scholarly journals Test of Dust Emission Over the Middle East

2020 ◽  
Author(s):  
Mokhammad Suleiman Mostamandi ◽  
Georgiy Stenchikov ◽  
Alexander Ukhov ◽  
Illia Shevchenko ◽  
Johann Engelbrecht ◽  
...  
Keyword(s):  
Middle East ◽  
Dust Emission ◽  
Satellite Observations ◽  
Passive Samplers ◽  
Dust Particles ◽  
Grid Spacing ◽  
Dust Deposition ◽  
Regional Models ◽  
Order Of Magnitude ◽  
Micro Pulse Lidar

<p>Abstract</p><p>The dust emission simulated within the up-to-date global and regional models differs by almost an order of magnitude. The models are tuned to reproduce the observed aerosol optical depth (AOD) that, with some caveats, reflects the dust mass retained in the atmosphere. However, the amount of dust suspended in the atmosphere is controlled independently by the dust emission and deposition; therefore, only AOD observations are insufficient to constrain both these processes. To calculate the dust emission over the Middle East (ME), in this study, we employ dust deposition observations, AERONET AOD, micro-pulse lidar, and satellite observations to constrain the WRF-Chem simulations. The dust deposition is measured on a monthly bases for 2015-2019 using passive samplers over six sites over land and the sea. We compare the WRF-Chem simulations, conducted with 10-km grid spacing, with the recent MERRA-2 and CAMS reanalysis. WRF-Chem is configured with the GOCART dust scheme. We calculate the meteorological and aerosol initial and boundary conditions using the MERRA-2 reanalysis. </p><p>We evaluated the dust regional mass balance controlled by emission, deposition, and cross-boundary transport. The smallest dust particles are transported at vast distances while the heaviest ones deposit inside of the domain. Since the model accounts for dust particles with radii<10 um, we process the deposition samples to extract the weight of particles smaller than 10 um. WRF-Chem was tuned to reproduce the observed AOD and monthly deposition of dust particles with radii < 10 um. We found that the ME dust emission comprises about 30% of the global annual dust emission. MERRA-2 underestimates the ME dust emission by about 15%.</p>

scholarly journals Dust Deposition on the Gulf of California Caused by Santa Ana Winds

Atmosphere ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 275 ◽  
Author(s):  
Christian A. Álvarez ◽  
José N. Carbajal ◽  
Luis F. Pineda-Martínez ◽  
José Tuxpan ◽  
David E. Flores
Keyword(s):  
Gulf Of California ◽  
Dust Emission ◽  
Positive Influence ◽  
Dust Particles ◽  
Weather Research And Forecasting ◽  
Western Coast ◽  
Emission Rates ◽  
Dust Deposition ◽  
Santa Ana ◽  
Santa Ana Winds

Numerical simulations revealed a profound interaction between the severe dust storm of 2007 caused by Santa Ana winds and the Gulf of California. The weather research and forecasting model coupled with a chemistry module (WRF-CHEM) and the hybrid single-particle Lagrangian integrated trajectory model (HYSPLIT) allowed for the estimation of the meteorological and dynamic aspects of the event and the dust deposition on the surface waters of the Gulf of California caused by the erosion and entrainment of dust particles from the surrounding desert regions. The dust emission rates from three chosen areas (Altar desert, Sonora coast, and a region between these two zones) and their contribution to dust deposition over the Gulf of California were analyzed. The Altar Desert had the highest dust emission rates and the highest contribution to dust deposition over the Gulf of California, i.e., it has the most critical influence with 96,879 tons of emission and 43,539 tons of dust deposition in the gulf. An increase of chlorophyll-a concentrations is observed coinciding with areas of high dust deposition in the northern and western coast of the gulf. This kind of event could have a significant positive influence over the mineralization and productivity processes in the Gulf of California, despite the soil loss in the eroded regions.

scholarly journals Convective distribution of dust over the Arabian Peninsula: the impact of model resolution

2019 ◽  
Author(s):  
Jennie Bukowski ◽  
Susan C. van den Heever
Keyword(s):  
Arabian Peninsula ◽  
Dust Emission ◽  
Dust Storms ◽  
Radiation Budget ◽  
Grid Spacing ◽  
Heating Rates ◽  
Dust Transport ◽  
Order Of Magnitude ◽  
The Impact ◽  
Cumulus Parameterizations

Abstract. Along the coasts of the Arabian Peninsula, convective dust storms are a considerable source of mineral dust to the atmosphere. Reliable predictions of convective dust events are necessary to determine their effects on air quality, visibility, and the radiation budget. In this study, the Weather Research and Forecasting Model coupled with Chemistry (WRF-Chem) is used to simulate a 2016 summertime dust event over the Arabian Peninsula and examine the variability in dust fields and associated vertical transport due to the choice of convective parameterization and explicit versus parameterized convection. Simulations are run at 45 km and 15 km grid spacing with multiple cumulus parameterizations, and are compared to a 3 km simulation that permits explicit convective processes. Five separate cumulus parameterizations at 15 km grid spacing were tested to quantify the spread across different parameterizations. Finally, the impact these variations have on radiation, specifically aerosol heating rates is also investigated. On average, in these simulations the explicit case produces higher quantities of dust than the parameterized cases in terms of dust uplift potential, vertical dust concentrations, and vertical dust fluxes. Major drivers of this discrepancy between the simulations stem from the explicit case exhibiting higher surface windspeeds during convective activity, lower dust emission wind threshold velocities due to drier soil, and more frequent, stronger vertical velocities which transport dust aloft and increase the atmospheric lifetime of these particles. For aerosol heating rates in the lowest levels, the shortwave effect prevails in the explicit case with a net cooling effect, whereas a longwave net warming effect is present in the parameterized cases. The spread in dust concentrations across cumulus parameterizations at the same grid resolution (15 km) is an order of magnitude lower than the impact of moving from parameterized to explicit convection. We conclude that tuning dust emissions in coarse resolution simulations can only improve the results to first-order and cannot fully rectify the discrepancies originating from disparities in the representation of convective dust transport.

Dust distribution at a coal shearer in the face area

2020 ◽  
pp. 65-73
Author(s):  
A. S. Kobylkin
Keyword(s):  
Air Flow ◽  
Dust Emission ◽  
Sampling Procedure ◽  
Dust Particles ◽  
Dust Deposition ◽  
Particulate Emission ◽  
Face Area ◽  
Laboratory Test Results ◽  
The Face ◽  
Dust Distribution

Compliance with the Federal Code on Safety in Coal Mine, §22, No. 550 as of November 19, 2013 (as edited on January 1, 2020) dictates air dustiness and dust deposition control to be implemented in mines using stationary and mobile facilities. Application procedures of stationary controllers should be science-based and tested to provide reliable information. In particular, the procedures should indicate installation sites for the controllers and dictate revaluation of readings received from the controllers towards the dust explosion prevention in mines. Aimed to develop a framework for such procedures and to revise measurement areas for the movable controllers, dust distribution in roadways was studied. The studies have found out that particulate emission and dust distribution in the face area is complex due to mobility of the source of dust in the coal face area. Characteristics of dust particles govern their behavior in air flow. Thus, it is required to know characteristics of dust particles at the dust emission point to track their travel in roadways. A dust sampling procedure was developed to sample dust at a coal shearer. The data on characteristics of dust particles were also obtained. The mine and laboratory test results were used as the initial and boundary conditions in computational modeling. The mine researches and the modeling show that air flow is split into two parts in longwall. Dust produced by coal cutting by the shearer moves with air flow above the armored face conveyor. These results highlight the importance of taking into account local and head drags when selecting installation sites for controllers of air dust content and dust deposition in coal mines.

Large influence of dust on the Precambrian climate 

2021 ◽  
Author(s):  
Peng Liu ◽  
Yonggang Liu ◽  
Yiran Peng ◽  
Jean-Francois Lamarque ◽  
Mingxing Wang ◽  
...  
Keyword(s):  
Global Climate ◽  
Marine Ecosystem ◽  
Dust Emission ◽  
System Model ◽  
Earth System ◽  
Dust Deposition ◽  
Surface Climate ◽  
Order Of Magnitude ◽  
Dust Loading ◽  
Desert Regions

<p>On present-day Earth, dust emissions are restricted only to a few desert regions mainly due to the distribution of land vegetation. The atmospheric dust loading is thus relatively small and has a slight cooling effect on the surface climate. For the Precambrian (before ~540 Ma), however, dust emission might be much more widespread since land vegetation was absent. Here, our simulations using an Earth system model (CESM1.2.2) demonstrate that the global dust emission during that time might be an order of magnitude larger than that of the present day, and could have cooled the global climate by ~10 °C. Similarly, the dust deposition in the ocean, an important source of nutrition for the marine ecosystem, was also increased by a factor of ~10. Therefore, dust was a critical component of the early Earth system, and should always be considered when studying the climate and biogeochemistry of the Precambrian.</p>

scholarly journals The global dust cycle and uncertainty in CMIP5 (Coupled Model Intercomparison Project phase 5) models

2020 ◽  
Vol 20 (17) ◽  
pp. 10401-10425
Author(s):  
Chenglai Wu ◽  
Zhaohui Lin ◽  
Xiaohong Liu
Keyword(s):  
Wet Deposition ◽  
Climate Models ◽  
Dust Emission ◽  
Coupled Model ◽  
Dust Particles ◽  
Earth System ◽  
Model Intercomparison ◽  
Dust Deposition ◽  
The Earth ◽  
Intercomparison Project

Abstract. The dust cycle is an important component of the Earth system and has been implemented in climate models and Earth system models (ESMs). An assessment of the dust cycle in these models is vital to address their strengths and weaknesses in simulating dust aerosol and its interactions with the Earth system and enhance the future model developments. This study presents a comprehensive evaluation of the global dust cycle in 15 models participating in the fifth phase of the Coupled Model Intercomparison Project (CMIP5). The various models are compared with each other and with an aerosol reanalysis as well as station observations. The results show that the global dust emission in these models varies by a factor of 4–5 for the same size range. The models generally agree with each other and observations in reproducing the “dust belt”, which extends from North Africa, the Middle East, Central and South Asia to East Asia, although they differ greatly in the spatial extent of this dust belt. The models also differ in other dust source regions such as North America and Australia. We suggest that the coupling of dust emission with dynamic vegetation can enlarge the range of simulated dust emission. For the removal process, all the models estimate that wet deposition is smaller than dry deposition and wet deposition accounts for 12 %–39 % of total deposition. The models also estimate that most (77 %–91 %) dust particles are deposited onto continents and 9 %–23 % of dust particles are deposited into oceans. Compared to the observations, most models reproduce the dust deposition and dust concentrations within a factor of 10 at most stations, but larger biases by more than a factor of 10 are also noted at specific regions and for certain models. These results highlight the need for further improvements of the dust cycle especially on dust emission in climate models.

scholarly journals Impacts of dust deposition on dissolved trace metal concentrations (Mn, Al and Fe) during a mesocosm experiment

2013 ◽  
Vol 10 (4) ◽  
pp. 2583-2600 ◽  
Author(s):  
K. Wuttig ◽  
T. Wagener ◽  
M. Bressac ◽  
A. Dammshäuser ◽  
P. Streu ◽  
...  
Keyword(s):  
Trace Metal ◽  
Surface Waters ◽  
Saharan Dust ◽  
Dust Particles ◽  
Dust Deposition ◽  
Crustal Rocks ◽  
Surface Ocean ◽  
Complex Processes ◽  
Order Of Magnitude ◽  
Dust Events

Abstract. The deposition of atmospheric dust is the primary process supplying trace elements abundant in crustal rocks (e.g. Al, Mn and Fe) to the surface ocean. Upon deposition, the residence time in surface waters for each of these elements differs according to their chemical speciation and biological utilization. Presently, however, the chemical and physical processes occurring after atmospheric deposition are poorly constrained, principally because of the difficulty in following natural dust events in situ. In the present work we examined the temporal changes in the biogeochemistry of crustal metals (in particular Al, Mn and Fe) after an artificial dust deposition event. The experiment was contained inside trace metal clean mesocosms (0–12.5 m depths) deployed in the surface waters of the northwestern Mediterranean, close to the coast of Corsica within the frame of the DUNE project (a DUst experiment in a low Nutrient, low chlorophyll Ecosystem). Two consecutive artificial dust deposition events, each mimicking a wet deposition of 10 g m−2 of dust, were performed during the course of this DUNE-2 experiment. The changes in dissolved manganese (Mn), iron (Fe) and aluminum (Al) concentrations were followed immediately after the seeding with dust and over the following week. The Mn, Fe and Al inventories and loss or dissolution rates were determined. The evolution of the inventories after the two consecutive additions of dust showed distinct behaviors for dissolved Mn, Al and Fe. Even though the mixing conditions differed from one seeding to the other, Mn and Al showed clear increases directly after both seedings due to dissolution processes. Three days after the dust additions, Al concentrations decreased as a consequence of scavenging on sinking particles. Al appeared to be highly affected by the concentrations of biogenic particles, with an order of magnitude difference in its loss rates related to the increase of biomass after the addition of dust. In the case of dissolved Fe, it appears that the first dust addition resulted in a decrease as it was scavenged by sinking dust particles, whereas the second seeding induced dissolution of Fe from the dust particles due to the excess Fe binding ligand concentrations present at that time. This difference, which might be related to a change in Fe binding ligand concentration in the mesocosms, highlights the complex processes that control the solubility of Fe. Based on the inventories at the mesocosm scale, the estimations of the fractional solubility of metals from dust particles in seawater were 1.44 ± 0.19% and 0.91 ± 0.83% for Al and 41 ± 9% and 27 ± 19% for Mn for the first and the second dust addition. These values are in good agreement with laboratory-based estimates. For Fe no fractional solubility was obtained after the first seeding, but 0.12 ± 0.03% was estimated after the second seeding. Overall, the trace metal dataset presented here makes a significant contribution to enhancing our knowledge on the processes influencing trace metal release from Saharan dust and the subsequent processes of bio-uptake and scavenging in a low nutrient, low chlorophyll area.

scholarly journals Global dust cycle and uncertainty in CMIP5 models

2020 ◽  
Author(s):  
Chenglai Wu ◽  
Zhaohui Lin ◽  
Xiaohong Liu
Keyword(s):  
Wet Deposition ◽  
Climate Models ◽  
Dust Emission ◽  
Coupled Model ◽  
Dust Particles ◽  
Cmip5 Models ◽  
Earth System ◽  
Dust Deposition ◽  
Total Deposition ◽  
The Earth

Abstract. Dust cycle is an important component of the Earth system and have been implemented into climate models and Earth System Models (ESMs). An assessment of the dust cycle in these models is vital to address the strengths and weaknesses of these models in simulating dust aerosol and its interactions with the Earth system and enhance the future model developments. This study presents a comprehensive evaluation of global dust cycle in 15 models participating in the fifth phase of the Coupled Model Intercomparison Project (CMIP5). The various models are compared with each other and with an aerosol reanalysis as well as station observations of dust deposition and concentrations. The results show that the global dust emission in these models ranges from 735 to 8186 Tg yr−1 and the annual mean dust burden ranges from 2.5 to 41.9 Tg, both of which scatter by a factor of about 10–20. The models generally agree with each other and observations in reproducing the dust belt that extends from North Africa, Middle East, Central and South Asia, to East Asia, although they differ largely in the spatial extent of this dust belt. The models also differ in other dust source regions such as North America and Australia, where the contributions of these sources to global dust emissions vary by a factor of more than 500. We suggest that the coupling of dust emission with dynamic vegetation can enlarge the range of simulated dust emission. For the removal process, all the models estimate that wet deposition is a smaller sink than dry deposition and wet deposition accounts for 12–39 % of total deposition. The models also estimate that most (77–91 %) of dust particles are deposited onto continents and 9–23 % of them are deposited into oceans. A linear relationship between dust burden, lifetime, and fraction of wet deposition to total deposition from these models suggests a general consistency among the models. Compared to the observations, most models reproduce the dust deposition and dust concentrations within a factor of 10 at most stations, but larger biases by more than a factor of 10 are also noted at specific regions and for certain models. These results cast a doubt on the interpretation of the simulations of dust-affected fields in climate models and highlight the need for further improvements of dust cycle especially on dust emission in climate models.

scholarly journals Impacts of dust deposition on dissolved trace metal concentrations (Mn, Al and Fe) during a mesocosm experiment

2012 ◽  
Vol 9 (10) ◽  
pp. 13857-13897 ◽  
Author(s):  
K. Wuttig ◽  
T. Wagener ◽  
M. Bressac ◽  
A. Dammshäuser ◽  
P. Streu ◽  
...  
Keyword(s):  
Trace Metal ◽  
Surface Waters ◽  
Saharan Dust ◽  
Dust Particles ◽  
Dust Deposition ◽  
Crustal Rocks ◽  
Surface Ocean ◽  
Complex Processes ◽  
Order Of Magnitude ◽  
Dust Events

Abstract. The deposition of atmospheric dust is the primary process supplying trace elements abundant in crustal rocks (e.g. Al, Mn and Fe) to the surface ocean. Upon deposition, the residence time in surface waters for each of these elements differs according to their chemical speciation and biological utilization. Presently however their behavior after atmospheric deposition is poorly constrained, principally because of the difficulty in following natural dust events in-situ. In the present work we examined the temporal changes in the biogeochemistry of crustal metals (in particular Al, Mn and Fe) after an artificial dust deposition event. The experiment was contained inside trace metal clean mesocosms (0–12.5 m depths) deployed in the surface waters of the Northwestern Mediterranean, close to the coast of Corsica in the frame of the DUNE project (a DUst experiment in a low Nutrient low chlorophyll Ecosystem). Two consecutive artificial dust deposition events, each mimicking a wet deposition of 10 g m−2 of dust, were performed during the course of this DUNE-2 experiment. The changes in dissolved manganese (dMn), iron (dFe) and aluminium (dAl) concentrations were followed immediately and over the following week and their inventories and loss or dissolution rates were determined. The evolution of the inventories after the two consecutive additions of dust showed distinct behaviors for dMn, dAl and dFe. Even though the mixing conditions differed from one seeding to the other, dMn and dAl showed clear increases directly after both seedings due to dissolution processes. Three days after the dust additions, dAl concentrations decreased as a consequence of scavenging on sinking particles. dAl appeared to be highly affected by the concentrations of biogenic particles, with an order of magnitude difference in its loss rates related to the increase of biomass after the addition of dust. For dFe concentrations, the first dust addition decreased the concentrations through scavenging of the dust particles, whereas the second seeding induced dissolution of Fe from the dust particles. This difference, which might be related to a change in Fe-binding ligand concentration in the mesocosms, highlights the complex processes that control the solubility of Fe. Based on the inventories at the mesocosm scale, the estimations of solubility of metals from dust particles in seawater were 1% for Al and 40% for Mn which were in good agreement with laboratory based estimates. Overall, the trace metal dataset presented here makes a significant contribution to enhancing our knowledge on the processes influencing trace metals release from Saharan dust and the subsequent processes of bio-uptake and scavenging in a low nutrient low chlorophyll area.

scholarly journals Simulation of a severe dust storm with different dust emission schemes

2019 ◽  
Vol 99 ◽  
pp. 02013 ◽  
Author(s):  
Nasim Hossein Hamzeh ◽  
Sara Karami ◽  
Abbas Ranjbar
Keyword(s):  
Middle East ◽  
Land Surface ◽  
Regional Scale ◽  
Dust Emission ◽  
High Sensitivity ◽  
Surface Concentration ◽  
Dust Storms ◽  
Dust Particles ◽  
Dust Transport ◽  
Prediction And Simulation

Dust storms are natural hazards and affect many countries of the world especially the Middle East. So in order to prevent dustdamages, to a certain extent, dust prediction and simulation should be deemed vital. For this purpose, regional-scale simulations are compared in this study, by means of WRF-Chem using five emission schemes. Based on the model outputs, satellite imagery, and backtrajectory analysis, it is shown that the dust particles transfer from Iran into Iraq. Furthermore, over Ilam province (south-west of Iran), the comparison of the surface concentration from different model outputs shows the results depend on the considered dust emission scheme. In general, it can be stated that choosing different dust emission schemes has a significant effect on the output of the model. Shao schemes have high sensitivity to the land surface data and the low resolution of this data in the Middle East causes some errors in dust flux simulation in the region. AFWA and GOCART schemes show more accurate results in the dust transport in the whole area compared to Shao schemes in the presented case study.

scholarly journals Inverting the East Asian Dust Emission Fluxes Using the Ensemble Kalman Smoother and Himawari-8 AODs: A Case Study with WRF-Chem v3.5.1

Atmosphere ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 543
Author(s):  
Dai ◽  
Cheng ◽  
Goto ◽  
Schutgens ◽  
Kikuchi ◽  
...  
Keyword(s):  
Dust Emission ◽  
Asian Dust ◽  
Geostationary Satellite ◽  
Satellite Observations ◽  
Dust Emissions ◽  
Total Dust ◽  
Kalman Smoother ◽  
Independent Observations ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Horizontal And Vertical Distributions

We present the inversions (back-calculations or optimizations) of dust emissions for a severe winter dust event over East Asia in November 2016. The inversion system based on a fixed-lag ensemble Kalman smoother is newly implemented in the Weather Research and Forecasting model and is coupled with Chemistry (WRF-Chem). The assimilated observations are the hourly aerosol optical depths (AODs) from the next-generation geostationary satellite Himawari-8. The posterior total dust emissions (2.59 Tg) for this event are 3.8 times higher than the priori total dust emissions (0.68 Tg) during 25–27 November 2016. The net result is that the simulated aerosol horizontal and vertical distributions are both in better agreement with the assimilated Himawari-8 observations and independent observations from the ground-based AErosol RObotic NETwork (AERONET), the satellite-based Moderate Resolution Imaging Spectroradiometer (MODIS) and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). The developed emission inversion approach, combined with the geostationary satellite observations, can be very helpful for properly estimating the Asian dust emissions.

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