scholarly journals Diagnosis of the Relationship between Dust Storms over the Sahara Desert and Dust Deposit or Coloured Rain in the South Balkans

2010 ◽  
Vol 2010 ◽  
pp. 1-14 ◽  
Author(s):  
N. G. Prezerakos ◽  
A. G. Paliatsos ◽  
K. V. Koukouletsos
Keyword(s):  
Atmospheric Circulation ◽  
Dust Cloud ◽  
Dust Storms ◽  
Dust Particles ◽  
Sahara Desert ◽  
Synoptic Scale ◽  
Yellow Colour ◽  
Western Sahara ◽  
Sand Storm ◽  
Dust Deposits

The main objects of study in this paper are the synoptic scale atmospheric circulation systems associated with the rather frequent phenomenon of coloured rain and the very rare phenomenon of dust or sand deposits from a Saharan sandstorm triggered by a developing strong depression. Analysis of two such cases revealed that two days before the occurrence of the coloured rain or the dust deposits over Greece a sand storm appeared over the north-western Sahara desert. The flow in the entire troposphere is southerly/south-westerly with an upward vertical motion regime. If the atmospheric conditions over Greece favour rain then this rain contains a part of the dust cloud while the rest is drawn away downstream adopting a light yellow colour. In cases where the atmospheric circulation on the route of the dust cloud trajectories is not intensively anticyclonic dust deposits can occur on the surface long far from the region of the dust origin. Such was the case on 4th April, 1988, when significant synoptic-scale subsidence occurred over Italy and towards Greece. The upper air data, in the form of synoptic maps, illustrate in detail the synoptic-scale atmospheric circulations associated with the emission-transport-deposition and confirm the transportation of dust particles.

scholarly journals Asian Dust properties investigated by multi-instruments

2019 ◽  
Vol 99 ◽  
pp. 02003
Author(s):  
Janbai Nee
Keyword(s):  
Remote Sensing ◽  
Dust Cloud ◽  
Asian Dust ◽  
Dust Storms ◽  
Dust Particles ◽  
Atmospheric Processes ◽  
Aerosol Sources ◽  
Dust Events ◽  
Aerosol Cloud Interactions ◽  
Lidar Observations

Dust and many types of aerosols are major pollutants significantly affecting the environment in the East Asia. To identify and classify various types of aerosols is a challenge. In Taiwan and nearby areas, Asian Dust mainly arrive in spring with an average of about 5 dust storms each year. They usually come with some other aerosol sources, therefore it is important to identify these aerosols and their properties. In this paper, we report studying of dust aerosols by using several ground-based and remote sensing measurements. The AERONET data is used to find optical properties of aerosols in 2008-2012. The lidar observations can investigate further properties and atmospheric processes for specific dust events, including observations of aerosol-cloud interactions. These combined with model or space observations can help us to understand long range dust particles transported to distant areas and their interaction with weather systems. A real time case of observation of dust-cloud interaction is provided.

Modelling an exceptional desert dust transport toward Portugal on February 2017

2020 ◽  
Author(s):  
Maria João Costa ◽  
Flavio Couto ◽  
Eduardo Cardoso ◽  
Rui Salgado ◽  
Juan Luis Guerrero-Rascado
Keyword(s):  
Iberian Peninsula ◽  
Atmospheric Circulation ◽  
Dust Emission ◽  
Horizontal Resolution ◽  
Sahara Desert ◽  
Dust Transport ◽  
Western Sahara ◽  
Orographic Effects ◽  
Desert Dust ◽  
The North

<p>The terrain surrounding the Sahara desert is formed by some mountains ranges, as the Atlas mountain system in the northern edge of the desert and the Hoggar Mountains in Southern Algeria. Such orography, jointly with atmospheric circulation, plays an important role in the mobilization and transport of desert dust over medium and large distances. This study explores the interaction between complex terrain and atmospheric circulation in order to better understand an exceptional desert dust outbreak affecting Portugal in February 2017. The Meso-NH model is able to represent the atmospheric motions in different scales, and has been implemented with a rather complete parametrization package of physical processes in the atmosphere. The capability of the model to simulate dust emission is also explored. The on-line dust emission parametrization type is taken from the distribution of emitted dust of SURFEX with no need to use chemistry to activate dusts. A set of two simulations was performed for the period between 16 February at 0000 UTC to 24 February 1200 UTC, with the Meso-NH model configured in a single domain at 10 km horizontal resolution and 300x360 grid points. The experiments were defined as a) control experiment (CTRL), and b) dust experiment (DUST). From the large domain simulations, it was possible to assess the source of dust and its mobilization over Western Sahara desert, namely over the Northern part of Mauritania and Mali and Eastern part of Algeria. The formation of a cyclonic circulation at the surface favoured the dust uplifting. Such a surface low merged with a cut-off low that moved southward over the Iberian Peninsula and remained centred in the north of Morocco. Such pattern intensified the northward flow found at 700 hPa toward the Atlas Mountains range, inducing the dust transport above 3 km altitude. As expected, the simulations showed the ability to assess important details about the atmospheric circulation not resolved by low density of observations over the domain considered. Furthermore, the simulations were able to show the way that the atmospheric ingredients were brought together to produce the exceptional transport of desert dust toward Portugal. The orographic effects playing an important role in dust mobilization (convergence and cyclogenesis at the surface) and atmospheric circulation to the maintenance of the dust transport have been highlighted. Such event were responsible for the transport of high amount of dust toward the Iberian Peninsula.</p>

Impact of dust and sand storms on the aviation operation and assessment of conditions for their occurrence at aerodromes in European Russia

2020 ◽  
Vol 4 ◽  
pp. 78-95
Author(s):  
A.R. Ivanova ◽  
◽  
E.N. Skriptunova ◽  
N.I. Komasko ◽  
A.A. Zavialova ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Dust Storms ◽  
European Russia ◽  
Air Transport ◽  
Review Of Literature ◽  
Dust Transport ◽  
Air Masses ◽  
The Past ◽  
Sand Storm ◽  
The Impact

A review of literature on the impact of dust and sand storms on the air transport operation is presented. Observational data on dust storms at the aerodromes of European Russia for the period of 2001-2019 are analyzed. The seasonal variations in dust transport episodes at aerodromes and its relationship with visibility changes are discussed. The characteristics of dusty air masses and advection are given. It is concluded that the frequency of dust transfer episodes for the aerodromes under study has decreased over the past five years, except for Gumrak aerodrome (Volgograd). Keywords: dust storm, sand storm, aviation, visibility, seasonal variations, aerodrome оf European Russia

Simulation and analysis of synoptic scale dust storms over the Arabian Peninsula

2018 ◽  
Vol 199 ◽  
pp. 62-81 ◽  
Author(s):  
S. Naseema Beegum ◽  
Imen Gherboudj ◽  
Naira Chaouch ◽  
Marouane Temimi ◽  
Hosni Ghedira
Keyword(s):  
Arabian Peninsula ◽  
Dust Storms ◽  
Synoptic Scale

scholarly journals Giant dust particles at Nevado Illimani: a proxy of summertime deep convection over the Bolivian Altiplano

2021 ◽  
Vol 15 (3) ◽  
pp. 1383-1397
Author(s):  
Filipe G. L. Lindau ◽  
Jefferson C. Simões ◽  
Barbara Delmonte ◽  
Patrick Ginot ◽  
Giovanni Baccolo ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Stable Isotope ◽  
Atmospheric Circulation ◽  
Meteorological Data ◽  
Deep Convection ◽  
Relative Proportion ◽  
Dust Particles ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Convective Activity

Abstract. A deeper understanding of past atmospheric circulation variability in the Central Andes is a high-priority topic in paleoclimatology mainly because of the necessity to validate climate models used to predict future precipitation trends and to develop mitigation and/or adaptation strategies for future climate change scenarios in this region. Within this context, we here investigate an 18-year firn core drilled at Nevado Illimani in order to interpret its mineral dust record in relation to seasonal processes, in particular atmospheric circulation and deep convection. The core was dated by annual layer counting based on seasonal oscillations of dust, calcium, and stable isotopes. Geochemical and mineralogical data show that dust is regionally sourced in winter and summer. During austral summer (wet season), an increase in the relative proportion of giant dust particles (∅>20 µm) is observed, in association with oscillations of stable isotope records (δD, δ18O). It seems that at Nevado Illimani both the deposition of dust and the isotopic signature of precipitation are influenced by atmospheric deep convection, which is also related to the total amount of precipitation in the area. This hypothesis is corroborated by regional meteorological data. The interpretation of giant particle and stable isotope records suggests that downdrafts due to convective activity promote turbulent conditions capable of suspending giant particles in the vicinity of Nevado Illimani. Giant particles and stable isotopes, when considered together, can be therefore used as a new proxy for obtaining information about deep convective activity in the past.

scholarly journals Estimating the Asteroidal Component of the Zodiacal Cloud using the Earth's Resonant Ring

1996 ◽  
Vol 150 ◽  
pp. 155-158 ◽  
Author(s):  
Sumita Jayaraman ◽  
Stanley F. Dermott
Keyword(s):  
Surface Area ◽  
Frequency Distribution ◽  
Size Range ◽  
Dust Cloud ◽  
Dust Particles ◽  
Direct Function ◽  
Size Frequency Distribution ◽  
Limited Size ◽  
Zodiacal Cloud ◽  
Asteroidal Dust

AbstractThe Earth's resonant ring is populated primarily by asteroidal dust particles because cometary particles have higher Poynting-Robertson drag rates and the Earth's resonances are not strong enough to trap them (Gomes, 1995). It has been shown that asteroidal particles in a limited size range from 5 — 30μm are responsible for the observed trailing/leading flux asymmetry caused by the trailing dust cloud embedded in the ring (Jayaraman and Dermott 1995). The magnitude of the flux asymmetry is a direct function of the area of dust in the ring, which in turn depends upon the number of asteroidal particles in the zodiacal cloud. Using a dynamical model of the ring and the background zodiacal cloud and estimating the surface area of dust needed in the ring to match the observed flux asymmetry in the 25 micron COBE waveband, we have calculated the fraction of asteroidal dust in the zodiacal cloud as a function of p, the slope of the size-frequency distribution of particles.

scholarly journals Cart-ruts in Lanzarote (Canary Islands, Spain) volcanoes tops point to Equinoxes, Summer and Winter Solstices

2020 ◽  
Vol 2 (13) ◽  
pp. 123-138
Author(s):  
Antonio Arnaiz-Villena ◽  
Marcial Medina ◽  
Valentín Ruiz-del-Valle ◽  
Adrian Lopez-Nares ◽  
Julian Rodriguez-Rodriguez ◽  
...  
Keyword(s):  
Bronze Age ◽  
Canary Islands ◽  
Mediterranean Basin ◽  
Sahara Desert ◽  
African Countries ◽  
Western Sahara ◽  
Azores Archipelago ◽  
Cultural Traits ◽  
Probability Methods ◽  
European Investment

Cart-ruts have been observed in Mediterranean Basin, Eurasia and Africa. They are rock carved stripes and channels which unexpectedly converge and/or bend, not being useful for transportation use because constant parallelism is not kept. Cart-ruts came first to scholars attention in Malta and Gozo Islands where they are abundant and dated at Bronze or Temple Age of this Archipelago. A big conjoint European investment for Cart-ruts study only got a detailed inventory in several Eurasian and African countries. Age and use of Cart-ruts remains non-discovered: it is admitted that different ages and uses may not be the same for different or even same areas. Azores Archipelago Cart-ruts were left out of this study and we have recently described them at Lanzarote (Canary Islands, Spain) volcanoes tops and slopes and suggested that they could have been useful for space and time measurements. In the present study, Lanzarote is studied and Mt. Mina and Mt. Guardilama mountains Cart-ruts azimuths points to Summer and Winter Solstices sunrises respectively as measured from Quesera/”Cheeseboard” of Zonzamas, which is a prehistoric Guanche lunisolar calendar. Mt. Tenezara Cart-ruts azimuth is pointing towards Equinoxes sunrises, as observed from Zonzamas prehistoric calendar. Thus, a use for measure time and space could be a function for some Lanzarote Cart-ruts. We explain these findings in a prehistoric Guanche aborigine culture context probably common to Atlantic megalithic Bronze Age and to all Canary Islands having prehistoric inter-navigation, because all have similar rock Iberian-Guanche inscriptions and other common cultural traits. Sahara Desert abandoning by people also influenced Mediterranean and Atlantic culture. Probability that 3 out of 7 studied volcano Cart-ruts point to Solstices and Equinoxes by chance is close to zero as calculated by factorial probability methods. Keywords: Latin, Scripts, Canary Islands, Iberian, Guanche, Lanzarote, Fuerteventura, Quesera-Cheeseboard, Pyramids, Berber, Africa, Punic, Roman, Western Sahara, Tunisia, Canaria, Calendar, Etruscan, Basque, Cart-ruts, Usko-Mediterranean, Solstice, Equinox, Zonzamas, HLA, Genetics, Sahara. Atchano, Malta

scholarly journals Effects of three-dimensional electric field on saltation during dust storms: An observational and numerical study

2019 ◽  
Author(s):  
Huan Zhang ◽  
You-He Zhou
Keyword(s):  
Electric Field ◽  
Field Data ◽  
Numerical Study ◽  
Three Dimensional ◽  
Vertical Component ◽  
Dust Storms ◽  
Dust Particles ◽  
Sand Transport ◽  
Dust Transport ◽  
Dust Events

Abstract. Particle tribo-electrification being ubiquitous in nature and industry, potentially plays a key role in dust events, including the lifting and transport of sand and dust particles. However, the properties of electric field (E-field) and its influences on saltation during dust storms remain obscure as the high complexity of dust storms and the existing numerical studies mainly limited to one-dimensional (1-D) E-field. Here, we quantify the effects of real three-dimensional (3-D) E-field on saltation, through a combination of field observations and numerical modelling. The 3-D E-fields in the sub-meter layer from 0.05 to 0.7 m above the ground during a dust storm are measured at Qingtu Lake Observation Array site. The measured results show that each component of the 3-D E-field data nearly collapses on a single 3-order polynomial curve when normalized. Interestingly, the vertical component of the 3-D E-field increases with increasing height in the saltation layer during dust storms. Such 3-D E-field data close to the ground within a few centimeters has never been reported and formulated before. Using the discrete element method, we then develop a comprehensive saltation model, in which the tribo-electrification between particle-particle midair collisions is explicitly accounted for, allowing us to evaluate the tribo-electrification in saltation properly. By combining the results of measurements and modelling, we find that although the vertical component of the E-field (i.e. 1-D E-field) inhibits sand transport, 3-D E-field enhances sand transport substantially. Furthermore, the model predicts that 3-D E-field enhances the total mass flux by up to 63 %. This suggests that a truly 3-D E-field consideration is necessary if one is to explain precisely how the E-field affects saltation during dust storms. These results will further improve our understanding of particle tribo-electrification in saltation and help to provide more accurate characterizations of sand and dust transport during dust storms.

scholarly journals Numerical simulations of windblown dust over complex terrain: The Fiambalá Basin episode in June 2015

2016 ◽  
Author(s):  
Leonardo A. Mingari ◽  
Estela A. Collini ◽  
Arnau Folch ◽  
Walter Báez ◽  
Emilce Bustos ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Long Range ◽  
Complex Terrain ◽  
Volcanic Ash ◽  
Dust Cloud ◽  
Temporal Distribution ◽  
Dust Particles ◽  
Long Range Transport ◽  
Mountain Range ◽  
Range Transport

Abstract. On the 13 June 2015, the London Volcanic Ash Advisory Centre (VAAC) warned the Buenos Aires VAAC about a possible volcanic eruption from the Nevados Ojos del Salado volcano (6879 m), located in the Andes mountain range on the border between Chile and Argentina. A volcanic ash cloud was detected by the SEVIRI instrument on board the Meteosat Second Generation (MSG) satellites from 14:00 UTC on 13 June. Further studies concluded that the phenomenon was caused by remobilization of ancient pyroclastic deposits (circa 4.5 Ka Cerro Blanco eruption) from the Bolsón de Fiambalá (Fiambalá Basin) in northwestern Argentina. In this paper, we provide the first comprehensive description of the dust episode through observations and numerical simulations. We have investigated the spatio-temporal distribution of aerosols and the emission process over complex terrain to gain insight into the key role played by the orography and the condition that triggered the long-range transport episode. Numerical simulations of windblown dust were performed using the WRF-ARW/FALL3D modeling system with meteorological fields downscaled to a spatial resolution of 2 km in order to resolve the complex orography of the area. Results indicated that favourable conditions to generate dust uplifting occurred in northern Fiambalá Basin, where orographic effects caused strong surface winds. According to short-range numerical simulations, dust particles were confined to near-ground layers around the emission areas. On the other hand, dust aerosols were injected up to 5–6 km high in central and southern regions of the Fiambalá Basin, where intense ascending airflows are driven by horizontal convergence. Long-range transport numerical simulations were also performed to model dust cloud spreading over northern Argentina. Results of simulated vertical particle column mass were compared with the MSG-SEVIRI retrieval product. We tested two numerical schemes: with the default configuration of the FALL3D model, we found difficulties to simulate transport through orographic barriers, whereas an alternative configuration, using a numerical scheme to more accurately compute the horizontal advection in abrupt terrains, substantially improved the model performance.

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