Eolian dust

The environmental impacts as well as the economical aspects and regulation constraints related to wind erosion motivate current efforts to model and quantify erosion. The nature of the underlying processes makes quantification of diffuse dust emissions a very demanding exercise that is still subject of active research. Certain aspects were not fully apprehended, others require further development. These include the influence of the wide size distribution of granular materials and the sensitivity of the stockpiles' wind exposure on industrial sites to various parameters, such as the geometry of the pile and its location as well as the wind conditions. The objective of this work is to improve the accuracy of diffuse dust emissions' estimations, by creating precise and detailed databases for existing models. Three-dimensional numerical simulations were developed and validated in order to investigate the sensitivity of the mean flow structure to varying stockpile geometries and wind conditions. A second local approach was also applied, which aims to study flow characteristics and the evolution of the friction velocity at the wall in the presence of nonerodible elements for various configurations and roughness densities. The numerical data can be used in order to improve the current models' accuracy and performance.

Dust storms are one of the main environmental challenges, particularly in West Asian Region. The phenomenon has great harmful impacts on the countries of the region including Iran, Iraq, Syria, Kuwait, and other countries around Persian Gulf. Intensification of the phenomenon in recent years made it necessary to find a suitable solution to combat against the devastating events. Therefore, the headquarter of water resources development, drought, erosion and environment assigned a project entitled “Investigation of Dust Storms in West Asian Region” to Geoinformatic Research Institute (GRI) of the University of Tehran in order to study the regional phenomenon. United Nations Environmental Program (UNEP) Regional Office of West Asia (ROWA) also supported this project because of its regional nature and the need for participation from national, regional and international organizations.
The output and outcomes of this project entitled “Investigation of Dust Storms in West Asian Region” is three reports:
 Primary Investigation of Dust Storm Sources in West Asia (With an Emphasis on Storms Came to Iran)
 Analysis of Fundamentals, Identification Criteria, and Modeling of Dust Storms (With emphasis on West Asia Region)
 Investigation of factors of dust storms and solutions for combating (With emphasis on West Asia Region)
Members of the team are greatly thankful to kind cooperation of all professors, students, colleagues, and the experts who assisted in conduction of this project. The team is also especially grateful to vice-president for science and technology affairs of Islamic republic of Iran and UNEP-ROWA. All kinds of criticism and suggestions are warmly welcomed by the team members.
Dr. Hossein Ali Bahrami
Secretariat of the headquarter of water resources development, drought, erosion and environment technologies (vice-president for science and technology affairs of Islamic republic of Iran)
Dr. Ali Darvishi Bolourani
The head of International Geoinformatic Reseach Institute of the University of Tehran (GRI) and the executer of the project
Dr. Abdol Majid Hadad
Environemntal Program of United Nations, Regional Office of West Asia (UNEP-ROWA)

The viscosity of pantelleritic melts from the Khaggiar lava flow (5.5 ka -Pantelleria Island) was investigated as a function of temperature and water content. High (1673-1323 K) and low (973-613 K) temperature dry and hydrous liquid viscosities were determined by a combination of concentric cylinder (10 2.44 to 10 4.56 Pa s) and micropenetration (10 8.67 to 10 11.37 ) viscometric techniques. The effect of water, from 0.02 to 3.55 wt.% H 2 O, was explored in the temperature range of 973-613 K. Liquid viscosities have been parameterized by means of a modified Vogel-Fulcher-Tammann equation (VFT) which describes viscosities and derivative properties (glass transition temperature T g , fragility m) of silicic liquids as a function of T-X (H 2 O). The results yield the expected strong decrease of viscosity with temperature and water content. Fragility, as a measure of the deviation from Arrhenian behavior, increases with H 2 O content from m =23 to m = 28. The peralkalinity (molar alkali excess over alumina), which characterizes the pantelleritic magmas, exerts a primary control over the rheological behavior of these melts. The excess of alkalies over alumina content is responsible for the peculiarly low viscosities of pantelleritic liquids compared to their metaluminous counterpart in the high temperature range, and leads to an even more dramatic decrease in the viscosities of these rhyolites in the low temperature range. Comparison with available models shows substantial differences between the measured and calculated viscosities. Based on our new viscosity results combined with existing literature data, we propose a new parameterization based on a modified Vogel-Fulcher-Tammann equation, accounting for the effect of water and composition, which can be used to determine the viscosity of pantelleritic melts. The derived relationship reproduces the experimental data (58 in total) in the viscosity range from 10 2.44 to 10 11.37 Pa s and in the temperature range from 613 to 1673 K within a root-mean-square-error (RMSE) of 0.12 log units. Application of this calculation model for high temperature low viscosity hydrous melt is limited by the lack of experimental data and needs verification by additional measurements. Volcanological implications for welding and rheomorphic processes as well as conduit dynamic modeling are also discussed in light of the results presented in this work.

This contribution describes the development, calibration and verification of a 1-D behaviour-orientated shoreline prediction model. The model primarily encapsulates shoreline displacement forced by wave-driven cross-shore sediment transport. Hysteresis effects are shown to be important and are included in the model, whereby present shoreline change is influenced by past hydro-/morpho-dynamic conditions. The potential magnitude of shoreline change increases with incident wave power and the degree of disequilibrium. The latter disequilibrium term (Ω eq − Ω) is expressed in terms of the time-evolving equilibrium (Ω eq ) and instantaneous (Ω) dimensionless fall velocities and dictates the direction of shoreline movement. Following the equilibrium fall velocity is defined as a function of the weighted antecedent conditions and is a proxy for the evolving beach state. The decay rate of the weighting function used to compute Ω eq is a model free parameter determined by calibration against measured data, which physically reflects the degree of observed 'memory' of the system. The decay in amplitude of this weighting function with time is controlled by a 'memory decay' term (ϕ), where the weighting reaches 10%, 1% and 0.1% at ϕ, 2ϕ and 3ϕ days prior to the current calculation time. The model is applied to two multi-year (6+ years) data sets incorporating hourly wave and weekly shoreline measurements, from two contrasting energetic sites in SE Australia. The first is the relatively dissipative, straight Gold Coast (QLD) and the second is a more intermediate embayed beach at Narrabeen (NSW). The model shows significant skill at hindcasting shoreline change at both sites, predicting approximately 60% of the total shoreline variability. The Gold Coast shoreline is dominated by a strong seasonal signal. Conversely, at the Narrabeen embayment, shoreline variability (and morphology) is more dynamic, responding at storm frequency. Evidence suggests that there is a strong coherence between the shoreline position and morphodynamic state and that both have response times characterised by ϕ. It is hypothesised that optimised ϕ values in the shoreline model physically relate to the efficiency of sediment exchanges between the shoreface and offshore bars and the prevalence of one-or two-dimensional horizontal circulation. The general success of this new shoreline model for hindcasting the observed shoreline behaviour at two distinctly different open-coast sites suggests that this approach may be suitable for broader application.

In combination with the desiccation of the Aral Sea and the formation of the Aral Kum, the dry sea bed became a new source for dust and sand storms. Due to the highly continental climate and the effects of the global climate change in the region, increasing air pressure differences lead to an increasing frequency of high intensity wind events. The resulting aeolian dust movements can be tracked and split into short and long distance transfers using remote sensing approaches, but hard data about the spatial and temporal distribution of the dust deposition requires excessive ground research and thus is scarce. Therefore, we have analyzed the passive dust deposition data from 23 meteorological stations and assessed the spatial and temporal transfer patterns within several transects from the banks of the former Aral Sea in eastern and southern directions covering parts of Kazakhstan, Uzbekistan and Turkmenistan. Dust was collected on a monthly base as well as during specific dust storm events between 2003 and 2012 in the framework of three research projects for both long-term and event based deposition data. Dust transfer in southern direction was the most important trajectory and the newly formed Aral Kum proved to be an important source region for aeolian dust (besides the natural deserts Kyzyl Kum and Kara Kum). Stations close to these source regions frequently showed deposition rates exceeding international thresholds, resulting in possible negative effects on human and livestock health while the mineralogical and chemical composition of the deposited material influences the arable land in this arid region. This presentation will summarize the most important findings from the three research projects and discuss measures to reduce the wind erosion in the Aral Kum.

Loess deposits are recorders of aeolian activity during past glaciations. Since the size
distribution of loess deposits depends on distance to the dust source, and environmental
conditions at the source, during transport, and at deposition, loess particle size distributions
and derived statistical measures are widely used proxies in Quaternary paleoenvironmental
studies. However, the interpretation of these proxies often only consider dust transport
processes. To move beyond such overly simplistic proxy interpretations, and toward proxy
interpretations that consider the range of environmental processes that determine loess particle
size distribution variations we provide a comprehensive review on the physics of dust particle
mobilization and deposition. Furthermore, using high-resolution bulk loess and quartz grain
size datasets from a last glacial/interglacial sequence, we show that, because grain size
distributions are affected by multiple, often stochastic processes, changes in these
distributions over time allow multiple interpretations for the driving processes. Consequently,
simplistic interpretations of proxy variations in terms of only one factor (e.g. wind speed) are
likely to be inaccurate. Nonetheless using loess proxies to understand temporal changes in the
dust cycle and environmental parameters requires (i) a careful site selection, to minimize the
effects of topography and source distance, and (ii) the joint use of bulk and quartz grain size
proxies, together with high resolution mass accumulation rate calculations if possible.

Dust storms tend to form in sparsely populated areas covered by only few observations. Dust source maps, known as source functions, are used in dust models to allocate a certain potential of dust release to each place. Recent research showed that the well known Ginoux source function (GSF), currently used in Weather Research and Forecasting Model coupled with Chemistry (WRF-chem), exhibits large errors over some regions in West Asia, particularly near the IRAQ/Syrian border. This study aims to improve the specification of this critical part of dust forecasts. A new source function based on multi-year analysis of satellite observations, called West Asia source function (WASF), is therefore proposed to raise the quality of WRF-chem predictions in the region. WASF has been implemented in three dust schemes of WRF-chem. Remotely sensed and ground-based observations have been used to verify the horizontal and vertical extent and location of simulated dust clouds. Results indicate that WRF-chem performance is significantly improved in many areas after the implementation of WASF. The modified runs (long term simulations over the summers 2008–2012, using nudging) have yielded an average increase of Spearman correlation between observed and forecast aerosol optical thickness by 12–16 percent points compared to control runs with standard source functions. They even outperform MACC and DREAM dust simulations over many dust source regions. However, the quality of the forecasts decreased with distance from sources, probably due to deficiencies in the transport and deposition characteristics of the forecast model in these areas.

Loess is common in the Mid-Atlantic region of the United States south of the Late Wisconsinan glacial border particularly along rivers draining the glaciated areas of Pennsylvania, New Jersey, and New York. The broadest deposits occur on the flat landscapes of the Delmarva Peninsula in Maryland where two episodes of deposition have been identified. The earlier Miles Point Loess has a limited distribution and is buried by the more widespread Paw Paw Loess. OSL and 14C dates place deposition of the Miles Point Loess during MIS 3. The well developed paleosol formed in the Miles Point Loess acts as a stratigraphic marker. The Paw Paw Loess buries Clovis age cultural materials which date deposition to the end of the Pleistocene. Loess deposits and paleosols are critical in understanding regional landscape evolution, Late Pleistocene environments, and early North American cultural history. Mapping the extent of loess in the Mid-Atlantic using the Natural Resources Conservation Service's gSSURGO database overrepresents loess in some areas and underrepresents in others.

The transport of sand and dust by wind is a potent erosional force, creates sand dunes and ripples, and loads the atmosphere with suspended dust aerosols. This article presents an extensive review of the physics of wind-blown sand and dust on Earth and Mars. Specifically, we review the physics of aeolian saltation, the formation and development of sand dunes and ripples, the physics of dust aerosol emission, the weather phenomena that trigger dust storms, and the lifting of dust by dust devils and other smallscale vortices. We also discuss the physics of wind-blown sand and dune formation on Venus and Titan.

This paper presents the results on the influence of cement kiln dust on index and compaction characteristics on lateritic soils and black cotton soils. Laboratory test were carried out on the lateritic soil and Black cotton soil used was found out to be A 41.5% passing the BS No. 200 sieve, is of High plasticity of 22.3% and Medium swelling potential of 2.40%. The Black cotton soil is swelling potential of 9.35%. This renders it an unsuitable material for most geotechnical purpose. Soils with a high PI tend to be clay; indicate that the addition of Cement kiln dust reduced the plasticity of lateritic soil and thereby improved its workability and reduced its moisture holding capacity and swell potential. The best sample on La found to be Lateritic soil with 9% CKD which has 14.6% Plasticity Index which has soil class of A soil, Black cotton soil with 12% CKD was found to be the Optimum value, 17.0% Plasticity Index (PI) of soil class A Dry density reflects the soil's ability to function for structural support, water and solute movement, and soil aeration. High density is an indicator of low soil porosity and soil compaction. Moisture content in soil affects its bearing capacity. When the s Therefore, the higher the moisture content the lower its ability to loads subjected to a soil. the optimum and Maximum dry densit CKD. Addition of CKD at 12% will increase the compaction characteristics of Black cotton soil. At 9% Lateritic soil shows the optimum dry density value of 1.70g/m CKD.

ABSTRACT  This study identifies anthropogenically disturbed areas and barren playa surfaces as the two primary dust source types that repeatedly contribute to dust storm events in the eastern Great Basin of western Utah, U.S.A. This semi-arid desert region is an important contributor to dust production in North America, with this study being the first to specifically identify and characterize regional dust sources. From 2004 to 2010, a total of 51 dust event days (DEDs) affected the air quality in Salt Lake City, UT. MODIS satellite imagery during 16 of these DEDs was analyzed to identify dust plumes, and assess the characteristics of dust source areas. A total of 168 plumes were identified, and showed mobilization of dust from Quaternary deposits located within the Bonneville Basin. This analysis identifies 4 major and 5 secondary source areas for dust in this region, which pro- duce dust primarily during the spring and fall months and during moderate or greater drought conditions, with a Palmer Drought Index (PDI) of −2 or less. The largest number of observed dust plumes (~60% of all plumes) originated from playas (ephemeral lakes) and are classified as barren land cover with a silty clay soil sediment surface. Playa surfaces in this region undergo numerous recurrent anthropogenic disturbances, including mili- tary operations and anthropogenic water withdrawal. Anthropogenic disturbance is necessary to produce dust from the vegetated landscape in the eastern Great Basin, as evidenced by the new dust source active from 2008 to 2010 in the area burned by the 2007 Milford Flat Fire; this fire was the largest in Utah's history due to extensive cover of invasive cheatgrass (Bromus tectorum) along with drought conditions. However, dust mobili- zation from the Milford Flat Burned Area was limited to regions that had been significantly disturbed by post-fire land management techniques that consisted of seeding, followed by chaining or tilling of the soil. Dust storms in the eastern Great Basin negatively impact air quality and transportation in the populated regions of Utah; this study details an improved forecasting protocol for dust storm events that will benefit transportation planning and improve public health.

Com vista a estudar a deposição sobre a ilha Terceira -Açores, no período de 1 de Março a 16 de Março de 2009, de poeiras oriundas do Saara, recorreu-se a imagens da sonda TOMS-Nimbus (Total Ozone Mapping Spectrometer), que avalia as propriedades ópticas das poeiras em suspensão na atmosfera, e a partir dessas imagens diárias, construi-se uma animação com as mesmas, de modo a verificar a intensidade e duração do evento.

Interactions of desert dust and air pollution over the eastern Mediterranean (EM) have been studied, focusing on two distinct dust transport events on 22 and 28 Septem-ber 2011. The atmospheric chemistry–climate model EMAC has been used at about 50 km grid spacing, applying an on-line dust emission scheme and calcium as a proxy for dust reactivity. EMAC includes a detailed tropospheric chemistry mechanism, aerosol microphysics and thermodynam-ics schemes to describe dust " aging ". The model is evaluated using ground-based observations for aerosol concentrations and aerosol optical depth (AOD) as well as satellite observations. Simulation results and back trajectory analysis show that the development of synoptic disturbances over the EM can enhance dust transport from the Sahara and Ara-bian deserts in frontal systems that also carry air pollution to the EM. The frontal systems are associated with precipitation that controls the dust removal. Our results show the importance of chemical aging of dust, which increases particle size, dust deposition and scavenging efficiency during transport, overall reducing the lifetime relative to non-aged dust particles. The relatively long travel periods of Saharan dust result in more sustained aging compared to Arabian dust. Sensitivity simulations indicate 3 times more dust deposition of aged relative to pristine dust, which significantly decreases the dust lifetime and loading.

Sedimentation is a major process for removal of particulate material from the water column and important determinant accounting for the stability of aquatic ecosystems. Gross sedimentation rates (GSR) in Lake Kinneret (Israel), regularly monitored from 1999 up-to-date with sedimentation traps, showed salient temporal and spatial variability. In the lake center, the annual mean GSR ranged from 1.9 to 6.0 g m-2 d-1. The accumulation rate of sediments at the lake centrum during the study averaged from 2.6 to 4.3 mm yr-1, in agreement with values obtained by sediment core dating. Organic matter (OM) content comprised 33-42% of the sinking particulate mater in sediment traps located in the lake centre and was 1.5-2 times lesser in peripheral stations. The highest seasonal values of OM content in traps were associated with collapse of algal blooms. Algae and their debris are the main component of OM and their fate in the water column can be well traced by photosynthetic pigments. Chlorophyte signature pigments display much lower degradability in the water column than those of diatoms and dinoflagellates and leave a relatively persistent residue in the buried sediments. Despite large variation in algal community composition, the ratio of OM sedimentation flux to primary production (i.e., the export ratio) alters only slightly throughout the stratified period. Approximately 20% of the OM supplied to the lake by primary production founds its way to the traps. A large decline of water level in recent years affected the processes of particle resuspension and offshore translocation, which caused prominent site-specific impacts on the sedimentation regime. We argue that changes in sedimentation rates observed in the lake are related to fluctuations of loads from the watershed and prominent water level fluctuations.

Reports of microbes collected at different layers of the atmosphere from previously existing studies were collated, compared, and summarized. An attempt was made to quantify the role of and identify the nature microbial life that exists in Earth’s atmosphere, provide information on mechanisms and transport, and establish some implications for the future of climatological and astronomical research. Microbiological organisms have an effect on precipitation and other aspects of biological and human life. Whereas the first mention of a scientific interest in literature of microbes in the air occurred in the Netherlands in 1676, an interest in bacteria as condensation nuclei emerged first in 1973, when such bacteria were isolated from decomposing leaves. In 1978, Soviet researchers sought to identify the upper boundary of the biosphere, and detected the presence of fungi as high as 77 km. Biological matter have since been found to compose perhaps one quarter of the aerosols, or suspended solids in the atmosphere. Examples of atmospheric aerosols of biological origin include pollen, bacteria, fungi, spores, marine plankton, plant particles and decaying vegetation, viruses, protein crystals, and other faunal fragments including dandruff, hair or fur, and animal skin fragments. A thorough literature review was conducted on bacteria and other microbial life collected from the troposphere and higher elevations by various means, up to the year 2018, the first submission of this draft paper. Ground samples were sometimes included if there was good reason to suspect that the bacteria originated from or journeyed to higher altitudes within the atmosphere. The review focused on species isolated from higher levels of the atmosphere, such as the upper troposphere, stratosphere, or even mesosphere. The “year identified” column of each table listed was noted as the year of publication for the relevant paper discussing each identified genera and species. Listings were made when at least the genus was identifiable, at least tentatively.

Ongoing global change and its direct environmental impacts, in addition to securing economic transition to the post-oil era, could trigger complex socio-economic and political crises in oil-dependent economies of the Persian Gulf Region (PGR). To evaluate the role of climate change and related policies in degrading the environment and its socio-economic impacts in the PGR, we have used a variety of available global datasets and published data. The results show that the countries of the PGR pursue some types of socio-economic reforms to alleviate the impacts of climate change. However, it seems that these attempts are not compatible with the environment's capacity. The main problem stems from the fact that political differences between the PGR nations prevent them from managing the Persian Gulf environment as an integrated natural system and consequently they have to limit their efforts within their borders, regardless of what happens in other parts of the system. The shift to alternative revenue sources by the countries needs socioeconomic preparedness while there are environmental obstacles, political tensions and geopolitical rivalries. Unless there is a cooperative approach to mitigate the effects of climate change, accompanied by a reorientation of PGR economies, the situation is likely to worsen rather than improve. To address the challenges of climate change, integrated regional collaborations are needed. Collective action, such as more investment in regional research and development and education, is required if the PGR is to successfully transition from a commodity-based to a knowledge-based economy.

Long-term data characterizing the oceans' biological carbon pump are essential for understanding impacts of climate variability on marine ecosystems. The "Bakun upwelling intensification hypothesis" suggests intensified coastal upwelling due to a greater land-sea temperature gradient influenced by global warming. We present long time series of bathypelagic (approximately 1,200-3,600 m) particle fluxes from a coastal (CBeu: 2003-2016) and an offshore (CBmeso: 1988-2016) sediment trap setting located in the Canary Current upwelling. Organic carbon (C org) and biogenic opal (BSi, diatoms) fluxes were twofold to threefold higher at the coastal upwelling site compared to the offshore site, respectively, and showed higher seasonality with flux maxima in spring. A relationship between winter and spring BSi fluxes to the North Atlantic Oscillation index was best expressed at the offshore site CBmeso. Lithogenic (dust) fluxes regularly peaked in winter when frequent low-altitude dust storms and deposition occurred, decreasing offshore by about threefold. We obtained a high temporal match of short-term peaks of BSi and dust fluxes in winter to spring at the inner site CBeu. We found synchronous flux variations at both sites and an anomalous year 2005, characterized by high BSi and C org fluxes under a low North Atlantic Oscillation. C org and BSi fluxes revealed a decreasing trend from 2006 to 2016 at the coastal site CBeu, pointing to coastal upwelling relaxation during the last two decades. The permanent offshore upwelling zone of the deflected Canary Current represented by the flux record of CBmeso showed no signs of increasing upwelling as well which contradicts the Bakun hypothesis.

atmospheric dust loads. Poor agricultural practices were implicated for triggering widespread eolian erosion and heightened dust emissions, but this assumption is called into question. This study classified land surface changes in southwest Kansas from aerial images taken in 1936 and 1939 to infer surficial processes, dust sources, and associated emissivity. In total, seven distinctive surface classes were identified from an ArcGIS analysis of spectral reflectance values connected to surface vegetation cover and eolian activity, demonstrating a strikingly heterogeneous landscape response to the drought. Stratigraphic studies indicate accumulation of up to 4 m of eolian sand in places with erosion of a subjacent silty pre-1930s soil surface. Potential dust
emissivity estimates for particulate matter were derived from the distribution of classified land surfaces and from empirical relations on analogous dust emissive surfaces in the western US. Over 60% of total suspended particles in 1939 were inferred to be derived from uncultivated sandy surfaces and eolian landforms within the study area, with the remainder from human-modified surfaces. The PM2.5 and PM10 emissivity estimates for a single dust event with winds over 6 m s−1 in the study area were 510–4514 and 4700–41,607 μg m−3 d−1, respectively, similar in magnitude to current dust storm events
from North Africa and East Asia. Drought frequency is forecast to increase in late 21st century, potentially with greater severity than the Dust Bowl and may be associated with magnitude increase in atmospheric dust loads.

Mineral dust is an important component of Earth’s climate system and biogeochemical cycles on a global scale. In order to  nderstand the relationship between climate processes in the source areas  and the properties of aerosols at distant receptor sites, we must be able to identify the source provenance of dust. Here we present a multiproxy study that characterizes the temporal variability in the geochemical composition of long-range African dust (LRAD)
collected between 2003 and 2011 in the trade winds on the Caribbean island of Barbados. We find systematic differences between Sr-Nd-Hf isotopic composition and rare earth element
anomalies of individual dust events and evidence of seasonal shifts in dust source activity and transport. These results indicate that coherent geochemical source signatures of LRAD can be preserved even after transport across thousands of kilometers. We investigated the possibility of identifying the potential source areas through comparisons with literature data. However,
these data are almost entirely based on measurements of soil and sediment samples; this could lead to biases because of soil-aerosol particle size and composition differences. Nonetheless, our data suggest that many samples are linked to sources in Mali and sub-Saharan regions. Radiogenic Nd-Hf composition of aerosols can potentially be a useful proxy to study the proximity of mineral dust sources to depositional sites. In order to establish firmer links between LRAD and dust source areas, however, we require much more data on the geochemical composition of aerosols from potential source areas in North Africa.

Accurate and precise morphometric modelling
can be extended to past eruptions after a careful palaeogeomorphological
reconstruction of volcanic landforms in
an oceanic island. This reconstruction was used to derive
the pre-, post-eruption and present-day digital elevation
models (DEM). The correct pixel size, interpolation
method and quality of these DEMs are discussed. The
process in a Geographical Information System framework
of the geological information of cone, lava flow and tephra
fall deposits together and the aforementioned DEMs
allowed the determination of main morphological features
of these volcanic landforms and their derivatives. The
calibration and validation of morphometric modelling were
performed on simulated volcanic landforms, and verified
by a case study: a typical Holocene monogenetic basaltic
eruption at Gran Canaria Island (Spain).

Mineral dust is transported in the atmosphere and deposited in oceans, ice sheets and the terrestrial biosphere. Temporal changes in locations of dust source areas and transport pathways have implications for global climate and biogeochemical cycles. The chemical and physical characterization of the dust record preserved in ice cores is useful for identifying of dust source regions, dust transport, dominant wind direction and storm trajectories. Here, we present a 50,000-year geochemical characterization of mineral dust entrapped in a horizontal ice core from the Taylor Glacier in East Antarctica. Strontium (Sr) and neodymium (Nd) isotopes, grain size distribution, trace and rare earth element (REE) concentrations, and inorganic ion (Cl À and Na þ) concentrations were measured in 38 samples, corresponding to a time interval from 46 kyr before present (BP) to present. The Sr and Nd isotope compositions of insoluble dust in the Taylor Glacier ice shows distinct changes between the Last Glacial Period (LGP in this study ranging from ~46.7e15.3 kyr BP) the early Holocene (in this study ranging from ~14.5e8.7 kyr BP), and zero-age samples. The 87 Sr/ 86 Sr isotopic composition of dust in the Taylor Glacier ice ranged from 0.708 to 0.711 during the LGP, while the variability during the early Holocene is higher ranging from 0.707 to 0.714. The ε Nd composition ranges from 0.1 to À3.9 during the LGP, and is more variable from 1.9 to À8.2 during the early Holocene. The increased isotopic variability during the early Holocene suggests a shift in dust provenance coinciding with the major climate transition from the LGP to the Holocene. The isotopic composition and multiple physical and chemical constraints support previous work attributing Southern South America (SSA) as the main dust source to East Antarctica during the LGP, and a combination of both local Ross Sea Sector dust sources and SSA after the transition into the Holocene. This study provides the first high time resolution data showing variations in dust provenance to East Antarctic ice during a major climate regime shift, and we provide evidence of changes in the atmospheric transport pathways of dust following the last deglaciation.

Composition of dust transported locally, regionally, and globally has influences on human health, ecosystem functioning, and biogeochemical cycling. This study aimed to characterize differences between dust and soil samples at a dust source in the eastern Great Basin of Utah, USA. Dust and soil samples were collected from the Sevier Dry Lake, a known dust producing playa in this region. Samples were resuspended in the laboratory and collected using an 8-stage Davis Rotating-drum Universal-size-cut Monitoring (DRUM) impactor. Collected samples were analyzed for elemental concentration using Synchrotron X-Ray Fluorescence (SXRF). Element concentration was normalized and analyzed for enrichment relative to major soil element Al. Dust and soil samples contain similar enrichments of major soil elements including Si, Fe, Ca, K, Mg, and Ti. However, dust samples were significantly more enriched in Na derived from the surface salts of the Sevier Dry Lake. Minor soil elements (all elements analyzed apart from the major soil elements) were generally more enriched in dust samples and had larger enrichment values (up to 104) than seen in previous studies. Further, for dust and soil samples, the fine fraction (<2.5 μm) was more enriched in minor soil elements than the coarse fraction (2.5–10 μm). Dust from this source, containing elevated levels of potentially hazardous elements, degrades air quality in the Salt Lake City metropolitan area of Utah and is deposited in the alpine ecosystems of the Wasatch Mountains.

Dust storms are one of the main environmental challenges, particularly in West Asian Region. The phenomenon has great harmful impacts on the countries of the region including Iran, Iraq, Syria, Kuwait, and other countries around Persian Gulf. Intensification of the phenomenon in recent years made it necessary to find a suitable solution to combat against the devastating events. Therefore, the headquarter of water resources development, drought, erosion and environment assigned a project entitled “Investigation of Dust Storms in West Asian Region” to Geoinformatic Research Institute (GRI) of the University of Tehran in order to study the regional phenomenon. United Nations Environmental Program (UNEP) Regional Office of West Asia (ROWA) also supported this project because of its regional nature and the need for participation from national, regional and international organizations.
The output and outcomes of this project entitled “Investigation of Dust Storms in West Asian Region” is three reports:
 Primary Investigation of Dust Storm Sources in West Asia (With an Emphasis on Storms Came to Iran)
 Analysis of Fundamentals, Identification Criteria, and Modeling of Dust Storms (With emphasis on West Asia Region)
 Investigation of factors of dust storms and solutions for combating (With emphasis on West Asia Region)
Members of the team are greatly thankful to kind cooperation of all professors, students, colleagues, and the experts who assisted in conduction of this project. The team is also especially grateful to vice-president for science and technology affairs of Islamic republic of Iran and UNEP-ROWA. All kinds of criticism and suggestions are warmly welcomed by the team members.
Dr. Hossein Ali Bahrami
Secretariat of the headquarter of water resources development, drought, erosion and environment technologies (vice-president for science and technology affairs of Islamic republic of Iran)
Dr. Ali Darvishi Bolourani
The head of International Geoinformatic Reseach Institute of the University of Tehran (GRI) and the executer of the project
Dr. Abdol Majid Hadad
Environemntal Program of United Nations, Regional Office of West Asia (UNEP-ROWA)

Abstract
Background
One of the natural phenomena which have had considerable impacts on various regions of the
world, including Iran, is “dust storm”. In recent years, this phenomenon has taken on new
dimensions in Iran and has changed from a local problem to a national issue. This study is an
attempt to investigate the formation of the dust storms crossing the Western Iran.
Methodology
To find the sources of the dust storms entering Iran, first we examine three determined dust
paths in the region and their temporal activities, using MODIS satellite images. Then, four
regions were identified as dust sources through soil, land cover and wind data. Finally,
atmospheric analyses are implemented to find synoptic patterns inducing dust storms.
2
Results and discussion
Source 1 has covered the region between the eastern banks of Euphrates and western banks of
Tigris. Source 2 is in desert area of western and south-western Iraq. Finally source 3 is
bounded in eastern and south-eastern deserts of Saudi Arabia called Rub-Al-Khali desert, or
Empty Quarter. Moreover, south-eastern part of Iraq (source 4) was also determined as a
secondary source which thickens the dust masses originating from the above mentioned
sources. The study of synoptic circulations suggests that the dust storms originating from
source 1 are formed due to the intense pressure gradient between the low-pressure system of
Zagros and a high-pressure cell formed on Mediterranean Sea. The dust events in sources 2
and 3 are outcomes of the atmospheric circulations dominant in the cold period of the year in
mid-latitudes.

Abstract. The transport of dust and sand by wind is a potent erosional force, creates sand dunes and ripples, and loads the atmosphere with suspended dust aerosols. This article presents an extensive review of the physics of wind-blown sand and dust on Earth and Mars. Specifically, we review the physics of aeolian saltation, the formation and development of sand dunes and ripples, the physics of dust aerosol emission, the weather phenomena that trigger dust storms, and the lifting of dust by dust devils and other small-scale vortices. We also discuss the physics of wind-blown sand and dune formation on Venus and Titan.

The Iberian Central System (ICS) is a clue region to reveal Mediterranean/Atlantic inferences over Iberia. We present a multidisciplinary study from western Spain conducted in the Navamuño depression (ND), covering the last 16.8 ka (cal BP). A reconstruction of the palaeotemperature from the resulting geochemical data highlights four cold and dry intervals, namely, the Oldest Dryas, Older Dryas, Intra-Allerød Cold Period (IACP), and the Younger Dryas, along with warmer intervals: the Bølling (14.7–14 ka) and the Allerød (12.9–12.6 ka); however, the Greenland Interstadial GI-1c (13.4–13.1 ka) is barely distinguishable in the ND. Despite the shortage of biomass to sustain fire, the earliest charcoals are from ~14.4–13.8 ka. Evidence of ash/dust events overprinting the geochemical background starts at ~13.8–12.8 ka. Significant fire activity in the Early Holocene at ~11.7–10.6 ka affected the ND, matching the westernmost ICS data. This period includes short oceanic spells inferred from Cl peaks at ~10.9–10.2 ka and three cold intervals at 11.4, 9.3, and 8.2 ka disrupted the progressive temperature increase. The Mid-Holocene showed a continuously increasing trend towards an arid climate, peaking at 4.2 ka under a pervasive dust influx from North Africa, which has prevailed since almost ~7.9 ka. A prominent volcanic event at ~6.8–5.8 ka is in Navamuño and Roñanzas (Asturias, N Spain; Gallego et al., 2013) identified from heavy metal-rich layer, synchronous with the last known eruption of the Calatrava volcanic field (South-Central Spain; Poblete-Piedrabuena et al., 2019). This volcanic eruption could affect many other regions half north of Iberia. The pervasive presence of oceanic aerosols in the last three millennia (2.8 ka ~) allowed the formation of a Cl-rich peat layer during the Ibero-Roman humid period ~2.1 ka, before a changing around ~0.4 ka toward colder and drier conditions at the Little Ice Age (LIA) period.

Loess accumulation and paleosol formation are important Quaternary geoarchives in northern Iran. Two loess-paleosol sequences at Mobarakabad and Aghband were examined using soil morphology and micromorphology, mineralogy, magnetic susceptibility (MS), free Fe oxides and calcium carbonate equivalent. The loess-paleosol sequences provide a record of changes in paleo-rainfall in the northern Iran. Micromorphological and MS differences between the loess and paleosols in the sections reflect changes in climate. The different behaviors of magnetic susceptibility between Aghband and Mobar-akabad loess are mainly produced by their different pedogenic environments, topography and climatic conditions. As a result, the MS at the Mobarakabad section is much higher than at Aghband. Paleoeco-logical reconstructions coupled with magnetic depletion in paleosols at Mobarakabad suggest a wetter climate dominating during the formation of the paleosols.

Dust in Greenland ice cores is used to reconstruct the activity of dust emitting regions and atmospheric circulation. However, the source of dust material to Greenland over the last glacial period is the subject of considerable uncertainty. Here we use new clay mineral and <10 µm Sr-Nd isotopic data from a range of Northern Hemisphere loess deposits in possible source regions alongside existing isotopic data to show that these methods cannot discriminate between two competing hypothetical origins for Greenland dust: an East Asian and/or Central European source. By contrast, Hf isotopes (<10 µm fraction) of loess samples show considerable differences between the potential source regions. We attribute this to a first-order clay mineralogy dependence of Hf isotopic signatures in the finest silt/clay fractions, due to absence of zircons. As zircons would also be absent in Greenland dust, this provides a new way to discriminate between hypotheses for Greenland dust sources.

A record of dust deposition events between 2009 and 2012 on Mt. Elbrus, Caucasus Mountains derived from a snow pit and a shallow ice core is presented for the first time for this region. A combination of isotopic analysis, SEVIRI red-green-blue composite imagery, MODIS atmospheric optical depth fields derived using the Deep 5 Blue algorithm, air mass trajectories derived using the HYSPLIT model and analysis of meteorological data enabled identification of dust source regions with high temporal (hours) and spatial (cf. 20-100 km) resolution. Seventeen dust deposition events were detected; fourteen occurred in March-June, one in February and two in October. Four events originated in the Sahara, predominantly in north-eastern Libya and eastern Al-

Interactions of desert dust and air pollution over the eastern Mediterranean (EM) have been studied, focusing on two distinct dust transport events on 22 and 28 September 2011. The atmospheric chemistry-climate model EMAC has been used at about 50 km grid spacing, applying an online dust emission scheme and calcium as a proxy for dust reactivity. EMAC includes a detailed tropospheric chemistry mechanism, aerosol microphysics and thermodynamics schemes to describe dust "aging". The model is evaluated using ground-based observations for aerosol concentrations and aerosol optical depth (AOD) as well as satellite observations. Simulation results and back trajectory analysis show that the development of synoptic disturbances over the EM can enhance dust transport from the Sahara and Arabian deserts in frontal systems that also carry air pollution to the EM. The frontal systems are associated with precipitation that controls the dust removal. Our results show the importance of chemical aging of dust, which increases particle size, dust deposition and scavenging efficiency during transport, overall reducing the lifetime relative to non-aged dust particles. The relatively long travel periods of Saharan dust result in more sustained aging compared to Arabian dust. Sensitivity simulations indicate 3 times more dust deposition of aged relative to pristine dust, which significantly decreases the dust lifetime and loading.

Isotopic characterization of aerosol mineral particles (atmospheric dust) of varying sizes is essential in
classifying source areas, and for determining the source of dust deposited over oceans and icesheets. However,
the effect of atmospheric transport on radiogenic isotopic compositions is not well constrained, making
provenance interpretation difficult. In order to investigate the isotopic variability of 176Hf/177Hf, 87Sr/86Sr and
143Nd/144Nd we analyzed eight airborne dust samples in two size fractions collected along a cross-Atlantic
transect through a dust storm originating in the Sahara in late 2002. Past measurements of 176Hf/177Hf, 87Sr/86Sr
and 143Nd/144Nd of dust have focused primarily on coarse sized particles (b30 μm), whereas far field deposition
is primarily finer particles (b2 μm). Strontium or neodymium isotopic sorting based on distance is not evident
in our dataset; however, the combined isotopic ratios of the dust collected suggest a Saharan origin. Hafnium
isotopic compositions show an east to west trend towards more radiogenic compositions across the Atlantic,
suggesting grain and mineral sorting during dust transport along the ~4000 km transect. Transport models
with variable dust particle diameter and wind speed demonstrate the preferential depletion of the highdensity
mineral zircon during transport of dust from the source area. The transport model combined with a
simple two component mixing model show that the Hf isotopic composition changes can be explained by the
loss of the mineral zircon during transport. Modeling of this “zircon effect” with distance from the dust source
in the Hf isotopic composition of marine, terrestrial and glacial dust deposits may reveal additional information
concerning dust transport and sources in the geologic past.

Earthquake Environmental Effects (EEE), including all phenomena generated by a seismic event in the natural environment, have been included in the macroseismic intensity assessment since the very beginning, in order to define the highest degrees of the intensity scales (eg, Ferrari Postpischl, 1979; Sieberg, 1912; 1932). They can be categorized in primary effects, ie the surface expression of the seismogenic source, and secondary effects, mostly induced by the vibratory ground motion. Their use for intensity assessment has ...

In most remote and unmonitored places, little is known about the characteristics of daytime turbulent activity. Few processes render the optically transparent atmospheres of Earth and Mars visible; put more plainly, without clever instruments it is difficult to ‘‘see the unseen’’. To address this, we present a pilot study of images of martian dust devils (DDs) testing the hypothesis that DD height and spacing correlates with the thickness of the planetary boundary layer (PBL), h. The survey includes Context Camera (CTX) images from a 580 x 590 km^2 area (196–208ºE, 30–40ºN) in northern Amazonis Planitia, spanning ~3.6 Mars Years (MY) from Ls = 134.55º, MY 28 (13 November 2006) to Ls = 358.5º, MY 31 (28 July 2013). DD activity follows a repeatable seasonal pattern similar to that found in previous surveys, with a distinct ‘‘on’’ season during local summer, beginning shortly before the northern spring equinox (Ls = 0º) and lasting until just after the northern fall equinox (Ls = 180º).

DD heights measured from shadow lengths varied considerably, with median values peaking at local midsummer. Modeled PBL heights, constrained by those measured from radio occultation data, follow a similar seasonal trend, and correlation of the two suggests that the martian PBL thickness is approximately 5 times the median DD height. These results compare favorably to the limited terrestrial data available.

DD spacing was measured using nearest neighbor statistics, following the assumption that because convection cell widths have been measured to be ~1.2 ± 0.2h (Willis, G.E., Deardorff, J.W. [1979]. J. Geophys. Res. 84(C1), 295–302), a preference for DD formation at vertices of convection cells intersections could be used to estimate the PBL height. During local spring and summer, the DD average nearest neighbor (ANN) ranged from ~1to 2h, indicating that DD spacing does indeed correlate with PBL height. However, this result is complicated by two factors: (1) convection cell spacing estimates indicate that the observed DD distributions undersample the possible grid of cell vertices in each CTX image, and (2) comparison of the ANN with a random distribution shows that the most closely-spaced DD distributions exhibit some clustering; we propose that this clustering demonstrates that many of the observed DDs are located along convection cell walls, in addition to cell vertices.

Episodes of high levels of particulate matter (PM) in Reykjavík occur several times a year. The main sources of daily variation in PM are traffic or highly localized (e.g. construction) sources, however several episodes have been identified where these are not the cause. Examining PM 10 (diameter < 10 mm) levels around the time when dust storms are seen on satellite images, and verifying that the weather conditions are favorable for the duration of the high levels of PM (>50e100 mg m À3 ; 30-min average), demonstrates that dust storms are the source of these increased levels of PM 10 . Since satellite coverage is sparse, visual confirmation of many such peaks in PM 10 cannot be achieved. The level of pollution measured in Reykjavík during dust storms indicates that at least 200 kg s À1 of PM 10 sized material is being eroded and transported away from sand plains w110 km away e this equates to an emission rate of 35 g m 2 h À1 . The source regions for dust storms in Iceland are the sandur areas on the southern coast of Iceland, and regions close to the glaciers. With climate warming, and fast retreating glaciers, the potential source regions in Iceland are rapidly increasing.

1] The vertical distribution of dust in Mars' atmosphere is a critical unknown in the simulation of its general circulation and a source of insight into the lifting and transport of dust. Zonal average vertical profiles of dust opacity retrieved by Mars Climate Sounder show that the vertical dust distribution is mostly consistent with Mars general circulation model (GCM) simulations in southern spring and summer but not in northern spring and summer. Unlike the GCM simulations, the mass mixing ratio of dust has a maximum at 15-25 km over the tropics during much of northern spring and summer: the high-altitude tropical dust maximum (HATDM). The HATDM has significant and characteristic longitudinal variability, which it maintains for time scales on the order of or greater than those on which advection, sedimentation, and vertical eddy diffusion would act to eliminate both the longitudinal and vertical inhomogeneity of the distribution. While outflow from dust storms is able to produce enriched layers of dust at altitudes much greater than 25 km, tropical dust storm activity during the period in which the HATDM occurs is likely too rare to support the HATDM. Instead, the lifting of dust by mesoscale circulations over topography, pseudomoist convection due to the solar heating of dust, and scavenging of dust by water ice are all possible drivers of the HATDM. Citation: Heavens, N. (2011), Vertical distribution of dust in the Martian atmosphere during northern spring and summer: High-altitude tropical dust maximum at northern summer solstice,

Mineral dust is transported in the atmosphere and deposited in oceans, ice sheets and the terrestrial biosphere. Temporal changes in locations of dust source areas and transport pathways have implications for global climate and biogeochemical cycles. The chemical and physical characterization of the dust record preserved in ice cores is useful for identifying of dust source regions, dust transport, dominant wind direction and storm trajectories. Here, we present a 50,000-year geochemical characterization of mineral dust entrapped in a horizontal ice core from the Taylor Glacier in East Antarctica. Strontium (Sr) and neodymium (Nd) isotopes, grain size distribution, trace and rare earth element (REE) concentrations, and inorganic ion (Cl À and Na þ ) concentrations were measured in 38 samples, corresponding to a time interval from 46 kyr before present (BP) to present. The Sr and Nd isotope compositions of insoluble dust in the Taylor Glacier ice shows distinct changes between the Last Glacial Period (LGP in this study ranging from ~46.7e15.3 kyr BP) the early Holocene (in this study ranging from ~14.5e8.7 kyr BP), and zero-age samples. The 87 Sr/ 86 Sr isotopic composition of dust in the Taylor Glacier ice ranged from 0.708 to 0.711 during the LGP, while the variability during the early Holocene is higher ranging from 0.707 to 0.714. The ε Nd composition ranges from 0.1 to À3.9 during the LGP, and is more variable from 1.9 to À8.2 during the early Holocene. The increased isotopic variability during the early Holocene suggests a shift in dust provenance coinciding with the major climate transition from the LGP to the Holocene. The isotopic composition and multiple physical and chemical constraints support previous work attributing Southern South America (SSA) as the main dust source to East Antarctica during the LGP, and a combination of both local Ross Sea Sector dust sources and SSA after the transition into the Holocene. This study provides the first high time resolution data showing variations in dust provenance to East Antarctic ice during a major climate regime shift, and we provide evidence of changes in the atmospheric transport pathways of dust following the last deglaciation.

Mineral dust is transported in the atmosphere and deposited in oceans, ice sheets and the terrestrial biosphere. Temporal changes in locations of dust source areas and transport pathways have implications for global climate and biogeochemical cycles. The chemical and physical characterization of the dust record preserved in ice cores is useful for identifying of dust source regions, dust transport, dominant wind direction and storm trajectories. Here, we present a 50,000-year geochemical characterization of mineral dust entrapped in a horizontal ice core from the Taylor Glacier in East Antarctica. Strontium (Sr) and neodymium (Nd) isotopes, grain size distribution, trace and rare earth element (REE) concentrations, and inorganic ion (Cl À and Na þ) concentrations were measured in 38 samples, corresponding to a time interval from 46 kyr before present (BP) to present. The Sr and Nd isotope compositions of insoluble dust in the Taylor Glacier ice shows distinct changes between the Last Glacial Period (LGP in this study ranging from~46.7e15.3 kyr BP) the early Holocene (in this study ranging from~14.5e8.7 kyr BP), and zero-age samples. The 87 Sr/ 86 Sr isotopic composition of dust in the Taylor Glacier ice ranged from 0.708 to 0.711 during the LGP, while the variability during the early Holocene is higher ranging from 0.707 to 0.714. The ε Nd composition ranges from 0.1 to À3.9 during the LGP, and is more variable from 1.9 to À8.2 during the early Holocene. The increased isotopic variability during the early Holocene suggests a shift in dust provenance coinciding with the major climate transition from the LGP to the Holocene. The isotopic composition and multiple physical and chemical constraints support previous work attributing Southern South America (SSA) as the main dust source to East Antarctica during the LGP, and a combination of both local Ross Sea Sector dust sources and SSA after the transition into the Holocene. This study provides the first high time resolution data showing variations in dust provenance to East Antarctic ice during a major climate regime shift, and we provide evidence of changes in the atmospheric transport pathways of dust following the last deglaciation.

The influence of atmospheric dust on climate and biogeochemical cycles in the oceans is well understood but poorly quantified. Glacial atmospheric dust loads were generally greater than those during the Holocene, as shown, for example, by the covariation of dust fluxes in the Equatorial Pacific and Antarctic ice cores. Nevertheless, it remains unclear whether these increases in dust flux were associated with changes in sources of dust, which would in turn suggest variations in wind patterns, climate or paleo-environment. Such questions can be answered using radiogenic isotope tracers of dust provenance.
Here, we present a 160-kyr high-precision lead isotope time-series of dust input to the Eastern Equatorial Pacific (EEP) from core ODP Leg 138, Site 849 (0°11.59'N, 110°31.18'W). The Pb isotope record, combined with Nd isotope data, rules out contributions from Northern Hemisphere dust sources, north of the Intertropical Convergence Zone, such as Asia or North Africa/Sahara; similarly, eolian sources in Australia, Central America, the Northern Andes and Patagonia appear insignificant based upon the radiogenic isotope data.
Fluctuations in Pb isotope ratios throughout the last 160 kyr show, instead, that South America remained the prevailing source of dusts to the EEP. There are two distinct South American Pb isotope end-members, constrained to be located in the south Central Volcanic Zone (CVZ, 22°S-27.5°S) and the South Volcanic Zone (SVZ, 33°S-43°S), with the former most likely originating in the Atacama Desert. Dust availability in the SVZ appears to be related to the weathering of volcanic deposits and the development of ash-derived Andosols, and influenced by local factors that might include vegetation cover. Variations in the dust fluxes from the two sources are in phase with both the dust flux and temperature records from Antarctican ice cores. We show that the forcing of dust provenance over time in the EEP overall is influenced by high-southerly-latitude climate conditions, leading to changes in the latitudinal position and strength of the South Westerlies as well as the coastal winds that blow northward along the Chilean margin. The net result is a modulation of dust emission from the Atacama Desert and the SVZ via a northward migration of the South Westerlies during cold periods and southward retreat during glacial terminations.

In the past decade, West Asia has witnessed more frequent and intensified dust storms affecting Iran and Persian Gulf countries. Employing a varying threshold that takes into account systematic differences between TOMS and OMI data, TOMS-OMI Aerosol Index data are used to identify long-term changes in the horizontal distribution of dust storms in West Asia from 1980 to present. The northwest of Iraq and east of Syria are identified as emerging dusty areas, whereas east of Saudi Arabia and southeast of Iraq are identified as permanent dusty areas, including both dust sources and affected areas. Whereas the frequency of dust events increased slightly in the permanent dusty areas, it increased markedly in the emerging dusty areas. As expected, the frequency of dust events is highest in June and July. The dust source areas are identified as the Iraq-Saudi Arabia boundary region and (recently) the northwest of Iraq, using MODIS deep blue aerosol optical depth data. Subsequently, a lagged correlation was implemented between identified dust sources and whole West Asia to determine the main paths and receptors of intense dust storms. Accordingly, southwest of Iran and Persian Gulf countries were determined as main receptors of summertime dust storms in West Asia. During spring, dust storms mostly hit the northern half of the region and reach to the Caspian Sea. Analyzing atmospheric patterns, Shamal and Frontal patterns were found as dominant atmospheric circulations simultaneous with summertime and springtime dust storms, respectively.

The 8th International Workshop on Sand/Duststorms and Associated Dustfall (DUSTworkshop8) will be held in Lisbon, May 2016.

After the success of the previous editions, DUSTworkshop8 will be held in Lisbon, Portugal, on 1st – 4th of May 2016 under the auspices of Centro de Ciências e Tecnologias Nucleares (C2TN) from Instituto Superior Técnico – Universidade de Lisboa and Centre for Environmental and Marine Studies (CESAM) from University of Aveiro.
The theme of DUSTworkshop8 is "Advances on research and knowledge on sand and dust storms and their impacts on environment, weather and climate".

The goal of DUSTworkshop8 is to bring international research activities/outcomes together and to discuss how to enhance our understanding of dust storm mechanisms and their links and feedbacks between desert dust, air quality, radiation, clouds, water budget and health impacts. One of the major objectives is to bring together scientists working on dust from worldwide, exchange information on hot research topics and to promote international collaborative efforts between research groups, institutions and agencies.

The Workshop will consist of plenary talks, oral presentations, round table discussions and poster presentations. The scope of the workshop includes studies using modeling, measurements and analyses (in situ and remote sensing) in the following topical areas:
• Source definition and properties of dust;
• Dust particle size and composition issues;
• Dust transport, mixing with anthropogenic pollutants and aging;
• Aerosol-radiation-cloud-precipitation interactions;
• Dust and climate interactions;
• Dust and ocean productivity;
• Modeling and prediction;
• Environment impact assessment;
• Health impact assessment.
This is an excellent opportunity to showcase your research, findings and practices in the various thematic listed above. We believe that your contribution to this field is unparalleled and your presentation at this conference will be of great benefit.

For submission of abstracts, please visit this link! The deadline for submission is 15th December 2015!

More information will be available soon. Meanwhile, save the date!

DUSTworkshop8 National Organizing Committee
C2TN, Instituto Superior Técnico
Estrada Nacional 10, ao  km 139,7
2695-066 Bobadela LRS
Portugal
Email: dustworkshop8@ctn.tecnico.ulisboa.pt
Website: http://www.dustworkshop8.ctn.tecnico.ulisboa.pt
Facebook webpage: www.facebook.com/dustworkshop8

1] The vertical distribution of dust in Mars's atmosphere is a critical and poorly known input in atmospheric physical and chemical models and a source of insight into the lifting and transport of dust and general vertical mixing in the atmosphere. We investigate vertical profiles of dust opacity retrieved from limb observations by Mars Climate Sounder during the relatively dust-clear Martian northern summer of 2006-2007 (L s = 111°-177°of Mars year (MY) 28) and Martian northern spring and summer of 2007-2008 (L s = 0°-180°of MY 29).

Airborne dust affects all aspects of human life. The sources of dust have high spatial variation and a better quantification of dust emission helps to identify remediation measures. Orographic and statistical source functions allow a better estimation of dust emission fluxes in coarse-scale modeling, but a high-resolution source function is necessary to represent the highly heterogeneous nature of dust sources at the finer scale. Here we use a newly developed highresolution (~ 500 m) source function in WRF-Chem to simulate dust emission over the Middle East and North Africa, and evaluate our simulated results against observations. Using a 4 km grid spacing, we also simulate the emission and transport of dust originating from the Tigris-Euphrates basin, one of the most important regional dust sources, and quantify the effects of this source on the air quality of the entire Arabian Peninsula. Results show that the use of new source function effectively represents the key dust sources, and provides reasonable estimates of dust optical depth and concentrations. We find that the atmospheric dust originating from the Tigris-Euphrates basin alone exceeds the PM10 air quality standards in several downwind cities. Our results have broader environmental implications and indicate that the mobilization of depleted uranium (DU) deposited in Kuwait and Southern Iraq during the Gulf War (1991) could potentially affect the urban centers over the peninsula, albeit in low concentrations. Our results suggest that an integrated and coordinated management of the Tigris-Euphrates basin is necessary to maintain good air quality across the Arabian Peninsula.

Field experiments were conducted in the Nellis Dunes Recreational Area (Nevada, USA) to study the dynamics of dust clouds produced by off-road vehicle (ORV) driving. Tests were performed with a 4-wheeler (quad), for 3 driving speeds between 24 and 40 km h -1 and for 7 different types of surfaces. Fine as well as coarse-grained surfaces were investigated in the tests. Results show that concentration of PM10 (particles <10 μm, which are the most easily inhaled) behind an ORV can be as high as 160 mg m -3 or even more at nose level of quad drivers and passive recreants standing near an ORV trail. ORV generated dust clouds are characterized by a main wave of high concentration followed by an exponential decrease with irregularities (secondary waves) until background concentration has again been reached. Peak concentrations usually occur between 5 and 7 seconds after the passage of an ORV and are higher for silty surfaces than for sandy surfaces. Under no-wind and headwind conditions it takes at least one minute before PM10 concentration has returned to the background level. For tailwind the duration of elevated concentration is of the order of 30 seconds. For winds blowing obliquely to the driving path it is only a few seconds. Elevated PM10 concentrations may occur up to several hundreds of meters behind an ORV, even if no dust is visually noticeable. In-echelon driving is thus strongly dissuaded unless appropriate protection is worn against inhaling the dust.