scholarly journals Origin and Route of Severe Dust Storms in West Asia (with Horizontal Visibility Less Than 1000 Meters)

2021 ◽  
Author(s):  
zainab Mohammadi ◽  
hassan lashkari
Keyword(s):  
Large Scale ◽  
Temporal Distribution ◽  
Middle Layer ◽  
Dust Storms ◽  
The West ◽  
Horizontal Visibility ◽  
Northwestern Saudi Arabia ◽  
The North ◽  
South Of Iraq ◽  
Annual Distribution

Abstract Storms are intensified atmospheric phenomena which are sometimes accompanied by heavy rainfall and sometimes by dust. Dust storms, especially storms with horizontal visibility of fewer than 1000 meters, have always been harmful and detrimental to human comfort and health. In recent decades, the worrisome phenomena of conflict, climate change, and droughts have increased the frequency of dust storms in West Asia. Identifying the source and route of dust storms is the first step in limiting the harm they inflict. To investigate this phenomenon, using the daily data of the Meteorological Organization of Iran, storms with horizontal visibility of less than 1000 meters in the southwestern region of Iran, as one of the destination areas of these storms, in a statistical period of 33 years (1987 to 2019) was extracted. First, the monthly, seasonal and annual distribution of dust storms in 13 synoptic stations in this area was investigated. Then, using the site https://www.ready.noaa.gov/HYSPLIT by backward method from the GDAS data system with a step of 0.5 degrees, the origin and path of the storms were identified. Finally, maps of each route were drawn in ArcGIS 10.6. The findings of this study revealed that the biggest number of dust storms occurred in the winter, in terms of temporal distribution (38% of storms). With 23% of storms, spring is in second position. In terms of monthly distribution, the month of January has the most storms, followed by February and December. Storms decrease in intensity as they move from the south to the north, and from the west to the east of the region. The central region of Iraq ranks first in terms of storm origin, accounting for 25% of all storms. If dust storms originating in western Iraq are added to this number, about 35% of storms in west Asia originate in western and central Iraq. Regarding the pattern of large-scale atmospheric circulation prevailing in the middle layer of the atmosphere in this region, most of these dust storms in the west-east direction, after passing through the center and south of Iraq, enter Iran. The study also shows that storms in Syria، Jordan or northwestern Saudi Arabia, are very thick. These storms cover the middle layer of the troposphere and then affect high stations such as Shahrekord and Yasuj with an altitude of more than 2000 meters.

Analisys of mud inrush water sources into underground working of the Sokolovskoe ore deposit

2020 ◽  
pp. 56-67
Author(s):  
E. Yu. Efremov
Keyword(s):  
Hydraulic Conductivity ◽  
Large Scale ◽  
Underground Mining ◽  
Temporal Distribution ◽  
High Water ◽  
The North ◽  
Initial Block ◽  
Groundwater Supply ◽  
Spatio Temporal ◽  
Inrush Water

There is a serious threat of groundwater inrush from overlying sedimentary layers for underground mining. When ore is extracted using block caving method, the area of overburden collapse over ore zone disrupts the natural structure of high hydraulic-conductivity and low hydraulic-conductivity layers. This process creates conditions for the accumulation and transfer of groundwater to mine workings, which lead to accidents, up to disastrous proportions. The research aim is to determine the spatio-temporal distribution of mud inrushes, and to identify groundwater supply sources of inrushes to reduce the geotechnical risks of underground mining in Sokolovskaya mine. Research methods include localization, classification, and analysis of monitoring data, comparison of mud inrushes distribution with geostatistical parameters of the main aquifers.The majority of large-scale accidents caused by mud inrushes are confined to the central and northern area of caved rock zone. The most risky stage of the ore body extraction is the initial block at the lower extraction level. The sources of water supply for the majority of the mud inrushes are high water level areas of the Cretaceous aquifer to the north and west of the mine. Rational targeted drainage aimed at draining the identified areas of the aquifer is the best way to reduce the risk of accidents.

scholarly journals Mathematical Modeling of Vortex Interaction Using a Three-Layer Quasigeostrophic Model. Part 2: Finite-Core-Vortex Approach and Oceanographic Application

Mathematics ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 1267
Author(s):  
Mikhail A. Sokolovskiy ◽  
Xavier J. Carton ◽  
Boris N. Filyushkin
Keyword(s):  
Large Scale ◽  
Lower Layer ◽  
Middle Layer ◽  
Vortex Interaction ◽  
Vortex Dipoles ◽  
The North ◽  
Surface Cyclone ◽  
Vertical Density ◽  
Quasigeostrophic Model ◽  
The Stability

The three-layer version of the contour dynamics/surgery method is used to study the interaction mechanisms of a large-scale surface vortex with a smaller vortex/vortices of the middle layer (prototypes of intrathermocline vortices in the ocean) belonging to the middle layer of a three-layer rotating fluid. The lower layer is assumed to be dynamically passive. The piecewise constant vertical density distribution approximates the average long-term profile for the North Atlantic, where intrathermocline eddies are observed most often at depths of 300–1600 m. Numerical experiments were carried out with different initial configurations of vortices, to evaluate several effects. Firstly, the stability of the vortex compound was evaluated. Most often, it remains compact, but when unstable, it can break as vertically coupled vortex dipoles (called hetons). Secondly, we studied the interaction between a vertically tilted cyclone and lenses. Then, the lenses first undergo anticlockwise rotation determined by the surface cyclone. The lenses can induce alignment or coupling with cyclonic vorticity above them. Only very weak lenses are destroyed by the shear stress exerted by the surface cyclone. Thirdly, under the influence of lens dipoles, the surface cyclone can be torn apart. In particular, the shedding of rapidly moving vortex pairs at the surface reflects the presence of lens dipoles below. More slowly moving small eddies can also be torn away from the main surface cyclone. In this case, they do not appear to be coupled with middle layer vortices. They are the result of large shear-induced deformation. Common and differing features of the vortex interaction, modeled in the framework of the theory of point and finite-core vortices, are noted.

Structural and metamorphic relationships between the Mount Ida and Monashee Groups at Mara Lake, British Columbia

1982 ◽  
Vol 19 (2) ◽  
pp. 288-307 ◽  
Author(s):  
Kent C. Nielsen
Keyword(s):  
British Columbia ◽  
Large Scale ◽  
Ductile Deformation ◽  
Late Triassic ◽  
Second Phase ◽  
The West ◽  
Late Mesozoic ◽  
The North ◽  
Phase Deformation ◽  
Metamorphic Core

Mara Lake, British Columbia straddles the boundary between the Monashee Group on the east and the Mount Ida Group on the west. Correlation of units across the southern end of Mara Lake indicates lithologic continuity between parts of the groups. Both groups have experienced four phases of deformation. Phases one and two are tight and recumbent, trending to the north and to the west, respectively. Phases three and four are open to closed and upright, trending northwest and northeast, respectively. Second-phase deformation includes large-scale tectonic slides that separate areas of consistent vergence. Slide surfaces are folded by third- and fourth-phase structures and outline domal outcrop patterns. Metamorphic grade increases from north to south along the west side of Mara Lake. Calc-silicate reactions involving the formation of diopside are characteristic. From west to east increasing grade is evident in the reaction of muscovite + quartz producing sillimanite + K-feldspar + water. These prograde reactions are related to relative position in the second-phase structure. The highest grade is located near the lowest slide surface. Greenschist conditions accompanied phase-three deformation. Fourth phase is characterized by hydrothermal alteration, brittle fracturing, and local faulting. First-phase deformation appears to be pre-Late Triassic whereas second and third phases are post-Late Triassic and pre-Cretaceous. The fourth phase is part of a regional Tertiary event. The third folding event is correlated with the development of the Chase antiform and the second-phase folding is related to the pervasive east–west fabric of the Shuswap Complex. The timing of these events indicates that the metamorphic core zone of the eastern Cordillera was relatively rigid during the late Mesozoic foreland thrust development. Ductile deformation significantly preceded thrusting and developed a fabric almost at right angles to the trend of the thrust belt.

scholarly journals The Tell-Rif orogenic system (Morocco, Algeria, Tunisia) and the structural heritage of the southern Tethys margin

2018 ◽  
Vol 189 (2) ◽  
pp. 10 ◽  
Author(s):  
Rémi Leprêtre ◽  
Dominique Frizon de Lamotte ◽  
Violaine Combier ◽  
Oriol Gimeno-Vives ◽  
Geoffroy Mohn ◽  
...  
Keyword(s):  
Large Scale ◽  
Lateral Spreading ◽  
Direct Result ◽  
Deep Basin ◽  
The West ◽  
The North ◽  
Slab Tearing ◽  
Geodynamic Models ◽  
Back Arc ◽  
Central Atlantic

The Tell-Rif (Tell in Algeria and Tunisia; Rif in Morocco) is the orogenic system fringing to the south the West Mediterranean basins. This system comprises three major tectonic-palaeogeographic zones from north to south: (1) the internal zones (AlKaPeCa for Alboran, Kabylies, Peloritan, Calabria) originating from the former northern European margin of the Maghrebian Tethys, (2) the “Flyschs zone” regarded as the former cover of the oceanic domain and (3) the external zones, forming the former southern Maghrebian Tethys margin more or less inverted. The Tell-Rif is interpreted as the direct result of the progressive closure of the Maghrebian Tethys until the collision between AlKaPeCa and Africa and, subsequently, the propagation of the deformation within Africa. This gives a consistent explanation for the offshore Neogene geodynamics and most authors share this simple scenario. Nevertheless, the current geodynamic models do not completely integrate the Tell-Rif geology. Based on the analysis of surface and sub-surface data, we propose a reappraisal of its present-day geometry in terms of geodynamic evolution. We highlight its non-cylindrical nature resulting from both the Mesozoic inheritance and the conditions of the tectonic inversion. During the Early Jurassic, we emphasize the development of NE-SW basins preceding the establishment of an E-W transform corridor connecting the Central Atlantic Ocean with the Ligurian Tethys. The Maghrebian Tethys developed just after, as the result of the Late Jurassic-Early Cretaceous left-lateral spreading between Africa and Iberia. By the Late Cretaceous, the occurrence of several tectonic events is related to the progressive convergence convergence between the two continents. A major pre-Oligocene (pre-35 Ma) compressional event is recorded in the Tell-Rif system. The existence of HP-LT metamorphic rocks associated with fragments of mantle in the External Metamorphic Massifs of the Eastern Rif and Western Tell shows that, at that time, the western part of the North-African margin was involved in a subduction below a deep basin belonging to the Maghrebian Tethys. At the same time, the closure of the West Ligurian Tethys through east-verging subduction led to a shift of the subduction, which jumped to the other side of AlKaPeCa involving both East Ligurian and Maghrebian Tethys. Slab rollback led to the development of the Oligo-Miocene back-arc basins of the West-Mediterranean, reworking the previous West Ligurian Tethys suture. The docking of AlKaPeCa against Africa occurred during the Late Burdigalian (17 Ma). Subsequently, the slab tearing triggered westward and eastward lateral movements that are responsible for the formation of the Gibraltar and Tyrrhenian Arcs respectively. The exhumation of the External Metamorphic Massifs occurred through tectonic underplating during the westward translation of the Alboran Domain. It resulted in the formation of both foredeep and wedge-top basins younger and younger westward. The lack of these elements in the eastern part of the systems signs a different evolution dominated by frontal accretion. In the discussion, we precisely address the origin of the non-cylindrical behavior of the orogenic system and question the mechanisms explaining at large scale the phases of coupling/uncoupling between the major plates.

The Dabona Cemetery in Xiangyun County, Yunnan

2016 ◽  
Vol 16 (1) ◽  
pp. 13-26
Keyword(s):  
Large Scale ◽  
Erhai Lake ◽  
Warring States Period ◽  
Social Situations ◽  
The West ◽  
Warring States ◽  
The North ◽  
Lake Region ◽  
The People ◽  
The Social

Abstract In 2014, Yunnan Provincial Institute of Cultural Relics and Archaeology and other institutions conducted large-scale excavation to the Dabona Cemetery located in Dabona Village and to its east of the Liuchang Town, Xiangyun County. The west zone of the Dabona Cemetery had widely distributed early cultural remains, including house foundations, postholes, ash pits, ash ditches, etc. The east zone consisted of two sections distributed in the north-south direction, in the north section of which 25 burials were recovered; among these burials, six were large-sized ones with lengths more than 6m, and the other were medium- and small-sized burials. The grave goods unearthed from these burials reflected that the dates of the remains and burials were roughly in the Warring-States Period to the Qin and Han Dynasties. The area where these remains and burials were located was the main inhabited area of the people of Kunming ethnic group; this excavation provided important materials for the researches on the features and the social situations of the bronze cultures in the Erhai Lake region.

Building Domestic Support for West Germany's Integration into NATO, 1953–1955

2020 ◽  
Vol 22 (2) ◽  
pp. 133-162
Author(s):  
Jan Uelzmann
Keyword(s):  
Public Relations ◽  
Large Scale ◽  
Federal Republic Of Germany ◽  
Lower Saxony ◽  
The West ◽  
The North ◽  
Public Sentiment ◽  
Competing Events ◽  
The Government ◽  
Domestic Support

Konrad Adenauer's government in the Federal Republic of Germany (FRG) engaged in a large-scale media campaign to create political consent for the FRG's integration into the West, a policy that rested to a large extent on rearmament and entry into the North Atlantic Treaty Organization. To counter public criticism of rearmament, the West German authorities used Mobilwerbung, a company that maintained a fleet of mobile film screening vans. Clandestinely financed by the government, Mobilwerbung brought government-commissioned films and political speakers into the FRG's remotest areas. Based on archival records on deployments in Lower Saxony and North Rhine-Westphalia, this article traces Mobilwerbung's role as a government unit that reacted dynamically to competing events. Through highly detailed reporting on audience reactions, Mobilwerbung served both as a public relations vehicle to foster consent and as an analytical tool that allowed the mapping of public sentiment regarding rearmament.

scholarly journals A Preliminary Study: Marine Biogeography of Nautilus in the Bangka Belitung Seas, Indonesia

2021 ◽  
Vol 26 (3) ◽  
pp. 147-154
Author(s):  
Siti Aisyah ◽  
Josaphat Tetuko Sri Sumantyo ◽  
Aditya Pamungkas ◽  
M Rizza Muftiadi ◽  
Muh Yusuf
Keyword(s):  
Large Scale ◽  
Local Area ◽  
Limiting Factor ◽  
The West ◽  
Living Fossil ◽  
The North ◽  
Surface Temperatures ◽  
Special Cases ◽  
Original Habitat ◽  
West Monsoon

Nautilus is the only surviving genus whose members were numerous and widely dispersed in the oceans throughout the Jurassic and Miocene times. It represents the only living member from the Family Nautilidae and is often considered as a living fossil. Nautilus is found with high biodiversity in Ambon, Indonesia, and were in special cases even found in Bangka Belitung, far from their original habitat. This study aimed to understand the historical component of the habitat and distribution of Nautilus in Bangka Belitung and to determine the depth, temperature, current, and environmental heterogeneity relate to Nautilus. Nautilus samples were found in Bangka Belitung Seas nearby a crack region at 50–75 m deep while the optimal depth of the Nautilus was 150–300 m, depending on the local area. The locations in the Bangka Belitung Seas where Nautilus found have sea surface temperatures between 30-31°C and 27-28°C during the East Monsoon and the West Monsoon respectivelly. The implications of temperature as a limiting factor are fairly significant, as it restricts the upper limit of the living habitat to predictable depths, which vary both geographically and seasonally during the West Monsoon when surface temperatures approach habitable levels. Sea currents at the Bangka Belitung Seas move at 0–0.6 m.s-1 during the East Monsoon and speed up near the North Natuna Sea. During the West Monsoon, currents predominantly flow from the Natuna Sea to the Java Sea at 0–0.5 m.s-1. Large-scale deep-water currents and the effects of smaller currents on scent dispersal influence the directional movements of Nautilus.

scholarly journals A regional real-time forecast of marine boundary layers during VOCALS-Rex

2010 ◽  
Vol 10 (8) ◽  
pp. 18419-18466 ◽  
Author(s):  
S. Wang ◽  
L. W. O'Neill ◽  
Q. Jiang ◽  
S. P. de Szoeke ◽  
X. Hong ◽  
...  
Keyword(s):  
Real Time ◽  
Large Scale ◽  
Marine Boundary Layer ◽  
Surface Wind ◽  
Lower Troposphere ◽  
Temporal Distribution ◽  
Satellite Observations ◽  
Naval Research ◽  
Strong Wind ◽  
The West

Abstract. This paper presents an evaluation and validation of the Naval Research Laboratory's COAMPS real-time forecasts during the VOCALS-Rex over the area off the west coast of Chile/Peru in the Southeast Pacific during October and November 2008. The analyses focus on the marine boundary layer (MBL) structure. These forecasts are compared with lower troposphere soundings, surface measurements, and satellite observations. The predicted mean MBL cloud and surface wind spatial distributions are in good agreement with the satellite observations. The large-scale longitudinal variation of the MBL structure along 20° S is captured by the forecasts. That is, the MBL heights increase toward the open ocean, the moisture just above the inversion decreases, and the MBL structure becomes more decoupled offshore. The observed strong wind shear across the cloud-top inversion in coastal area at 20° S was correctly predicted by the model. Our results show that the sporadic cloud spatial and temporal distribution in the 15 km grid mesh is caused by grid-scale convection likely due to a lack of a shallow cumulus convection parameterization in the model. Both observations and model forecasts show wind speed maxima near the top of MBL along 20° S, which is consistent with the west-ward upslope of the MBL heights based on the thermal wind relationship. The forecasts produced well-defined diurnal variations in the spatially averaged MBL structure, although the overall signal is weaker than those derived from the in situ measurements and satellite data. The MBL heights are generally underpredicted in the nearshore area. The analysis of the sensitivity simulations with regard to grid resolution suggests that the under-prediction is likely associated with over-prediction of the mesoscale downward motion and cold advection along the coast.

scholarly journals Sensitivity of free tropospheric carbon monoxide to atmospheric weather states and their persistency: an observational assessment over the Nordic countries

2014 ◽  
Vol 14 (21) ◽  
pp. 11545-11555 ◽  
Author(s):  
M. A. Thomas ◽  
A. Devasthale
Keyword(s):  
Carbon Monoxide ◽  
Long Range ◽  
Large Scale ◽  
Temporal Distribution ◽  
Sensitivity Study ◽  
Nordic Countries ◽  
Long Range Transport ◽  
Observational Assessment ◽  
The North ◽  
Range Transport

Abstract. Among various factors that influence the long-range transport of pollutants in the free troposphere (FT), the prevailing atmospheric weather states probably play the most important role in governing characteristics and efficacy of such transport. The weather states, such as a particular wind pattern, cyclonic or anticyclonic conditions, and their degree of persistency determine the spatio-temporal distribution and the final fate of the pollutants. This is especially true in the case of Nordic countries, where baroclinic disturbances and associated weather fronts primarily regulate local meteorology, in contrast to the lower latitudes where a convective paradigm plays a similarly important role. Furthermore, the long-range transport of pollutants in the FT has significant contribution to the total column burden over the Nordic countries. However, there is insufficient knowledge on the large-scale co-variability of pollutants in the FT and atmospheric weather states based solely on observational data over this region. The present study attempts to quantify and understand this statistical co-variability while providing relevant meteorological background. To that end, we select eight weather states that predominantly occur over the Nordic countries and three periods of their persistency (3 days, 5 days, and 7 days), thus providing in total 24 cases to investigate sensitivity of free tropospheric carbon monoxide, an ideal tracer for studying pollutant transport, to these selected weather states. The eight states include four dominant wind directions (namely, NW, NE, SE and SW), cyclonic and anticyclonic conditions, and the enhanced positive and negative phases of the North Atlantic Oscillation (NAO). For our sensitivity analysis, we use recently released Version 6 retrievals of CO at 500 hPa from the Atmospheric Infrared Sounder (AIRS) onboard Aqua satellite covering the 11-year period from September 2002 through August 2013 and winds from the ECMWF's ERA-Interim project to classify weather states for the same 11-year period. We show that, among the various weather states studied here, southeasterly winds lead to highest observed CO anomalies (up to +8%) over the Nordic countries while transporting pollution from the central and eastern parts of Europe. The second (up to +4%) and third highest (up to +2.5%) CO anomalies are observed when winds are northwesterly (facilitating inter-continental transport from polluted North American regions) and during the enhanced positive phase of the NAO respectively. Higher than normal CO anomalies are observed during anticyclonic conditions (up to +1%) compared to cyclonic conditions. The cleanest conditions are observed when winds are northeasterly and during the enhanced negative phases of the NAO, when relatively clean Arctic air masses are transported over the Nordic regions in the both cases. In the case of nearly all weather states, the CO anomalies consistently continue to increase or decrease as the degree of persistency of a weather state is increased. The results of this sensitivity study further provide an observational basis for the process-oriented evaluation of chemistry transport models, especially with regard to the representation of large-scale coupling of chemistry and local weather states and its role in the long-range transport of pollutants in such models.

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