尺度适应性起沙机制在CMA-CUACE/Dust中的应用

沙尘暴是影响我国重要的灾害性天气之一,针对中国气象局亚洲沙尘暴数值预报系统CMA-CUACE/Dust(China Meteorological Administration Unified Atmospheric Environment for Dust)的沙尘质量浓度在中亚高估、蒙古北部低估、在我国消散过快以及极端沙尘暴预报峰值偏低等问题,应用与模式格距匹配的尺度适应性起沙机制并更新风蚀资料库对模式进行改进。对2021年3月13—17日东亚最强沙尘暴个例和2023年3—5月与业务运行环境一致的连续预报试验表明,改进后的模式(CMA-CUACE/Dust V1.5)有效改善了上述不足,极端沙尘暴过程传输至我国后的沙尘质量浓度峰值与观测接近。连续预报试验TS(threat score)评分显示:CMA-CUACE/Dust V1.5预报一致性和连续性较好,1~5 d不同时效预报TS评分明显高于改进前和韩国模式ADAM(the Asian Dust Aerosol Model),漏报率明显降低,对2023年5次沙尘过程的4次预报TS评分高于0.3,部分过程超过0.5。

Relationship between sand-dust weather and water dynamics of desert areas in the middle reaches of Heihe River

Sand-dust weather has become an international social-environmental issue of common concern, and constitutes a serious threat to human lives and economic development. In order to explore the responses of natural desert sand and dust to the dynamics of water in desertification, we extracted long-term monitoring data related to precipitation, soil water, groundwater, and sand-dust weather. These data originated from the test stations for desertification control in desert areas of the middle reaches of the Heihe River. We used an algorithm of characteristic parameters, correlations, and multiple regression analysis to establish a regression model for the duration of sand-dust weather. The response char-acteristics of the natural desert sand and dust and changes of the water inter-annual and annual variance were also examined. Our results showed： （1） From 2006 to 2014 the frequency, duration, and volatility trends of sand-dust weather obviously increased, but the change amplitudes of precipitation, soil water, and groundwater level grew smaller. （2） In the vegetative growth seasons from March to November, the annual variance rates of the soil moisture content in each of four studied layers of soil samples were similar, and the changes in the frequency and duration of sand-dust weather were similar. （3） Our new regression equation for the duration of sand-dust weather passed the R test, F test, and t test. By this regression model we could predict the duration of sand-dust weather with an accuracy of 42.9%. This study can thus provide technological support and reference data for water resource management and re-search regarding sand-dust weather mechanisms.

Comparison between the Causes and Transmission Characteristics of Two Sand and Dust Weather Processes with Heavy Pollution in Ulanqab City

The actual situation of two sand and dust weather processes with heavy pollution in Ulanqab City in 2021 was analyzed from the aspects of air quality,visibility,PM_(2.5)and PM_(10),and the causes of the sand and dust weather with heavy pollution were discussed.The differences between the two processes in transport characteristics of sand and dust were studied,and the roles of high-and low-altitude weather systems and their impact on sand and dust transport were explored.

The Variation Characteristics of Wind Speed Profile and PM_(10) during Typical Sand Weather in Inner Mongolia,China

Based on the data of the wind speed from 20 m meteorological tower and PM10 mass concentration in Zhurihe region from January of 2005 to April of 2006,the evolution characteristics of wind speed profile in near surface layer and PM10 in three representative dust weather processes (dust storm,blowing sand and floating dust) were analyzed.The results showed that wind speed was higher during dust storm and blowing sand with remarkable vertical gradient.The speed in floating dust was relatively lower and increased during the whole process.In general,wind speed after dust weather was smaller with respect to that before the event.The average mass concentrations of PM10 in the processes of dust storm,blowing sand and floating dust were in the ranges of 5 436.38-10 000,1 799.49-4 006.06 and 1 765.53 μg/m3,respectively.

Identification of sand and dust storm source areas in Iran

Sand and dust storms （SDS） are common phenomena in arid and semi-arid areas. In recent years, SDS frequencies and intensities have increased significantly in Iran. A research on SDS sources is important for understanding the mechanisms of dust generation and assessing its socio-economic and environmental impacts. In this paper, we developed a new approach to identify SDS source areas in Iran using a combination of nine related datasets, namely drought events, temperature, precipitation, location of sandy soils, SDS frequency, hu- man-induced soil degradation （HISD）, human influence index （HII）, rain use efficiency （RUE） and net primary pro- ductivity （NPP） loss. To identify SDS source areas, we firstly normalized these datasets under uniform criteria in- cluding layer reprojection using Lambert conformal conic projection, data conversion from shapefile to raster, Min-Max Normalization with data range from 0 to 1, and data interpolation by Kriging and images resampling （resolution of 1 km）. After that, a score map for the possibility of SDS sources was generated through overlaying multiple datasets under average weight allocation criterion, in which each item obtained weight equally. In the score map, the higher the score, the more possible a specific area could be regarded as SDS source area. Exceptions mostly came from large cities, like Tehran and Isfahan. As a result, final SDS source areas were mapped out, and Al-Howizeh/Al-Azim marshes and Sistan Basin were identified as main SDS source areas in Iran. The SDS source area in Al-Howizeh/Al-Azim marshes still keeps expanding. In addition, Al-Howizeh/Al-Azim marshes are now suf- fering rapid land degradation due to natural and human-induced factors and might totally vanish in the near future. Sistan Basin also demonstrates the impacts of soil degradation and wind erosion. With appropriate intensity, dura- tion, wind speed and altitude of the dust storms, sand particles uplifting from this area might have developed into extreme dust storms, especially during the summer.

Relationship between East Asian Monsoon and Dust Weather Frequency over Beijing

The relationship between dust weather frequency （DWF）, which denotes the number of days of dust weather events, over Beijing and the East Asian Monsoon （EAM） was studied using DWF data for Beijing during the period 1951-2006. Results show that, during this period, the blowing-dust weather frequency （BDWF）, as well as the indices of East Asian winter monsoon （EAWM） and East Asian summer monsoon （EASM）, all decreased considerably, with a t-test confidence level of 99%. The correlation coeffcients between the chosen EAWM index and BDWF over Beijing in winter and the following spring were 0.34 and 0.33, respectively, with significance levels of 0.01 and 0.02, respectively. For the chosen EASM index and BDWF, these correlation coeffcients were 0.51 and 0.45, respectively, with both at a confidence level exceeding 99.9%. With the linear trends removed, the values （in the same order as above） were 0.14, 0.14, -0.12, and -0.09, all not significant at the 95% confidence level. Clearly, the EAM relates mainly to DWF over long timescales. To a certain extent, the EAM might have some impact on DWF by affecting the associated surface air temperature and precipitation during the corresponding time period in sand-dust source regions at the interannual scale. A stronger （weaker） EAWM might advance （suppress） the occurrence of DWF, and the opposite for the EASM.

Two different periods of high dust weather frequency in northern China

This study reveals that, during the period 1966-2014, dust weather frequency （DWF） in northern China （north of 30°N） features two high-DWF periods, in 1966-1979 （PI） and 2000-2014 （P2）, when the linear trend of DWF is removed during the study period. Here, DWF denotes the number of days of dust weather events in the spring season （March-April-May）, including dust haze, blowing dust, and dust storms, which occurred in northern China. The results show that the DWF is much higher in PI than in P2, with increased DWF distributed over southern Xinjiang, the central part of northern China. The main cause is the SST difference in the Atlantic and Pacific between the two periods. It is also found that a meridional teleconnection over East Asia in PI and a zonal wave-like pattern over Eurasia in P2 at 200 hPa play a significant role in the interannual variability in the two periods, respectively. SST over the subtropical North Atlantic （extratropical SST between the Norwegian and Barents seas） may partly contribute to the upper-level meridional （zonal） teleconnection in PI （P2）.

Abrasive Wear Map of Polymer Tapes in Sand Dust Environment

To make clear the wear conditions of ATM (Automatic Teller Machine) tribosystem when servicing in Chi- nese sand dust environment, abrasive wear of two kinds of polymer tapes specified for ATM, PI (Polyimide) and PEN (Polyethylene-2, 6-naphthalenedicarboxylate), was investigated in simulated sand dust environment with ATM tape-scraper tribosystem under various conditions of loads and sliding distances. The surface profiles of worn tape were measured with a surface profiler in order to calculating the wear cross-section areas and the wear volumes. The specific wear rates of polymer tapes were calculated under load conditions of 0.6, 1 and 1.5 N, and wear mechanisms were in- vestigated with optical topography photos. As main results, the specific wear rates show stage variations in the wear process and the wear resistance of polymer tape shows good relationship with the mechanical deformation factors. In consideration of the service life, four wear models are generalized according to the magnitude of specific wear rates, which include no wear, mild wear, normal wear and severe wear model and the corresponding wear mechanisms for the four wear models are discussed with typical worn topographies. Based on the wear models and corresponding wear mechanisms, the abrasive wear maps of two polymer tapes servicing in sand dust environments are concluded for its industrial applications.

Influence of Dust Weather on Air Quality in Lanzhou City

[Objective] The study aimed to discuss the effects of dust weather on air quality in Lanzhou City. [Met]hod] Under the influence of a strong sandstorm during March 8 -15, 2013 on air quality in Gansu Province, the changes of wind speed, atmospheric visibility and PM10 concentra- tion as well as air pollution in Lanzhou were analyzed. [ Result] The dust weather during March 8 -15, 2013 affected Lanzhou City for the longest time in recent 10 years, and the city suffered medium pollution on March 8 and heavy pollution during March 9 -15 under the influence of the dust weather, while PM10 was the pdmary pollutant. [ Condusion] The research could provide the corresponding technical support for the prevention and control of environmental pollution in Lanzhou City.

Sand-dust storms in China: temporal-spatial distribution and tracks of source lands

Sand-dust storm is a special natural disaster that frequently occurs in deserts and their surrounding areas. With the data published onSurface Meteorological Monthly Bulletin andSurface Chart during 1971–1996, the temporal-spatial distribution and annual variation of sand-dust storms are analyzed on the basis of the case study of atmospheric processes. Furthermore, the tracks and source areas of sand-dust storms are determined with the aid of GIS. The results show that except some parts of Qinghai Province and Inner Mongolia as well as Beijing, sand-dust storms decrease apparently in time and space in recent decades in China. Sand-dust storms occur most frequently in spring, especially in April. According to their source areas, sand-dust storms are classified into two types, i.e., the inner-source and outer-source sand-dust storms. Most of the outer-source sand-dust storms move along the north and west tracks. The north-track outer-source sand-dust storms always intrude into China across the Sino-Mongolian border from Hami, a city in the eastern part ofXinjiang, to Xilin Gol, a league in Inner Mongolia, while the west-track ones intrude into China from both southern and northern Xinjiang. The source lands of inner-source sand-dust storms concentrate in the Taklimakan Desert and its surrounding areas in southern Xinjiang, southern part of the Junggar Basin in north of Xinjiang, the Hexi Corridor in western Gansu Province, the dry deserts of Inner Mongolia and the Qaidam Basin in Qinghai.

The influence of different underlying surface on sand-duststorm in northern China

In this paper, a quantitative research on the relationship between different underlying surface and sand-dust storm has been made by using 40 years meteorological data of five different types of underlying surface in northern China, which include farmland, grassland, sandland, gobi and salt crust. These metrological data comprise sand-dust storm days and strong wind days. By analyzing, we can find that there are certain correlations between the days of sand-dust storm and strong wind for different underlying surface, which has great influence on sand-dust storm. But there are pronounced differences in different types of underlying surface. The sand-dust storm days of grassland, gobi and salt crust, with smaller interannual variation are obviously less than strong wind days. On the other hand, the sand-dust storm days of farmland and sandland increase evidently, even in many years, are much more than strong wind days. The differences are mainly induced by the influencing mechanism of different underlying surface on sand-dust storm. Grassland, gobi and salt crust with stable underlying surface are not prone to sand-dust storm under strong wind condition. Whereas, the underlying surface of farmland and sandland is unstable, that is easy to induce sand-dust storm under strong wind condition.

Research on the different content of weathered sand influence on expansive characteristic of a highway expansive soil in Yichang

This paper aims at widespread presence of expansive soil which can be obtained in the project from Xiaoxita to Yaqueling first-class highway rebuilding engineering in Yichang City of Hubei Province and weathered sand which can be made full use locally,many experiments have been made. Compaction experiments and expansibility index indoor experiments of undisturbed expansive soil and expansive soil mixed with sand ranging from 10 % to 50 % have been made. Through the test mixing undisturbed expansive soil with different content of weathered sand,it can change the expansive soil water characteristics and compaction characteristics. It can influence the expansibility of the expansive soil index and significantly inhibit the expansibility of the expansive soil and reach the standard of roadbed filler.

Chemical characteristics of precipitation and the indicative significance for sand dust events in the northern and southern slopes of Wushaoling Mountain, northwestern China

Precipitation chemistry analysis is essential to evaluate the atmospheric environmental quality and identify the sources of atmospheric pollutants. In this study, we collected a total of 480 precipitation samples at 6 sampling sites in the northern and southern slopes of Wushaoling Mountain from May 2013 to July 2014 to analyze the chemical characteristics of precipitation and to identify the main sources of ions in precipitation. Furthermore, we also explored the indicative significance for sand dust events in the northern and southern slopes of Wushaoling Mountain based on the precipitation chemistry analysis.During the sampling period（from May 2013 to July 2014）, the p H values, EC（electrical conductivity）values and concentrations of cations（Ca^（2＋）, Mg^（2＋）, Na~＋, K~＋ and NH_4~＋） and anions（SO_4^（2–）, NO_3~–, Cl~–, NO_2~– and F~–） in precipitation were different in the northern and southern slopes at daily and seasonal time scales, with most of the values being higher in the northern slope than in the southern slope. The chemical type of precipitation in the southern and northern slopes was the same, i.e.,SO_4^（2–）-Ca^（2＋）-NO_3~–-Na~＋. The concentrations of ions in precipitation were mainly controlled by terrigenous material and anthropogenic activities（with an exception of Cl~–）. The concentration of Cl~– in precipitation was mainly controlled by the sea salt fraction. The concentrations of Na＋ and Cl~– showed an increasing trend after the occurrence of sand dust events both in the northern and southern slopes. In addition, after the occurrence of sand dust events, the concentrations of K~＋, Mg^（2＋）, SO_4^（2–）, NO_3~– and Ca^（2＋） showed an increasing trend in the southern slope and a decreasing trend in the northern slope. It is our hope that the results may be helpful to further understand the atmospheric pollution caused by sand dust events in the Wushaoling Mountain and can also provide a scientific basis for the effective prevention of atmospheric pollution.

The atmospheric circulation patterns influencing the frequency of spring sand-dust storms in the Tarim Basin

Using NCEP/NCAR reanalysis data and the sand-storm frequency data fi＇om 37 weather stations in the Tarim Basin for the period 1961-2009, the relationship between the frequency of spring sandstorms in the Tafim Basin and the associated atmospheric circu- lation pattems is analyzed in this study. We found significantly negative correlations between sandstorm frequency and the 500-hPa geopotential height over the Paris Basin and midwestem Mongolia, while there were positive correlations over the Ural River region. The rising of the 500-hPa geopotential height in midwestem Mongolia and its falling over the Ural region corre- spond to a weakening of the large-scale wave patterns in the Eurasian region, which directly causes the frequency of the sand-dust storms in the Tarim Basin to decline. Also, the abrupt decline in the spring sandstorm frequency in the Tarim Basin observed in the last half-century is associated with profound changes in the atmospheric circulation in these key regions. At the interannual scale, the strengthened cyclonic atmospheric circulation patterns in the western part of Mongolia and the anticyclonic patterns over the East European plains at 500-hPa geopotential height, are responsible for frequent sandstorm occurrences in the Tarim Basin.

Investigations of physicochemical properties of dusts generated in mechanical reclamation process of spent moulding sands with alkaline resins

Mechanical reclamation processes of spent moulding sands generate large amounts of postreclamation dusts mainly containing rubbed spent binding agents and quartz dusts. The amount of postreclamation dusts, depending in the reclamation system effi ciency and the reclaim dedusting system, can reach 5%-10% in relation to the total reclaimed spent moulding sand. The proper utilization of such material is a big problem facing foundries these days. This study presents the results of investigations of physicochemical properties of post- reclamation dusts. All tested dusts originated from various Polish cast steel plants applying the mechanical reclamation process of moulding sands with alkaline resins, obtained from different producers. Different dusts, delivered from foundries, were tested to determine their chemical composition, granular characterization, physicochemical and energetic properties. Presented results confi rmed assumptions that it is possible to utilize dusts generated during mechanical reclamation of used sands with organic resins as a source of energy.

Research on Performance of U Separator in Sand and Dust Test System

Sand/dust test is one of the key projects to examine the environmental adaptability of ordnance equipment.In order to decrease the abrasion of test facility caused by the sand/dust particles,the particles contained in the airflowneed to be reclaimed effectively.Amathematical model of Useparator is established.The flowfield and the trajectories of particles inside the separator are obtained using a numerical simulation method,and the separation efficiency and pressure drop of separator with different rows of separate components are also obtained at various flowvelocities.The simulation results indicate that the efficiency of U inertia separator is affected by the flowvelocity evidently,and a reasonably designed separator can meet the requirement of the separation efficiency in particular situation.The results can be use as reference for the design and test of sand/dust separate systems.

Impact of Dust Weather on Air Quality and Solar Radiation

Based on the observation data of PM 10 mass concentration, ground meteorological elements and solar radiation in Dunhuang and Jiuquan , the changing trends of PM 10 mass concentration and solar total radiation in the west of the Hexi Corridor in the spring of 2014 (from March to May) were studied, and the relationship between solar total radiation and net radiation in different pollution situations was analyzed. Moreover, the changes of solar radiation and PM 10 mass concentration in a typical dust process in April 2014, as well as the responses of ground meteorological elements were also analyzed. The results showed that in the west of the Hexi Corridor, solar total radiation and PM 10 mass concentration showed an increasing trend with fluctuation, and there was inverse correlation between them. The correlation was particularly obvious in dust days. The dust weather led to the increase of PM 10 mass concentration, so that the total radiation decreased. The net radiation declined in the daytime and rose at night. Dust weather is a major factor affecting air quality and total radiation.

New Characteristics of the Dust Weather in Northern Shaanxi in Recent 10 Years

[Objective] The research aimed to study new characteristics of the dust weather in northern Shaanxi in recent 10 years and correlation between dust weather and meteorological factor. [ Method] Based on observation data of 3 national basic meteorological stations （Yuyang District, Dingbian and Yan＇an） during 2001 -2010, the newest fact characteristics of temporal-spatial evolution for sand storm, sand blowing and floating dust in northern Shaanxi during 2001 -2010 were illustrated. Correlation between dust weather and meteorological factor （gale, precipitation and temperature） was analyzed. [Result] Compared with the 1990s, dust days in northern Shaanxi during 2001 -2010 still continued to decrease. There was no sand storm in Yan＇an. Sand storm days in northem region of north Shaanxi in most years was 1.0 -2.0 d. Sand blowing was main characteristics of the dust weather in northern Shaanxi, and proportion of the sand blowing days to dust days was 80% -90%. Dust days in Dingbi- an had good correlation with gale days, but gale days was smaller than dust days. That is to say, smaller wind force could induce dust weather. Decrease of the dust days presented inverse correlations with precipitaion and temperature. Precipitation increase and temperature rise could inhibit occurrence of the dust weather. Although total dust days decreased, sand storm in Yuyang District had increase tendency. [ Conclusion] The research had scientific, objective and practical significance for prediction of the climate change tendency in northern Shaanxi.

Experimental research on the mixed sand ratio and initial dry density of weathered sand improved expansive soil free load swelling rate

In this paper, through the indoor free load swelling rate test, expansive soil in a section of a first- class highway reconstruction project in Yichang City was studied. It emphatically analyzed the interrelations among free load swelling rate, non-load time, the proportion of mixed sand and initial dry density. Experimen- tal studies have shown that： Free load swelling deformation is mainly divided into three stages of rapid expan- sion, slow expansion and final stability; when the initial dry density is constant, free load swelling rate of the weathered sand modified soil will reduce rapidly before they slow down with the increase of sand proportion, and weathered sand modified soil free load swelling rate is not sensitive to the large amount of sand mixed; in the same mixed sand ratio, weathered sand modified soil free load swelling rate increases rapidly with the in- crease of initial dry density, there is a good linear correlation between them. To take appropriate control of the initial dry density during the expansive soil subgrade construction helps to reduce its swelling deformation and ensures the stability of the embankment.

On single particle breakage behavior of crushable weathered sands

This paper presents an experimental study on single particle breakage behavior of crushable weathered sands by a number of single particle uniaxial compression tests to comprehensively investigate the characteristics of single particle breakage,the probability of survival of single particle,and the effects of particle size and weathering on single particle strengths.The behavior of single particle under uniaxial compression falls into the mixed five phases:damage by chipping,elastic deformation,fragmentation by partial fracture,breakage by splitting,and the residuals,demonstrating the complexity and variability of the tensile strengths of single particles.The behavior of single particle breakage was quantified herein by the initial fracture and failure strengths of single particle.The probability of survival decreased as the characteristic stresses increased.An increase in the particle size or weathering number of single particle resulted in a reduction in the probability of survival of single particle.For a given probability of survival,the difference in the initial fracture characteristic stress and failure characteristic stress decreased with increasing particle size but showed a complex change with increasing weathering number.The probability of survival showed greater variability for the normalized initial fracture characteristic stress than for the normalized failure characteristic stress,implying that the initial fracture stresses of single particles diverged more than the failure stresses of the particles.The average initial fracture and failure characteristic stresses,and the initial fracture and failure characteristic stresses corresponding to 1/e(37%)survival of single particles decreased while increasing particle size or weathering number,but the decrease showed a sharper rate for smaller single particles with a lower weathering number.The ln-ln coordinates showed a linear representation of the failure characteristic stress and particle size,verifying the applicability of Weibull theory to single particle breakage.However,weathering resulted in downward translation and slight rotation of the linear relation of the failure characteristic stress and particle size in the ln-ln coordinates.