Signal Theory and Communications, Universitat Politècnica de Catalunya, 08034 Barcelona, Spain; (2) Ciències i Tecnologies de l’Espai-Centre de Recerca de l’Aeronàutica i de l’Espai/Institut d’Estudis Espacials de Catalunya (CTE-CRAE/IEEC), Universitat Politècnica de Catalunya, 08034 Barcelona, Spain; (3) Atmospheric Research and Instrumentation Branch, Instituto Nacional de Técnica Aeroespacial (INTA), 28850 Torrejon de Ardoz, Spain; (4) Izaña Atmospheric Research Center, State Meteorological Agency of Spain (AEMET), 38001 Santa Cruz de Tenerife, Spain: (5) Code 612, Goddard Space Flight Center, National Aeronautics and Space Administration, Greenbelt, MD 20771, USA; (6) TRAGSATEC, 28006 Madrid, Spain; (7) Group of Atmospheric Optics, Universidad de Valladolid, 47011 Valladolid, SpainPostprint (published version

Volcanic eruption of Cumbre Vieja, La Palma, Spain: a first insight to the particulate matter injected in the troposphere

The volcanic eruption of Cumbre Vieja (La Palma Island, Spain), started on 19 September 2021 and was declared terminated on 25 December 2021. A complete set of aerosol measurements were deployed around the volcano within the first month of the eruptive activity. This paper describes the results of the observations made at Tazacorte on the west bank of the island where a polarized micro-pulse lidar was deployed. The analyzed two-and-a-half months (16 October–31 December) reveal that the peak height of the lowermost and strongest volcanic plume did not exceed 3 km (the mean of the hourly values is 1.43 0.45 km over the whole period) and was highly variable. The peak height of the lowermost volcanic plume steadily increased until week 11 after the eruption started (and 3 weeks before its end) and started decreasing afterward. The ash mass concentration was assessed with a method based on the polarization capability of the instrument. Two days with a high ash load were selected: The ash backscatter coefficient, aerosol optical depth, and the volume and particle depolarization ratios were, respectively, 3.6 (2.4) Mm. 1 sr. 1 , 0.52 (0.19), 0.13 (0.07) and 0.23 (0.13) on 18 October (15 November). Considering the limitation of current remote sensing techniques to detect large-to-giant particles, the ash mass concentration on the day with the highest ash load (18 October) was estimated to have peaked in the range of 800–3200 g m. 3 in the lowermost layer below 2.5 km.This research was funded by the Spanish Ministry of Science and Innovation (PID2020- 118793GA-I00, PID2019-104205GB-C21, EQC2018-004686-P and PID2019-103886RB-I00), the H2020 program from the European Union (GA no. 19ENV04, 654109, 778349, 871115 and 101008004), and the Unit of Excellence “María de Maeztu” (MDM-2017-0737) financed by the Spanish State Research Agency (AEI)

Vertical characterization of fine and coarse dust particles during an intense Saharan dust outbreak over the Iberian Peninsula in springtime 2021

An intense and long-lasting Saharan dust outbreak crossed the Iberian Peninsula (IP) from the southwest (SW) to the northeast (NE) from 25 March until 7 April 2021. This work aims to assess the optical and mass contribution of both fine and coarse dust particles along their transport. Five Iberian lidar stations were monitoring the transport and evolution of the Saharan dust particles, i.e. El Arenosillo/Huelva, Granada, Torrejón/Madrid and Barcelona in Spain, and Évora in Portugal. The particular meteorological conditions determined the aerosol scenario along the overall dust event, differing in the first part of the event (25–31 March), in which the strongest dust incidence occurred on 29–31 March at the south and central stations and 1 April at Barcelona, from the second one (1–7 April). The use of the two-step POLIPHON algorithm showed the relevance of using polarized lidar measurements for separating the aerosol properties of dust fine and coarse particles as an added value. Both the fine dust (Df) and coarse dust (Dc) components of the total particle backscatter coefficient (total dust, DD¿=¿Dc¿+¿Df) were separately derived. The dust plume was well-mixed with height and no significant differences were found in the vertical structure of both the Dc and Df particle backscatter coefficients. From the beginning of the dust outbreak until 1 April, the vertical Df¿¿DD mass ratio was nearly constant in time at each station and also in altitude with values of ~¿10¿%. Moreover, the mean dust optical depth at 532¿nm was decreasing along that dust pathway, reporting values from SW to NE stations of 0.34 at El Arenosillo/Huelva, 0.28 at Granada, 0.20 at Évora, 0.28 at Torrejón/Madrid, and 0.14 at Barcelona, although its Df¿¿DD ratio remained almost constant (28¿%–30¿%). A similar pattern was found for the total dust mass loading and its Df¿¿DD ratio, i.e. mostly decreasing mean mass values were reported, being constant in its Df¿¿DD ratio (~¿10¿%) along the SW–NE dust pathway. In addition, the episode-mean centre-of-mass height increased with latitude overall, showing a high variability, being greater than 0.5¿km at the southern sites (El Arenosillo/Huelva, Granada, Évora) and ~¿1.0¿km at Torrejón/Madrid and Barcelona. However, despite the relatively high intensity of the dust intrusion, the expected ageing of the dust particles was hardly observed, by taking into account the minor changes found in the contribution and properties of the coarse and fine dust particles. This is on the basis that the IP is relatively close to the Saharan dust sources and then, under certain dust transport conditions, any potential ageing processes in the dust particles remained unappreciated. The following must be highlighted: the different relative contribution of the fine dust particles to the total dust found for their optical properties (~¿30¿%) associated with the radiative effect of dust, with respect to that for the mass features (~¿10¿%) linked to air quality issues, along the overall dust event by crossing the IP.This research has been supported by the Spanish Ministry of Science and Innovation (grant no. PID2019-104205GB-C21/AEI/10.13039/501100011033).Peer ReviewedPostprint (published version

Characterization of Tajogaite volcanic plumes detected over the Iberian Peninsula from a set of satellite and ground-based remote sensing instrumentation

Three volcanic plumes were detected during the Tajogaite volcano eruptive activity (Canary Islands, Spain, September–December 2021) over the Iberian Peninsula. The spatiotemporal evolution of these events is characterised by combining passive satellite remote sensing and ground-based lidar and sun-photometer systems. The inversion algorithm GRASP is used with a suite of ground-based remote sensing instruments such as lidar/ ceilometer and sun-photometer from eight sites at different locations throughout the Iberian Peninsula. Satellite observations showed that the volcanic ash plumes remained nearby the Canary Islands covering a mean area of 120 ± 202 km2 during the whole period of eruptive activity and that sulphur dioxide plumes reached the Iberian Peninsula

Memoria del presidente y discurso del socio Sr. D. Adolfo Sicard y Pérez, leídos en la sesión solemne celebrada el día 24 de julio de 1892

Compilación de las memorias de la administración, tesorería y funcionamiento de la Sociedad San Vicente de Paul de Bogotá presentadas por el presidente de la institución, Vicente Restrepo, el 24 de julio de 1892. En la segunda parte del documento aparece el discurso pronunciado por Adolfo Sicard y Pérez, en calidad de socio de la institución. La ceremonia se llevó a cabo en la capilla del Colegio Mayor del Rosario.- Fiesta y sesión solemne de la Sociedad de San Vicente de Paúl. - Memoria presentada a la sociedad de San Vicente de Paúl, de Bogotá, por su presidente en la sesión solemne celebrada el 24 de Julio de 1892. - Parte del informe dirigido por S.S. el ministro de guerra al congreso de 1892, que se refiere a los talleres. - Discurso del socio señor D. Alfonso Sicard y Pérez

Summertine re-circulations of air pollutans over the north-eastern Iberian coast observed from systematic EARLINET lidar measurements in Barcelona

Regular aerosol backscatter measurements using an elastic-backscatter lidar were performed from May 2000 to December 2002 in Barcelona (Spain) in the frame of EU EARLINET Project (European Aerosol Research Lidar Network). Vertical profiles retrievedin a regular schedule confirmedthe presence of multiple aerosol layers of regional origin above the mixing layer during numerous measurement days. Analysis of the meteorological situation of the corresponding days showed common synoptic regimes, which are typical in summertime around the region. As documented by earlier studies, under strong insolation and weak synoptic forcing, sea breezes and mountain-induced winds develop to create re-circulations of pollutants along the eastern Iberian coast. Layers are formed when aerosols are injectedfrom the mountains into the return flow at various heights andd istances from the coast. Aerosol layers can be foundabove the mixing layer up to 4000m with variable thickness typically rangedbetween 100 and1000 m. The mixing height mainly oscillates between 400 and 800m asl in periods of maximum insolation. Four selected episodes are analysed combining lidar profiles, radiosoundings and synoptic meteorology information. One of them includes regional re-circulation aerosols at low levels andupper Saharan dust layers. Maximum backscatter coefficients ranged from 1 10 6 to 2 10 6 (m sr) 1 at the wavelength of 1064 nm. Assuming a lidar ratio of 30 sr (60 sr for Saharan dust), aerosol optical depths above the mixing layer ranged from 0.016 to 0.073. Detailed mesoscale analysis of one episode is performed by means of high resolution modelling with the PSU/NCAR Mesoscale Model 5 (MM5)

Determination of the mixing layer height from regular lidar measurements in the Barcelona area

Regular aerosol backscatter measurements using an elastic-backscatter lidar were performed between May 2000 and November 2002 in Barcelona (Spain), in the frame of EARLINET (European Aerosol Research Lidar Network). The mixing layer height, required to understand the chemical and physical processes taking place in the low troposphere, was one of the major parameters to be retrieved. Three analytic definitions of the ML height have been tested using the range squared-corrected lidar signal: (1) the minimum of its first derivative, (2) the minimum of its second derivative, and (3) the minimum of the first derivative of its logarithm. The strong coastal and orographic influences and the climatological settling of Barcelona determine the complexity of its atmospheric boundary layer dynamics and the high heterogeneity of the lidar signals. Therefore, single lidar analyses do not allow an unambiguous determination of the mixing layer height in many cases and complementary data are needed, such as synoptic maps, backtrajectories, radiosoundings and solar irradiance profiles. The resulting mixing layer heights were compared to radiosoundings, and the second method was found to give statistically the best results. This definition was used to process the whole dataset. A number of 162 days and 660 profiles were examined. The mixing layer height was inferred in cases such as low clouds, Saharan dust events and sea breeze and mountain induced recirculation. Variations between 300 and 1450 m were observed over the three years.The authors wish to acknowledge the following entities for partially supporting the research work and lidar systems developed at UPC: European Union under the EARLINET contract UE EVR1-CT-1999-40003, CICYT (Spanish Interministry Commission of Science and Technology) under the grants TIC 431/93, AMB96-1144-C02-C01, TIC99- 1050-C03-01, REN2000-1907-CE and REN2000-1754-C02-02/CLI, Spanish Ministry for Education and Culture under the Spanish-French Integrated Action HF1997-0212, and CIRIT (Interdepartmental Commission for Research and Technological Innovation, Generalitat de Catalunya) under the contract IMMPACTE. ESA is also thanked for the external postdoctoral fellowship allocated to M. Sicard.Peer ReviewedPostprint (published version