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.

Features of Sand-dust Deposits in Harbin City,China

From the sedimentologic view, this paper analyses the grain-size distribution and the chemical composition of the deposits from sand-dust storm, occurring in Harbin on March 20, 2002. The result indicates that there exist plentiful coarse matters in the sand-dust deposits in Harbin, and the sand-dust composition presents obvious three peak distribution characteristics, indicating that the sand-dust in Harbin is composed of multi-origin components. The grain-size composition consists of silt （4-8Φ）, accounting for 71.18% of the total, sand （〉4Φ）, 21.70%, and clay （〈8Φ）, only 7.13%. The average grain size （Mz） is 5.14Φ. The chemical elements of the deposits are mainly SiO2 and A1203 and Fe203, totally occupying 77.8%. The enrichment factors （EF） of Mg, K, Si, Fe, Mn, P, Ti, Co, Ni and V elements are all about 1, which mainly come fi＇om lithosphere source, while parts of Cu, Pb, Zn, Cr and Se elements are from pollution sources out of lithosphere source, and As, Cd and Sb elements are mainly from pollution sources. Based on the comprehensive analysis of grain-size, chemical composition, enrichment factor （EF）, discriminant function （DF） and matter source index （PI）, this paper points out that the grain-size distribution and element composition of the sand-dust deposits in Harbin are evidently different from the loess and sand-dust in Lanzhou, and that matter source of the sand-dust in Harbin is different from the loess in Northwest China and the sand-dust in Lanzhon. The sand-dust deposits in Harbin are an admixture of coarse grains transmitted in short distance and fine grains transported in long distance. The plentiful coarse grains of the sand-dust deposits in Harbin origin from sand of local spot, and are the near-souroe deposits transported by low altitude airflow.

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.

Particulate matter trends and quantification of the spring sand-dust contribution in Hohhot,Inner Mongolia,from 2013 to 2017

On 10 September 2013,the State Council promulgated the Action Plan for the Prevention and Control of Air Pollution(hereinafter referred to as the Action Plan).To study the variations in the air pollutant concentrations in Hohhot during the implementation of the Action Plan and the effects of various measures,the daily concentrations of air pollutants(fine particulate matter(PM_(2.5)),inhalable PM(PM 10),SO_(2),and NO_(2))in Hohhot published by the China Environmental Monitoring Station were obtained to analyze the general meteorological conditions in Inner Mongolia from 2013 to 2017.The variations and causes of the ambient PM concentration in Hohhot were examined,and the quantitative influence of sandstorms on the ambient PM concentration in Hohhot was analyzed by selecting the spring season with frequent sandstorms as an example.The results showed the following.(1)The air quality in Hohhot continuously improved,and compared with those in 2013,the PM_(2.5)and PM 10 concentrations decreased by 24.6%and 48.2%,respectively,in 2017.However,the air pollutant concentrations remained high,with the average PM_(2.5)and PM 10 concentrations exceeding the national secondary standards by 22.9%and 35.7%,respectively.(2)The reductions in the spring PM_(2.5)and PM 10 concentrations were 5.6%and 8.9%,respectively,and the annual decreases in the PM_(2.5)and PM 10 concentrations were 3.6 and 15.1μg m^(−3)yr−1,respectively,from 2013 to 2017.(3)The absolute contribution ranges of dust weather to the concentrations of PM_(2.5),PM 10,and TSP during 2013–17 were 0.6–5.2μg m^(−3),9.0–16.9μg m^(−3),and 14.7–30.0μg m^(−3),respectively,in Hohhot during the spring.

Detecting sand-dust storms using a wind-profiling radar

Sand-dust storm is a type of disastrous weather, typically occurring in arid and semi-arid climates. This study selected a region in the hinterlands of the Taklimakan Desert, called the Tazhong region, as the experimental area to quantitatively estimate the particle concentrations of sand-dust storms using the boundary layer wind-profiling radar. We thoroughly studied the radar echo signals and reflectivity factor features during the sand-dust storms. The results indicate that（1） under sand-dust storm conditions, boundary layer wind-profiling radar cannot capture the complete information regarding horizontal wind velocity and direction, but it can obtain the backscattering intensity of sand-dust storms; and（2） during sand-dust storms particle size distributions in the surface layer closely resemble log-normal distributions, with sand-dust particles sizes of 90–100 μm accounting for the maximum particle probability. Retrieved particle size distributions at heights of 600, 800, and 1000 m follow log-normal distributions, and the expected value of particle diameter decreases gradually with increasing height. From the perspective of orders of magnitude, the retrieved results for particle number concentrations and mass concentrations are consistent with previous aircraft-detected results, indicating that it is basically feasible to use boundary layer wind-profiling radar to quantitatively detect the particle concentrations of dust storms.

Sand-dust Storm, Population and Environment in Northwest China

Sand-dust storms are the result of the integrated influences of climate, geography, society and human factors. A theoretical framework is built to explain the coherence of population growth, agriculture change and environmental degradation. On the basis of the analysis of the causes of the sand-dust storm in terms of human factors, a discussion will be given to show that these factors are internally consistent with the theoretical framework. After that, it will look at China's Agenda 21 and try to find relevant measures to reduce such large sand-dust storms happening in Northwest China and eventually make this area develop sustainably.

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.

A Simulation Study on Channel Estimation for Cooperative Communication System in Sand-dust Storm Environment

There are many factors that influence the propagation of electromagnetic wave in the sand-dust storm environment, the scattering effect of dust particle is one of the major factors, so this paper focuses on the dust particles scattering function. The scattering of dust particles inevitably brings the multipath transmission of the signal, multipath propagation will bring the multipath fading of the signal. In this paper, we first investigate the use of AF and DF modes in a sand-dust storm environment. Secondly, we present a low-order modulation method should be used in cooperative communication system. Lastly, we evaluate the system performance for both of the moving nodes and power allocation. Experimental results validate the conclusion of theoretical derivation: the multipath fading is one of the main factors that affect the quality of signal transmission. Cooperative communication technology has good anti-fading ability, which can guarantee the signal transmission timely and correctly.

PROBLEMS CONCERNING SAND-DUST STORMS IN NORTHWEST CHINA

This paper describes an exceptionally severe sand-dust storm that occurred in Northwest China in 1993, and outlines the damage, characteristics and formative factors of the sand-dust storm and the demarcation of its prone zones, laying emphasis on the countermeasures to prevent and reduce such disasters. Finally the authors suggest setting up protective systems for oases and taking action to rehabilitate the blown sand-land on the northern side of the Great Wall on the Loess Plateau.

带电沙尘大气对微波量子照明雷达性能的影响

本文旨在研究带电沙尘大气对微波量子照明雷达性能的影响.基于Mie粒子散射理论,运用模拟离散随机分布粒子对光子多重散射的蒙特卡罗方法,对不同能见度及不同粒子带电量的沙尘大气的微波衰减进行分析.根据量子照明雷达理论,采用基于分束器理论的分光链路模型模拟沙尘大气信道,并根据量子雷达方程及量子检测错误概率理论,开展不同能见度带电沙尘大气对微波量子照明雷达的检测错误概率、信噪比和最大探测范围等影响研究,并与经典TMN雷达性能进行对比分析.结果表明,在沙尘大气中,量子照明雷达的性能随着能见度的增大而提高,粒子带电会引起信号衰减增大及系统性能下降,带电量的变化引起性能的改变是非线性的.当能见度较高时适当提高信号频率可提高量子照明雷达的性能,当能见度较低时频率提高带来的增益会小于衰减增大带来的性能下降,这种情况不宜增大频率.在与经典雷达的比较发现,在较低能见度及较低发射平均光子数时量子雷达性能较优,但随着光子数增加,优势逐渐降低.

PARAMETERIZATION OF MOBILIZATION AND TRANSPORT OF SAND-DUST DURING BLACK STORM AND MESOSCALE NUMERICAL EXPERIMENTS

The typical black storms or sand-dust storms in the northwestern China are generated and developed through an interaction between the specific large scale circulation pattern and mesoseale systems.The passing by/over a huge sand-abundant desert of a strong cold front with intensive frontal zone at mid and lower levels is a necessary condition for the formation and development of a black storm or a severe sand-dust storm.In order to investigate the mechanism of the sand-dust mobilization,transport and sedimentation during the black or sand-dust storms,a parameterization scheme of sand-dust source-sink terms and an equation of transport for the sand-dust were proposed and incorporated into the MM4 mesoscale model.The modified MM4 model was applied to the“May 1993”black storm case and succeeded in reproducing the evolution of the weather systems associated with the black-storm,the sand-dust concentration at surface layer and its vertical distribution,and the sand-dust sedimentation and transport.Our results show that the numerical simulating method by using a mesoscale model,with inclusion of an equation of the sand-dust transport and a parameterization scheme of the sand-dust source-sink terms,is a promising approach to study the mechanism for sand-dust mobilization,transport and sedimentation during a sand-dust storm event.

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。

基于Lab色彩空间的沙尘降质图像增强方法

针对沙尘天气导致的数字图像质量大幅下降问题,提出一种基于Lab色彩空间的沙尘降质图像增强方法。将沙尘图像增强分解为偏色校正与细节增强两个步骤处理。偏色校正部分包括去除色偏与亮度拉伸。首先对Lab与YUV色彩空间中的沙尘图像直方图偏移特点进行了分析,然后提出一种Lab空间偏色校正算法修正直方图偏移,并对初步去除偏色的图像进行亮度拉伸,提升图像对比度。在细节增强部分,引入一种基于饱和度估计透射率的去雾方法进一步增强图像细节信息。实验结果表明,相较于各对比算法,所提算法可以去除不同程度沙尘带来的色偏,且在面对中小型图像时具有最佳的时间性能表现。在量化指标方面,基于无参考感知的图像质量评估标准和基于熵的无参考图像质量评价标准分别提升了3.2%和10.7%。本文方法可以有效去除色偏,还原清晰图像。

The Variability of Spring Sand-Dust Storm Frequency in Northeast Asia from 1980 to 2011

The characteristic distributions of regional sand-dust storm （SDS） weather processes over Northeast Asia from 1980 to 2011 were investigated using the shared WMO surface station meteorological data, atmospheric sounding data, China high density weather data, NCEP/NCAR reanalysis data, as well as the archived original weather maps of China. The concentration-weighted trajectory （CWT） method was used to calculate the SDS frequency from the discrete station data and to track the large-scale regional SDS weather processes in Northeast Asia. A spline trend analysis method was employed to investigate the variability of the SDS weather systems. The results show that during 1980-2011, the SDS weather processes exhibit both a historical persistence and abrupt transitions with an approximate 10-yr high-low occurrence oscillation. Through composite analysis of atmospheric circulation during high and low SDS years, it is found that the SDS occurrences are closely related to the anomalies of arctic vortex and midlatitude westerly, and the circulation patterns around the Lake Baikal. During the high frequency years, the meridianal flows in the upper and mid troposphere above the high SDS corridor in East Asia （from the Lake Balkhash along Northwest and North China, Korean Peninsula, meridianal flows during the low SDS frequency years, the midlatitude regions. and Japan Islands） are apparently stronger than the favoring the development and transport of SDSs in the midlatitude regions.

The influence of the sand-dust environment on air-gap breakdown discharge characteristics of the plate-to-plate electrode

The experiments of plane-plane gap discharge was carried out in an environment of artificial sandstorm. By comparing and analyzing the differences in gap breakdown voltage between the sand & dust environment and clean air, some problems were investigated, such as effects of wind speed and particle concentration on the breakdown voltage, differences of gap discharge characteristics between the dust & sand medium and the clean air medium. The results showed that compared with the clean air environment, the dust & sand environment had a decreased gap breakdown voltage. The longer the gap distance, the greater the voltage drop; the breakdown voltage decreased with the increase of particle concentration in flow. With the increase of wind speed, the breakdown voltage decreased at the beginning and rose afterwards. The results of the paper may helpful for further research regarding the unidentified flashover and external insulation characteristics of the HV power grid in the dust & sand environment.

2021年宁夏两次持续沙尘重污染天气对比分析

为探究气象条件变化对宁夏沙尘重污染天气过程的影响特征,利用常规气象观测数据、NCEP再分析资料及环境空气质量数据,选取2021年1月11-14日和2021年3月14-19日两次沙尘重污染天气(分别简称“0113”过程和“0315”过程)为研究对象,基于天气形势、后向轨迹模拟及物理量场诊断等方法,对比两次过程影响系统及传输轨迹,探讨形成和维持机制.结果表明:①“0113”过程主要影响宁夏北部四市,“0315”过程影响整个宁夏,两次沙尘过程中重度及以上污染平均持续时间分别为35.0和105.2h,沙尘污染暴发阶段PM_(10)浓度平均值分别为1735和5265μg/m3.②“0113”过程为一次强度一般的锋面过境引起的沙尘重污染天气,稳定少动的青藏高压与其北侧蒙古热低压之间形成显著的气压梯度带,高空脊前多股强西北气流引起动量下传,使宁夏及上游地区大风将沙尘输送至宁夏造成重污染;“0315”过程为一次较强的典型锋面过境及蒙古气旋造成的持续沙尘重污染天气,蒙古冷高压受强盛蒙古气旋和青藏高原热低压夹击稳定少动,其西南、东南及东部与两个热低压形成气压梯度带,加之受地面冷锋过境影响,宁夏及周边地区多方向大风将沙尘向宁夏上空输送造成“0315”过程较“0113”过程污染更严重.③两次过程中沙尘均为境外和境内同时输送,“0113”过程为西北和偏西路径,传输距离长且高度较低;“0315”过程为西北、偏北和偏东路径,传输距离短且高度较高.④“0315”过程中蒙古国及我国新疆-甘肃一带负水平螺旋度中心值为“0113”过程的1.75倍,较强的辐合上升运动和西风气流将沙尘持续向宁夏上空输送并与本地沙尘叠加,上升和下沉运动交替使沙尘长时间悬浮于空中,而“0113”过程受多股强下沉气流造成沙尘迅速沉降至地面,污染快速减弱.研究显示:冷锋和蒙古气旋是宁夏沙尘重污染天气的主要影响系统,当有只冷锋过境时,上游沙尘传输高度低,到达宁夏上空沙尘粒子相对少,使宁夏沙尘重污染天气持续时间短且强度相对较弱;当伴有蒙古气旋活动时,沙尘传输高度高,到达宁夏上空沙尘粒子多,使宁夏沙尘重污染天气持续时间长、影响范围广且强度较强.

OBSERVATIONAL STUDIES ON SAND-DUST STORM IN HELAN MOUNTAINOUS AREA

According to the observation of the number and mass concentration spectra of atmospheric aerosols,the total suspended particulates (TSP) and their size distribution,micrometeorology, and the solar spectroscopic radiation,even neutron activation treatment of sand dust samples in Helan Mountainous area.the formation law of floating dust,blowing sand and sandstorm weather and the characteristics of climatic variation in this area and the influence of the Helan Mountain are counted and analyzed.In addition,the spectrum characteristics,optical depth and chemical composition of sand aerosol particles are also analyzed and discussed.

中国西北城市沙尘天气变化特征——以兰州为例

近年来,众多学者对我国西北地区沙尘暴的研究主要集中于大尺度、区域性,对城市沙尘暴研究较少。为了解城市沙尘暴的变化特征,本文以兰州为例,分析城市沙尘天气变化特征。结果表明:(1)兰州2009—2023年浮尘、扬沙、沙尘暴日数在时间序列水平上呈多段波动变化趋势,沙尘天气总日数在时间序列水平上整体呈0.66 d·a^(-1)微弱递减趋势。(2)兰州沙尘天气集中发生在春季,在3月断崖式上升后逐月递减,主要以浮尘为主,其次为扬沙、沙尘暴。(3) 2009—2023年兰州年均沙尘天气发生频次与风速呈正相关,是影响沙尘天气的主要气象因子,与相对湿度呈微弱负相关,与其余气象因素无明显相关关系。(4)浮尘日数存在2~3 a、4~7 a、8~23 a 3种时间周期尺度,呈多段不显著波动趋势,其中,8~23 a对应两个峰值,振幅最强,是浮尘波动的主周期。

干旱大陆性气候区城市大气颗粒物特征及来源分析——以吐鲁番市为例

本文以新疆典型干旱大陆性气候区城市吐鲁番市为例,依据2015—2017年3年以来的二氧化硫(SO_(2))、二氧化氮(NO_(2))、可吸入颗粒物(PM_(10))、一氧化碳(CO)、臭氧(O_(3))和细颗粒物(PM_(2.5))监测数据,分析了该市大气环境质量变化特征。结果表明,颗粒物是吐鲁番市乃至新疆的首要污染物,采暖季以PM_(2.5)为首要污染物,沙尘季以PM_(10)为首要污染物,夏季以O_(3)为首要污染物。吐鲁番市沙尘天气过程影响扣除后,PM_(2.5)/PM_(10)仍持续处于较高浓度范围,即不能完全消除沙尘天气对PM_(2.5)年均浓度的影响。综上所述,改善吐鲁番市大气环境质量需要从解决燃煤散烧、工业污染和交通污染三大问题上共同发力。