Three-dimensional distribution of Mount Etna’s emissions during the EPL-REFLECT campaign in July 2019

2021 ◽  
Author(s):  
Alessia Sannino ◽  
Antonella Boselli ◽  
Giuseppe Leto ◽  
Simona Scollo ◽  
Ricardo Zanmar Sanchez ◽  
...  
Keyword(s):  
Source Parameters ◽  
Three Dimensional ◽  
Mount Etna ◽  
Atmospheric Composition ◽  
Laser Source ◽  
Plume Dispersion ◽  
Essential Point ◽  
Field Campaign ◽  
Radiative Balance ◽  
Volcanic Aerosols

<p>Mount Etna (Italy) is the most high-impact volcanoes on Mediterranean scale mainly due to its eruptive activity and continuous passive degassing, and the inherent large amount of effluents released into the atmosphere. Mount Etna’s emission mainly originate from the summit craters at an altitude of about 3300 m, feeding frequently volcanic gases and aerosols into the free troposphere. Consequently, their effects on the atmosphere and regional climate system span over relatively long spatiotemporal scales.</p><p>In order to better understand the role that Mount Etna’s emissions play on the atmospheric composition and radiative balance in the Mediterranean area, multidisciplinary and multi-scale studies have been carried out since a few years within the different phases of the EtnaPlumeLab (EPL) research cluster. A part of the EPL effort is based on dedicated field campaigns, that aim at the characterization of volcanic sources emissions and nears-source plume dispersion and evolution.</p><p>In this work, we investigate the three-dimensional (3D) distribution of the volcanic aerosols from Mount Etna observed during the most recent EPL field campaign, named EPL-REFLECT (near-source estimations of Radiative EFfects of voLcanic aErosols for Climate and air quality sTudies) carried out within the Transnational Access component of the EUROVOLC project. This field campaign completes the previous EPL-RADIO (Radioactive Aerosols and other source parameters for better atmospheric Dispersion and Impact estimatiOns) campaign. Here we discuss the observations of a multiparametric LiDAR system AMPLE. The LiDAR is equipped with a fast scanning, double depolarization (at 532 and 355 nm) and high repetition laser source (1kHz), which is an essential point to derive time series of 3D-resolved aerosol properties near Etna. During the 8-12<sup>th</sup> of July 2019 period, day/night LiDAR measurements were performed by AMPLE from the astronomical observatory of the INAF-Catania in the location of Serra la Nave at 1725 m a.s.l., pointing towards the summit of Mount Etna. In particular, on the July 11<sup>th</sup>, the scan was performed with time-steps of 15 minutes at different angles from the top of the volcano to the zenith. These acquisitions highlight the atmospheric evolution of two layers related to two distinct degassing episodes. A comparative analysis with wind speed information and the integration with complementary photometric ground measurements have further constrained this 3D characterization and the evolution of these layers, including those outside the LiDAR field of view.</p>

The observation of different aerosols types in the Mount Etna environment and their relative and mutual impacts on local radiative balance

2021 ◽  
Author(s):  
Pasquale Sellitto ◽  
Giuseppe Salerno ◽  
Simona Scollo ◽  
Alcide Giorgio di Sarra ◽  
Antonella Boselli ◽  
...  
Keyword(s):  
Spatial Scales ◽  
Source Parameters ◽  
Mount Etna ◽  
Volcanic Plume ◽  
Dynamical Regime ◽  
Radiative Balance ◽  
Volcanic Aerosols ◽  
Aerosol Types ◽  
Lidar Observations

<p>The EPL-RADIO (Etna Plume Lab - Radioactive Aerosols and other source parameters for better atmospheric Dispersion and Impact estimatiOns) and EPL-REFLECT (near-source estimations of Radiative EFfects of voLcanic aErosols for Climate and air quality sTudies) projects, funded by the EC Horizon2020 ENVRIplus and EUROVOLC Transnational Access to European Observatories programmes, aim to advance the understanding of Mount Etna as a persistent source of atmospheric aerosols and its impact on the  radiative budget at proximal to regional spatial scales. Research was tackled by carrying out three campaigns in the summers of 2016, 2017 and 2019 to observe the volcanic plume produced by passive degassing, proximally and distally from the summit craters, using a wide array of remote sensing and in situ instruments. Diverse data are collected to explore the link of inner degassing mechanisms to the characterisation of near-source aerosol physicochemical properties and subsequent impacts on the atmosphere, environment and regional climate system.</p><p>The results of the three campaigns have shown that the volcanic plume emitted by Mount Etna often mixes with aerosols of different origins generating a complex layered pattern. Frequent mineral dust transport events were observed by both LiDAR observations located at Serra La Nave (~7 km south-west from summit craters) and at a medium-term radiometric station, equipped with a Multi-Filter Rotating Shadowband Radiometer (MFRSR), and other instruments located at Milo (~10 km eastwards from the craters). LiDAR observations also allowed to study the coexistence of volcanic aerosols and biomass burning particles from local to more distal smoke plumes transports (like for the well-documented large fires from continental southern Italy in July 2017). In situ filter and optical particles counter measurements confirmed the presence of dust at Milo. The interaction/mixing among volcanic, wildfire, and dust aerosols occurs in an overall dynamical regime which appears to be dominated by sea breeze, which is strengthened by the presence of the dark volcanic lava flanks. Photolysis process also possibly play a role in determining the daily evolution of the aerosol plume.</p><p>The sources of these different aerosol types are studied in detail using Lagrangian trajectories and meteorological data. Off-line radiative transfer calculations, using EPL-RADIO/REFLECT observations as input data, are used to estimate the relative radiative impact of the different aerosol types with respect to the background passive-degassing aerosols coming from Mount Etna.</p>

Simulating mixed-phase cloud properties with ICON around the CAPRICORN field campaign at the kilometre scale

2020 ◽  
Author(s):  
Veeramanikandan Ramadoss ◽  
Alain Protat ◽  
Yi Huang ◽  
Steven Siems ◽  
Anna Possner
Keyword(s):  
Southern Ocean ◽  
Climate Models ◽  
Cold Front ◽  
Meteorological Data ◽  
Short Wave ◽  
Atmospheric Composition ◽  
Wave Radiation ◽  
Limited Area ◽  
Field Campaign ◽  
Radiative Balance

<p>Stratocumulus clouds are low-level boundary layer clouds that cover 23% of the ocean surface on a global average, with a mean coverage of 25% to 40% in the mid-latitude oceans. These clouds affect Earth's radiative balance due to their strong radiative cooling effect. Many climate models underestimate the reflection of short wave radiation over the Southern Ocean (SO) which results in a positive mean bias of 2K in the annual mean SST in the mid-latitudes of the southern hemisphere. The organization, cloud field properties and the cloud radiative effects of these clouds occur at the lee of cold front in the SO are analyzed in this study. At this conference, we will present preliminary results.<br>Real case simulations are performed in this study by using ICON - LAM (Icosahedral Nonhydrostatic - Limited Area Model) with two-way nesting domains of resolutions 4.9 km to 2.4 km to 1.2 km. The initial and lateral boundary conditions for the model are derived from IFS meteorological data. CAPRICORN (Clouds, Aerosols, Precipitation, Radiation, and Atmospheric Composition over the Southern Ocean) field campaign that took place during March and April 2016 has continuously observed the open-cell and stratocumuli using shipborne radars and lidars on 26 and 27 March 2016 at the lee of a cold front between 47ºS 144ºE and 45ºS 146ºE (South of Tasmania). The results are evaluated quantitatively and qualitatively with the shipborne observations and HIMAWARI satellite retrievals respectively.</p>

scholarly journals Estimation of the compression strength and surface roughness of the as-built SLS components using weibull distribution

2021 ◽  
pp. 1-6
Author(s):  
Hamaid Mahmood KHAN
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Compressive Strength ◽  
Weibull Distribution ◽  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Random Variable ◽  
Production Quality ◽  
Laser Source ◽  
Distribution Method

Selective laser sintering (SLS) is a process of fabrication of three-dimensional structures by fus- ing powder particles using a guided laser source. The uncertainty in the mechanical properties of the SLS parts fabricated at the same time and with the same process parameters can affect the repeatability of the SLS process. A vast difference in the mechanical properties of the concurrently processed parts can lower the production quality of the batch. Therefore, the param- eters are required to be design based on the most probable outcome of the desired properties. Weibull distribution is one such statistical-based probability distribution method to measure the likelihood of the occurrence of a value of any random variable falling within a particular range of values. Here, the Weibull distribution was used to measure the relative likelihood (90% probability) of the surface roughness and the compressive strength values of the SLS-built polyamide PA2200 components in the given sample space that was obtained from 20 random samples. The results show that the variance in the surface roughness (scan and built plane) and the compressive strength values were in the range of 6–7 μm and around 10 MPa, respectively. Moreover, the surface roughness of the two orthogonal planes with 90% reliability was measured at 14.81 μm (scan plane) and 12.15 μm (built plane). Similarly, the yield strength and the compressive strength with 90% reliability were found 25.87 MPa and 62.64 MPa, respectively.

scholarly journals Key drivers of ozone change and its radiative forcing over the 21st century

2018 ◽  
Vol 18 (9) ◽  
pp. 6121-6139 ◽  
Author(s):  
Fernando Iglesias-Suarez ◽  
Douglas E. Kinnison ◽  
Alexandru Rap ◽  
Amanda C. Maycock ◽  
Oliver Wild ◽  
...  
Keyword(s):  
Climate Change ◽  
21St Century ◽  
Radiative Forcing ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Atmospheric Composition ◽  
Climate Conditions ◽  
Radiative Balance ◽  
Radiative Forcings ◽  
Year 2000

Abstract. Over the 21st century changes in both tropospheric and stratospheric ozone are likely to have important consequences for the Earth's radiative balance. In this study, we investigate the radiative forcing from future ozone changes using the Community Earth System Model (CESM1), with the Whole Atmosphere Community Climate Model (WACCM), and including fully coupled radiation and chemistry schemes. Using year 2100 conditions from the Representative Concentration Pathway 8.5 (RCP8.5) scenario, we quantify the individual contributions to ozone radiative forcing of (1) climate change, (2) reduced concentrations of ozone depleting substances (ODSs), and (3) methane increases. We calculate future ozone radiative forcings and their standard error (SE; associated with inter-annual variability of ozone) relative to year 2000 of (1) 33 ± 104 m Wm−2, (2) 163 ± 109 m Wm−2, and (3) 238 ± 113 m Wm−2 due to climate change, ODSs, and methane, respectively. Our best estimate of net ozone forcing in this set of simulations is 430 ± 130 m Wm−2 relative to year 2000 and 760 ± 230 m Wm−2 relative to year 1750, with the 95 % confidence interval given by ±30 %. We find that the overall long-term tropospheric ozone forcing from methane chemistry–climate feedbacks related to OH and methane lifetime is relatively small (46 m Wm−2). Ozone radiative forcing associated with climate change and stratospheric ozone recovery are robust with regard to background climate conditions, even though the ozone response is sensitive to both changes in atmospheric composition and climate. Changes in stratospheric-produced ozone account for ∼ 50 % of the overall radiative forcing for the 2000–2100 period in this set of simulations, highlighting the key role of the stratosphere in determining future ozone radiative forcing.

scholarly journals Stratospheric ozone depletion during the 1995–1996 Arctic winter: 3-D simulations on the potential role of different PSC types

2001 ◽  
Vol 19 (9) ◽  
pp. 1163-1181 ◽  
Author(s):  
J. Hendricks ◽  
F. Baier ◽  
G. Günther ◽  
B. C. Krüger ◽  
A. Ebel
Keyword(s):  
Ozone Depletion ◽  
Middle Atmosphere ◽  
Spatial Scales ◽  
Stratospheric Ozone ◽  
Three Dimensional ◽  
Particle Growth ◽  
Atmospheric Composition ◽  
Formation Mechanisms ◽  
Three Dimensional Model ◽  
Type Ia

Abstract. The sensitivity of modelled ozone depletion in the winter Arctic stratosphere to different assumptions of prevalent PSC types and PSC formation mechanisms is investigated. Three-dimensional simulations of the winter 1995/96 are performed with the COlogne Model of the Middle Atmosphere (COMMA) by applying different PSC microphysical schemes. Model runs are carried out considering either liquid or solid PSC particles or a combined microphysical scheme. These simulations are then compared to a model run which only takes into account binary sulfate aerosols. The results obtained with the three-dimensional model agree with trajectory-box simulations performed in previous studies. The simulations suggest that conditions appropriate for type Ia PSC existence (T < TNAT ) occur over longer periods and cover larger areas when compared to conditions of potential type Ib PSC existence. Significant differences in chlorine activation and ozone depletion occur between the simulations including only either liquid or solid PSC particles. The largest differences, occurring over large spatial scales and during prolonged time periods, are modelled first, when the stratospheric temperatures stay below TNAT , but above the threshold of effective liquid particle growth and second, in the case of the stratospheric temperatures remaining below this threshold, but not falling below the ice frost point. It can be generally concluded from the present study that differences in PSC microphysical schemes can cause significant fluctuations in ozone depletion modelled for the winter Arctic stratosphere.Key words. Atmospheric composition and structure (aerosols and particles; cloud physics and chemistry; middle atmosphere composition and chemistry)

scholarly journals Application of laser remote sensing technology and super continuous spectrum laser

2020 ◽  
Vol 165 ◽  
pp. 03002
Author(s):  
Li Jing ◽  
Che Ying ◽  
Jin Meishan ◽  
Zhai Yannan ◽  
Ding Changhong
Keyword(s):  
Remote Sensing ◽  
Continuous Spectrum ◽  
Oil Spill ◽  
Three Dimensional ◽  
High Energy ◽  
High Energy Density ◽  
Laser Radar ◽  
Laser Source ◽  
Spectral Information ◽  
Distant Target

Fiber optic super continuous spectrum laser technology is a new technology developed in recent years. It takes into account the advantages of good alignment of laser source, high energy density and wide wavelength range of ordinary white light source, which can not only accurately remote sense distant target, but also obtain hyperspectral information of distant target. Super continuous spectrum of laser radar is a kind of remote sensing monitoring instrument, it can obtain three-dimensional spectral information of the target, and can be accurately detected in the night of distant high spectral information, the all-weather, three-dimensional spectrum detection method with the traditional passive remote sensing compared with single/multiband laser radar technology has incomparable advantages. Based on the development trend of lidar abroad, the development status of super-continuous spectrum lidar in China and the problems in remote sensing detection of oil spill, this paper introduces the feasibility of using super-continuous spectrum laser to monitor oil spill in the sea, which lays a foundation for further research.

scholarly journals Vertical circulation and thermospheric composition: a modelling study

1999 ◽  
Vol 17 (6) ◽  
pp. 794-805 ◽  
Author(s):  
H. Rishbeth ◽  
I. C. F. Müller-Wodarg
Keyword(s):  
Concentration Ratio ◽  
Atomic Oxygen ◽  
Molecular Nitrogen ◽  
Three Dimensional ◽  
Atmospheric Composition ◽  
Vertical Circulation ◽  
Energy Inputs ◽  
Composition And Structure ◽  
Vertical Distributions ◽  
Summer Hemisphere

Abstract. The coupled thermosphere-ionosphere-plasmasphere model CTIP is used to study the global three-dimensional circulation and its effect on neutral composition in the midlatitude F-layer. At equinox, the vertical air motion is basically up by day, down by night, and the atomic oxygen/molecular nitrogen [O/N2] concentration ratio is symmetrical about the equator. At solstice there is a summer-to-winter flow of air, with downwelling at subauroral latitudes in winter that produces regions of large [O/N2] ratio. Because the thermospheric circulation is influenced by the high-latitude energy inputs, which are related to the geometry of the Earth's magnetic field, the latitude of the downwelling regions varies with longitude. The downwelling regions give rise to large F2-layer electron densities when they are sunlit, but not when they are in darkness, with implications for the distribution of seasonal and semiannual variations of the F2-layer. It is also found that the vertical distributions of O and N2 may depart appreciably from diffusive equilibrium at heights up to about 160 km, especially in the summer hemisphere where there is strong upwelling. Atmospheric composition and structure (thermosphere · composition and chemistry) · Ionosphere (ionosphere · atmosphere interactions)

Control-Oriented Modeling and Repetitive Control in In-Layer and Cross-Layer Thermal Interactions in Selective Laser Sintering

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Dan Wang ◽  
Tianyu Jiang ◽  
Xu Chen
Keyword(s):  
High Performance ◽  
Selective Laser Sintering ◽  
Repetitive Control ◽  
Three Dimensional ◽  
Process Variations ◽  
Laser Sintering ◽  
Laser Source ◽  
Cross Layer ◽  
Modeling And Control ◽  
Melt Pool

Abstract Although laser-based additive manufacturing (AM) has enabled unprecedented fabrication of complex parts directly from digital models, broader adoption of the technology remains challenged by insufficient reliability and in-process variations. In pursuit of assuring quality in the selective laser sintering (SLS) AM, this paper builds a modeling and control framework of the key thermodynamic interactions between the laser source and the materials to be processed. First, we develop a three-dimensional finite element simulation to understand the important features of the melt pool evolution for designing sensing and feedback algorithms. We explore how the temperature field is affected by hatch spacing and thermal properties that are temperature-dependent. Based on high-performance computer simulation and experimentation, we then validate the existence and effect of periodic disturbances induced by the repetitive in- and cross-layer thermomechanical interactions. From there, we identify the system model from the laser power to the melt pool width and build a repetitive control algorithm to greatly attenuate variations of the melt pool geometry.

scholarly journals Transient Model for CW and Pulsed Laser Machining of Ablating/Decomposing Materials—Approximate Analysis

1996 ◽  
Vol 118 (3) ◽  
pp. 774-780 ◽  
Author(s):  
M. F. Modest
Keyword(s):  
Three Dimensional ◽  
Pulsed Laser ◽  
Computer Time ◽  
Single Step ◽  
Laser Source ◽  
Laser Machining ◽  
Transient Model ◽  
One Dimensional ◽  
Cpu Time ◽  
Order Of Magnitude

Approximate, quasi-one-dimensional conduction models have been developed to predict the changing shape of holes, single grooves, or overlapping grooves carved by ablation into a thick solid that is irradiated by a moving laser source. For CW or pulsed laser operation a simple integral method is presented, which predicts shapes and removal rates with an accuracy of a few percent, while requiring one order of magnitude less CPU time than a three-dimensional, numerical solution. For pulsed operation a “full-pulse” model is presented, computing the erosion from an entire pulse in a single step, and reducing computer time by another order of magnitude.

Sign in / Sign up

Export Citation Format

Share Document