Suchergebnisse

In this paper, is presented a method for estimation of the effect of the transport process to aerosol optical properties. Aerosol optical data retrieved by lidars and sun-photometer measurements, are applied to Saharan dust events observed simultaneously at the two EARLINET/AERONET sites of Barcelona and Granada during the periods of June–September of 2012 and 2013. For this purpose, elastic lidar profiles and sun-photometer columnar retrievals are analyzed together with satellite observations and dust forecast models. Granada presents more than twice Saharan dust outbreaks compared to Barcelona. The scenarios favoring the Saharan dust outbreaks are identified in both places. The mineral dust originating in the Sahara region and arriving at both stations is usually transport wither over the Atlas Mountains or through an Atlantic pathway. Analyses of dust events affecting both stations reveal how differences in the transport process lead to differences in the aerosol optical properties measured at each station. Mean dust related Ångström exponent is 1.8 times higher in Barcelona than in Granada. This difference is a result of the additional contribution of anthropogenic aerosol, mainly in the aerosol fine mode, during the transport of the mineral dust plume over the Iberian Peninsula. ; Andalusia Regional Government through the project P12-RNM-2409 ; Spanish Ministry of Economy and Competitiveness through the project CGL2013-45410-R

During the 2017 record-breaking burning season in Canada/United States, intense wild fires raged during the first week of September in the Pacific northwestern region (British Columbia, Alberta, Washington, Oregon, Idaho, Montana and northern California) burning mostly temperate coniferous forests. The heavy loads of smoke particles emitted in the atmosphere reached the Iberian Peninsula (IP) a few days later on 7 and 8 September. Satellite imagery allows to identify two main smoke clouds emitted during two different periods that were injected and transported in the atmosphere at several altitude levels. Columnar properties on 7 and 8 September at two Aerosol Robotic Network (AERONET) mid-altitude, background sites in northern and southern Spain are: aerosol optical depth (AOD) at 440 nm up to 0.62, Ångström exponent of 1.6–1.7, large dominance of small particles (fine mode fraction >0.88), low absorption AOD at 440 nm (0.98). Profiles from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) show the presence of smoke particles in the stratosphere during the transport, whereas the smoke is only observed in the troposphere at its arrival over the IP. Portuguese and Spanish ground lidar stations from the European Aerosol Research Lidar Network/Aerosols, Clouds, and Trace gases Research InfraStructure Network (EARLINET/ACTRIS) and the Micro-Pulse Lidar NETwork (MPLNET) reveal smoke plumes with different properties: particle depolarization ratio and color ratio, respectively, of 0.05 and 2.5 in the mid troposphere (5–9 km) and of 0.10 and 3.0 in the upper troposphere (10–13 km). In the mid troposphere the particle depolarization ratio does not seem time-dependent during the transport whereas the color ratio seems to increase (larger particles sediment first). To analyze the horizontal and vertical transport of the smoke from its origin to the IP, particle dispersion modelling is performed with the Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) parameterized with satellite-derived biomass burning emission estimates from the Global Fire Assimilation System (GFAS) of the Copernicus Atmosphere Monitoring Service (CAMS). Three compounds are simulated: carbon monoxide, black carbon and organic carbon. The results show that the first smoke plume which travels slowly reaches rapidly (~1 day) the upper troposphere and lower stratosphere (UTLS) but also shows evidence of large scale horizontal dispersion, while the second plume, entrained by strong subtropical jets, reaches the upper troposphere much slower (~2.5 days). Observations and dispersion modelling all together suggest that particle depolarization properties are enhanced during their vertical transport from the mid to the upper troposphere. ; Spanish groups acknowledge the Spanish Ministry of Economy and Competitivity (MINECO) (ref. CGL2013-45410-R, CGL2014-52877-R, CGL2014-55230-R, TEC2015-63832-P, CGL2015-73250-JIN, CGL2016-81092-R and CGL2017-85344-R) ; European Union through H2020 programme ACTRIS-2, grant 654109 ; European Union through H2020 programme EUNADICS-AV, grant 723986 ; European Union through H2020 programme GRASP-ACE, grant 778349

During the ADRIMED (Aerosol Direct Radiative Impact on the regional climate in the Mediterranean region) special observation period (SOP-1a), conducted in June 2013 in the framework of the ChArMEx (Chemistry-Aerosol Mediterranean Experiment) project, a moderate Saharan dust event swept the Western and Central Mediterranean Basin (WCMB) from west to east during a 9-day period between 16 and 24 June. This event was monitored from the ground by six EARLINET/ACTRIS (European Aerosol Research Lidar Network/Aerosols, Clouds, and Trace gases Research Infrastructure Network) lidar stations (Granada, Barcelona, Naples, Potenza, Lecce and Serra la Nave) and two ADRIMED/ChArMEx lidar stations specially deployed for the field campaign in Cap d'en Font and Ersa, in Minorca and Corsica Islands, respectively. The first part of the study shows the spatio-temporal monitoring of the dust event during its transport over the WCMB with ground-based lidar and co-located AERONET (Aerosol Robotic Network) Sun-photometer measurements. Dust layer optical depths, Ångström exponents, coarse mode fractions, linear particle depolarization ratios (LPDRs), dust layer heights and the dust radiative forcing estimated in the shortwave (SW) and longwave (LW) spectral ranges at the bottom of the atmosphere (BOA) and at the top of the atmosphere (TOA) with the Global Atmospheric Model (GAME), have been used to characterize the dust event. Peak values of the AERONET aerosol optical depth (AOD) at 440 nm ranged between 0.16 in Potenza and 0.37 in Cap d'en Font. The associated Ångström exponent and coarse mode fraction mean values ranged from 0.43 to 1.26 and from 0.25 to 0.51, respectively. The mineral dust produced a negative SW direct radiative forcing at the BOA ranging from −56.9 to −3.5 W m−2. The LW radiative forcing at the BOA was positive, ranging between +0.3 and +17.7 W m-2. The BOA radiative forcing estimates agree with the ones reported in the literature. At the TOA, the SW forcing varied between −34.5 and +7.5 W m−2. In seven cases, the forcing at the TOA resulted positive because of the aerosol strong absorbing properties (0.83 < single-scattering albedo (SSA) < 0.96). The multi-intrusion aspect of the event is examined by means of air- and space-borne lidar measurements, satellite images and back trajectories. The analysis reported in this paper underline the arrival of a second different intrusion of mineral dust observed over southern Italy at the end of the considered period which probably results in the observed heterogeneity in the dust properties. ; Spanish Ministry of Economy and Competitiveness (project TEC2012-34575 and TEC2015-63832-P) ; Science and Innovation (project UNPC10-4E-442) ; Andalusia Regional Government through projects P12-RNM-2409 and P10-RNM-6299

Systematic measurements of dust concentration profiles at a continental scale were recently made possible by the development of synergistic retrieval algorithms using combined lidar and sun photometer data and the establishment of robust remote-sensing networks in the framework of Aerosols, Clouds, and Trace gases Research InfraStructure Network (ACTRIS)/European Aerosol Research Lidar Network (EARLINET). We present a methodology for using these capabilities as a tool for examining the performance of dust transport models. The methodology includes considerations for the selection of a suitable data set and appropriate metrics for the exploration of the results. The approach is demonstrated for four regional dust transport models (BSC-DREAM8b v2, NMMB/BSC-DUST, DREAMABOL, DREAM8-NMME-MACC) using dust observations performed at 10 ACTRIS/EARLINET stations. ; The financial support of the ACTRIS Research Infrastructure Project supported by the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 262254 is gratefully acknowledged. This project has also received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 289923 – ITaRS. S. Basart and J. M. Baldasano acknowledge the CICYT project (CGL2010-19652 and CGL2013-46736) and Severo Ochoa (SEV- 2011-00067) programme of the Spanish Government. This program has received funding from the Ministry of Education and Science of the Republic of Serbia through project III43007.

Systematic measurements of dust concentration profiles at a continental scale were recently made possible by the development of synergistic retrieval algorithms using combined lidar and sun photometer data and the establishment of robust remote-sensing networks in the framework of Aerosols, Clouds, and Trace gases Research InfraStructure Network (ACTRIS)/European Aerosol Research Lidar Network (EARLINET). We present a methodology for using these capabilities as a tool for examining the performance of dust transport models. The methodology includes considerations for the selection of a suitable data set and appropriate metrics for the exploration of the results. The approach is demonstrated for four regional dust transport models (BSC-DREAM8b v2, NMMB/BSC-DUST, DREAMABOL, DREAM8-NMME-MACC) using dust observations performed at 10 ACTRIS/EARLINET stations. ; The financial support of the ACTRIS Research Infrastructure Project supported by the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 262254 is gratefully acknowledged. This project has also received funding from the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 289923 – ITaRS. S. Basart and J. M. Baldasano acknowledge the CICYT project (CGL2010-19652 and CGL2013-46736) and Severo Ochoa (SEV- 2011-00067) programme of the Spanish Government. This program has received funding from the Ministry of Education and Science of the Republic of Serbia through project III43007.