scholarly journals Emission, transport, and radiative effects of mineral dust from the Taklimakan and Gobi deserts: comparison of measurements and model results

2017 ◽  
Vol 17 (3) ◽  
pp. 2401-2421 ◽  
Author(s):  
Siyu Chen ◽  
Jianping Huang ◽  
Litai Kang ◽  
Hao Wang ◽  
Xiaojun Ma ◽  
...  
Keyword(s):  
East Asia ◽  
Dust Emission ◽  
Dust Concentration ◽  
Dust Particles ◽  
Storm Event ◽  
Gobi Desert ◽  
Radiative Effects ◽  
Dust Aerosols ◽  
Budget Analysis ◽  
Westerly Jets

Abstract. The Weather Research and Forecasting Model with chemistry (WRF-Chem model) was used to investigate a typical dust storm event that occurred from 18 to 23 March 2010 and swept across almost all of China, Japan, and Korea. The spatial and temporal variations in dust aerosols and the meteorological conditions over East Asia were well reproduced by the WRF-Chem model. The simulation results were used to further investigate the details of processes related to dust emission, long-range transport, and radiative effects of dust aerosols over the Taklimakan Desert (TD) and Gobi Desert (GD). The results indicated that weather conditions, topography, and surface types in dust source regions may influence dust emission, uplift height, and transport at the regional scale. The GD was located in the warm zone in advance of the cold front in this case. Rapidly warming surface temperatures and cold air advection at high levels caused strong instability in the atmosphere, which strengthened the downward momentum transported from the middle and low troposphere and caused strong surface winds. Moreover, the GD is located in a relatively flat, high-altitude region influenced by the confluence of the northern and southern westerly jets. Therefore, the GD dust particles were easily lofted to 4 km and were the primary contributor to the dust concentration over East Asia. In the dust budget analysis, the dust emission flux over the TD was 27.2 ± 4.1 µg m−2 s−1, which was similar to that over the GD (29 ± 3.6 µg m−2 s−1). However, the transport contribution of the TD dust (up to 0.8 ton d−1) to the dust sink was much smaller than that of the GD dust (up to 3.7 ton d−1) because of the complex terrain and the prevailing wind in the TD. Notably, a small amount of the TD dust (PM2.5 dust concentration of approximately 8.7 µg m−3) was lofted to above 5 km and transported over greater distances under the influence of the westerly jets. Moreover, the direct radiative forcing induced by dust was estimated to be −3 and −7 W m−2 at the top of the atmosphere, −8 and −10 W m−2 at the surface, and +5 and +3 W m−2 in the atmosphere over the TD and GD, respectively. This study provides confidence for further understanding the climate effects of the GD dust.

scholarly journals Emission, transport and radiative effects of mineral dust from Taklimakan and Gobi Deserts: comparison of measurements and model results

2016 ◽  
Author(s):  
Siyu Chen ◽  
Jianping Huang ◽  
Litai Kang ◽  
Hao Wang ◽  
Xiaojun Ma ◽  
...  
Keyword(s):  
East Asia ◽  
Dust Emission ◽  
Dust Concentration ◽  
Dust Particles ◽  
Storm Event ◽  
Gobi Desert ◽  
Radiative Effects ◽  
Climate Effect ◽  
Dust Aerosols ◽  
Westerly Jets

Abstract. The weather research and forecasting model with chemistry (WRF-Chem) was used to investigate a typical dust storm event that occurred from 18th to 23rd March 2010 and swept across almost all of China, Japan, and Korea. WRF-Chem captured the spatial and temporal variations in dust aerosols and the meteorological conditions over East Asia well, and the results were used to further investigate details of processes related to dust emission, long-range transport, and radiative effects of dust aerosols over the Taklimakan desert (TD) and Gobi desert (GD). Results showed that the differences of weather conditions and topography and surface types in dust source regions may lead to the differences of dust emission, uplift height and transport. The typical dust event over East Asia was classified into two main stages. In the first stage (18th–20th March), the GD was located in the warm zone in advance of a cold front. The enhanced convection increased momentum transfer in the middle and lower troposphere because of the instability in the atmosphere. Moreover, the GD is located in relatively flat, high altitude regions influenced by the confluence of the northern and southern westerly jets. Therefore, the GD dust transport was the primary contributor to the dust concentration over East Asia. The strength of the dust emission decreased greatly during the second stage (21st–23rd March). The TD dust emission contributed to the dust concentration over East Asia. Cold air was lifted over the Pamir Plateau and intruded into the Tarim basin causing a strong uplifting motion. The average TD dust emission flux was 27.2 ± 4.1 μg m−2 s−1. However, the transport contribution of the TD dust (1.1 ton day−1) to the dust sink was smaller than that of the GD dust (1.4 ton day−1) because of the complex terrain and the prevailing wind in the TD. It is noted that the TD is not the main source region in China but a small amount of the TD dust was lofted to more than 5 km and transported over greater distances under the influence of the westerly jets. Moreover, the radiative forcing induced by dust particles is estimated as −3 W m−2 and −7 W m−2 at the top of the atmosphere, −8 W m−2 and −10 W m−2 at the surface, and +5 W m−2 and +3 W m−2 in the atmosphere over the TD and GD, respectively. The study provided confidence for further understanding the climate effect of the TD and GD dust.

scholarly journals Simulation and Analyses of the Potential Impacts of Different Particle-Size Dust Aerosols Caused by the Qinghai-Tibet Plateau Desertification on East Asia

2020 ◽  
Vol 12 (8) ◽  
pp. 3231
Author(s):  
Jie Xiong ◽  
Tianliang Zhao ◽  
Yongqing Bai ◽  
Yu Liu ◽  
Yongxiang Han
Keyword(s):  
East Asia ◽  
Circulation Model ◽  
Tibet Plateau ◽  
Dust Particles ◽  
Large Contribution ◽  
Dust Aerosols ◽  
Model Community ◽  
High Concentrations ◽  
Global Atmospheric Circulation ◽  
Qinghai Tibet Plateau

In this paper on the analysis of the vertical distribution of different-diameter dust aerosols and the potential impacts on East Asia, the sensitivity simulation tests of dust aerosols during 2002–03 were conducted by changing the underlying surface on the Qinghai-Tibet Plateau in the global atmospheric circulation model Community Atmosphere Model (CAM) 3.1. The results show that dust aerosol particles in East Asia are mainly distributed in the diameters of 0.64–5.12 μm. The high concentrations of dust aerosols are centered on the surface in the source areas and gradually raised during the eastward transport across East Asia, reaching a height of 4 km at 120° E. The small dust particles with diameters less than 1.28 μm are transported higher and farther driven by the midlatitude westerlies. The Qinghai-Tibet Plateau desertification leads to increasing concentrations of dust aerosols in all size bins and raisesthe transport height of dust aerosols in East Asia. The long-range transport in the East Asian troposphere is dominated by dust aerosols particles of diameters 0.64–2.56 μm, as well as a large contribution of dust aerosols with diameters larger than 1.28 μm.

scholarly journals Can MERRA-2 Reanalysis Data Reproduce the Three-Dimensional Evolution Characteristics of a Typical Dust Process in East Asia? A Case Study of the Dust Event in May 2017

2020 ◽  
Vol 12 (6) ◽  
pp. 902 ◽  
Author(s):  
Wenrui Yao ◽  
Huizheng Che ◽  
Ke Gui ◽  
Yaqiang Wang ◽  
Xiaoye Zhang
Keyword(s):  
East Asia ◽  
Dust Emission ◽  
Three Dimensional ◽  
Vertical Motion ◽  
Source Area ◽  
Northwest China ◽  
Storm Event ◽  
Dust Event ◽  
Long Distance ◽  
Reanalysis Dataset

This study used the MERRA-2 reanalysis dataset and ground-based and satellite observational data to comprehensively analyze a typical dust storm event in east Asia on 2–7 May 2017 which engulfed most of China as well as ocean and Japan, and explore the accuracy and comprehensiveness of the MERRA-2 dataset in the analysis of dust processes. The results of comparison show that the description of the spatiotemporal distribution and evolution of the dust aerosols in the dust event using the MERRA-2 data is consistent with the data of AERONET, National Urban Air Quality Real-time Publishing Platform and Hamawari-8. Gobi Deserts was the most influential source area of this dust event with the highest emissions reaching 1.9 × 106 μg/m3. The vertical motion of the atmosphere can lift dust from the source area above 500 hPa. There were low-pressure troughs at 500 and 850 hPa and the winds behind and in front of the trough led to the high-altitude, long-distance transport of dust. Dust gradually affected the northwest China, north China, northeast China, and even the ocean and Japan on 2–7 May. This study demonstrates that although there is some uncertainty about the source of dust emission in the MERRA-2 model, the data accurately simulated the evolution of the dust event and analyze it comprehensively, while the accuracy of simulating the long-term evolution of dust requires further evaluation.

scholarly journals Vertical Structures of Dust Aerosols over East Asia Based on CALIPSO Retrievals

2019 ◽  
Vol 11 (6) ◽  
pp. 701 ◽  
Author(s):  
Di Liu ◽  
Tianliang Zhao ◽  
Richard Boiyo ◽  
Siyu Chen ◽  
Zhengqi Lu ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
East Asia ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Dust Particles ◽  
Dust Source ◽  
Layer Height ◽  
Dust Aerosols ◽  
Source Regions ◽  
Autumn And Winter

The spatiotemporal and especially the vertical distributions of dust aerosols play crucial roles in the climatic effect of dust aerosol. In the present study, the spatial-temporal distribution of dust aerosols over East Asia was investigated using Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) retrievals (01/2007–12/2011) from the perspective of the frequency of dust occurrence (FDO), dust top layer height (TH) and profile of aerosol subtypes. The results showed that a typical dust belt was generated from the dust source regions (the Taklimakan and Gobi Deserts), in the latitude range of 25°N~45°N and reaching eastern China, Japan and Korea and, eventually, the Pacific Ocean. High dust frequencies were found over the dust source regions, with a seasonal sequence from high to low as follows: spring, summer, autumn and winter. Vertically, FDOs peaked at about 2 km over the dust source regions. In contrast, FDOs decreased with altitude over the downwind regions. On the dust belt from dust source regions to downwind regions, the dust top height (TH) was getting higher and higher. The dust TH varied in the range of 1.9–3.1 km above surface elevation (a.s.e.), with high values over the dust source regions and low values in the downwind areas, and a seasonally descending sequence of summer, spring, autumn and winter in accord with the seasonal variation of the boundary layer height. The annual AOD (Aerosol Optical Depth) was generally characterized by two high and two low AOD centers over East Asia. The percent contribution of the Dust Aerosol Optical Depth to the total AOD showed a seasonal variation from high to low as follows: spring, winter, autumn and summer. The vertical profile of the extinction coefficient revealed the predominance of pure dust particles in the dust source regions and a mixture of dust particles and pollutants in the downwind regions. The dust extinction coefficients over the Taklimakan Desert had a seasonal pattern from high to low as follows: spring, winter, summer and autumn. The results of the present study offered an understanding of the horizontal and vertical structures of dust aerosols over East Asia and can be used to evaluate the performance aerosol transport models.

scholarly journals Dust aerosol radiative effects during summer 2012 simulated with a coupled regional aerosol–atmosphere–ocean model over the Mediterranean

2015 ◽  
Vol 15 (6) ◽  
pp. 3303-3326 ◽  
Author(s):  
P. Nabat ◽  
S. Somot ◽  
M. Mallet ◽  
M. Michou ◽  
F. Sevault ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Mediterranean Region ◽  
Short Wave ◽  
Ocean Model ◽  
Dust Particles ◽  
Radiative Effects ◽  
Aerosol Radiative Forcing ◽  
Dust Aerosols ◽  
The Mediterranean ◽  
Aerosol Radiative

Abstract. The present study investigates the radiative effects of dust aerosols in the Mediterranean region during summer 2012 using a coupled regional aerosol–atmosphere–ocean model (CNRM-RCSM5). A prognostic aerosol scheme, including desert dust, sea salt, organic, black-carbon and sulphate particles, has been integrated to CNRM-RCSM5 in addition to the atmosphere, land surface and ocean components. An evaluation of this aerosol scheme of CNRM-RCSM5, and especially of the dust aerosols, has been performed against in situ and satellite measurements, showing its ability to reproduce the spatial and temporal variability of aerosol optical depth (AOD) over the Mediterranean region in summer 2012. The dust vertical and size distributions have also been evaluated against observations from the TRAQA/ChArMEx campaign. Three simulations have been carried out for summer 2012 with CNRM-RCSM5, including the full prognostic aerosol scheme, only monthly-averaged AOD means from the aerosol scheme or no aerosols at all, in order to focus on the radiative effects of dust particles and the role of the prognostic scheme. Surface short-wave aerosol radiative forcing variability is found to be more than twice as high over regions affected by dust aerosols, when using a prognostic aerosol scheme instead of monthly AOD means. In this case downward surface solar radiation is also found to be better reproduced according to a comparison with several stations across the Mediterranean. A composite study over 14 stations across the Mediterranean, designed to identify days with high dust AOD, also reveals the improvement of the representation of surface temperature brought by the use of the prognostic aerosol scheme. Indeed the surface receives less radiation during dusty days, but only the simulation using the prognostic aerosol scheme is found to reproduce the observed intensity of the dimming and warming on dusty days. Moreover, the radiation and temperature averages over summer 2012 are also modified by the use of prognostic aerosols, mainly because of the differences brought in short-wave aerosol radiative forcing variability. Therefore this first comparison over summer 2012 highlights the importance of the choice of the representation of aerosols in climate models.

scholarly journals Size-segregated fluxes of mineral dust from a desert area of northern China by eddy covariance

2007 ◽  
Vol 7 (1) ◽  
pp. 2133-2168
Author(s):  
G. Fratini ◽  
P. Ciccioli ◽  
A. Febo ◽  
A. Forgione ◽  
R. Valentini
Keyword(s):  
Eddy Covariance ◽  
Mineral Dust ◽  
Northern China ◽  
Dust Particles ◽  
Storm Event ◽  
Gobi Desert ◽  
Storm Events ◽  
Particle Volume ◽  
Intense Storm ◽  
Desert Areas

Abstract. Mineral dust emission accounts for a substantial portion of particles present in the troposphere. It is emitted most from desert areas, mainly through intense storm episodes. The aim of this work was to quantify size-segregated fluxes of mineral dust particles emitted during storm events occurring in desert areas of northern China (Alashan desert, Inner Mongolia), known to act as one of the strongest sources of mineral dust particles in the Asian continent. Long-range transport of mineral dust emitted in this area is responsible for the high particle concentrations reached in densely populated areas, including the city of Beijing. Based on a theoretical analysis, an eddy covariance system was built to get size-segregated fluxes of mineral dust particles with optical diameters ranging between 0.26 and 7.00 μm. The system was optimised to measure fluxes under intense storm event conditions. It was tested in two sites located in the Chinese portion of the Gobi desert. During the field campaign, an intense storm event was recorded in one of them. Data obtained during this event indicate that particle number fluxes were dominated by the finer fraction, whereas in terms of volume, coarser particle accounted for the largest portion. It was found that during the storm event, ratios of size-segregated particle volume fluxes remained substantially constant and a simple parameterization of particle emission from total volume fluxes was possible. A strong correlation was also found between particle volume fluxes and the friction velocity. This relationship is extremely useful to investigate mechanisms of particle formation by wind erosion.

scholarly journals Model development of dust emission and heterogeneous chemistry within the Community Multiscale Air Quality modeling system and its application over East Asia

2015 ◽  
Vol 15 (24) ◽  
pp. 35591-35643 ◽  
Author(s):  
X. Dong ◽  
J. S. Fu ◽  
K. Huang ◽  
D. Tong
Keyword(s):  
Soil Moisture ◽  
Air Quality ◽  
East Asia ◽  
Model Development ◽  
Dust Emission ◽  
Temporal Variations ◽  
Heterogeneous Chemistry ◽  
Dust Aerosols ◽  
Meteorological Simulation ◽  
The Impact

Abstract. The Community Multiscale Air Quality (CMAQ) model has been further developed in terms of simulating natural wind-blown dust in this study, with a series of modifications aimed at improving the model's capability to predict the emission, transport, and chemical reactions of dust aerosols. The default parameterization of threshold friction velocity constants in the CMAQ are revised to avoid double counting of the impact of soil moisture based on the re-analysis of field experiment data; source-dependent speciation profiles for dust emission are derived based on local measurements for the Gobi and Taklamakan deserts in East Asia; and dust heterogeneous chemistry is implemented to simulate the reactions involving dust aerosol. The improved dust module in the CMAQ was applied over East Asia for March and April from 2006 to 2010. Evaluation against observations has demonstrated that simulation bias of PM10 and aerosol optical depth (AOD) is reduced from −55.42 and −31.97 % in the original CMAQ to −16.05 and −22.1 % in the revised CMAQ, respectively. Comparison with observations at the nearby Gobi stations of Duolun and Yulin indicates that applying a source-dependent profile helps reduce simulation bias for trace metals. Implementing heterogeneous chemistry is also found to result in better agreement with observations for sulfur dioxide (SO2), sulfate (SO42-), nitric acid (HNO3), nitrous oxides (NOx), and nitrate (NO3-). Investigation of a severe dust storm episode from 19 to 21 March 2010 suggests that the revised CMAQ is capable of capturing the spatial distribution and temporal variations of dust aerosols. Model evaluation indicates potential uncertainties within the excessive soil moisture fraction used by meteorological simulation. The mass contribution of fine mode aerosol in dust emission may be underestimated by 50 %. The revised revised CMAQ provides a useful tool for future studies to investigate the emission, transport, and impact of wind-blown dust over East Asia and elsewhere.

scholarly journals Simulation of an Asian Dust Storm Event in May 2017

Atmosphere ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 135 ◽  
Author(s):  
Ping Song ◽  
Jianfang Fei ◽  
Changshun Li ◽  
Xiaogang Huang
Keyword(s):  
Size Distribution ◽  
Dust Storm ◽  
Source Region ◽  
Dust Emission ◽  
Northern China ◽  
Dust Particles ◽  
Storm Event ◽  
Dust Size Distribution ◽  
Dust Storm Event ◽  
Local Dust

Dust particles in the atmosphere play an important role in air pollution, climate change, and biogeochemical cycles. Some of the dominant sources of dust in mid-latitude regions are in Asia. An intense dust storm engulfed Northern China at the beginning of May 2017, and PM10 mass concentrations of 1500–2000 μg m−3 were measured near the dust source region. We combined numerical simulations, air quality monitoring data, and satellite retrievals to investigate dust emission and transport during this event. We found that the event was closely related to cold front activity, characterized by increased wind speed, which increased dust emission. We improved the dust scheme using a local dust size distribution to better simulate the dust emission flux. We found that accurate parametrization of the dust size distribution was important to effectively simulate both dust emission and ambient particle concentration. We showed that using a local dust size distribution substantially improved the accuracy of the simulation, allowing both the spatial distribution of pollution caused by the dust storm and temporal variability in the pollution to be captured.

scholarly journals ANALITIC INVESTIGATION OF THE REGULARITIES OF CHANGING DUST CONCENTRATION DURING THE ABRASIVE DECREASE OF STONE STRUCTURES

2018 ◽  
Vol 2 ◽  
pp. 28-39
Author(s):  
Alla Bezpalova ◽  
Vladimir Lebedev ◽  
Yuri Morozov
Keyword(s):  
Sedimentation Rate ◽  
Cubic Boron Nitride ◽  
Dust Emission ◽  
Building Stone ◽  
Dust Concentration ◽  
Dust Particles ◽  
Building Structures ◽  
High Concentration ◽  
Operating Cycle ◽  
Stone Materials

In the process of repair or restoration of building structures, it is often necessary to strengthen building structures from limestone-shell rock, concrete, reinforced concrete, hard materials-granite, basalt, etc. by cutting or making cuts of the required size with detachable circles of synthetic diamond and cubic boron nitride (CA and CBN) The cutting process is accompanied by considerable dust formation, which can be both harmful and dangerous factor in the work. The aim of the work is studying the process of dust sedimentation and the regularity of the change in dust concentration during the abrasive cutting of concrete and stone materials. Mathematical models have been developed – dust emission from under the wheel, speed of sedimentation of dust particles depending on their material, size and shape, and also depending on temperature, pressure and humidity, the concentration of dust in the working space and the concentration change during the cutting cycle are calculated. It is shown that the velocity of the sedimentation of particles depends significantly on the shape. The higher the sphericity, the higher the sedimentation rate. The ambient temperature has little effect on the sedimentation rate, in the temperature range (-20 → + 40 °C) at which the operation takes place. The sedimentation rate of dust particles generated by cutting the most common building stone materials also differs slightly. Almost the same sedimentation rate has dust particles obtained by cutting basalt and concrete. A bit higher is the sedimentation rate of particles from granite. The sedimentation rate of particles of generated dust is about 600-700 cm/h or 10-11 cm/min for particles measuring 6 μm. This means that at a production height of about 2 m (200 cm) during the operating cycle (about 3 min), the dust will remain at an altitude of about 1.5 m, i.е. practically remains in the working area. This gives grounds to assert about a high concentration of dust during the cutting cycle (about 4.8 108/m3).

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