SEDIMENTARY CHARACTERISTICS AND CLIMATIC ANALYSIS OF EASTERLY DUST STORMS IN THE NEGEV (ISRAEL)

Sedimentary and meteorological characteristics of easterly dust storms causing severe damage in the Negev in November 1958 are analysed. Though the heavy storm originated in weather conditions outside of the affected area, the intense dustiness was of a more local nature. The sedimentological character of the dust indicates that the largest portion was of local origin, picked up by the turbulent current in the loess area of the northern Negev on its passage westward. Total quantity of sediment transported in the Beersheba Basin is estimated to be 10–20 million tons. The analysis of climatic data and of sedimentary characteristics of several other dust samples indicates that though severe dust storms can produce dramatic effects in transporting and deposition of aeolian dust, the rare occurrence of easterly dust storms does not make it likely that they were responsible for the import of aeolian sediments found in the northern Negev.     

亚洲粉尘的源区分布、释放、输送、沉降与黄土堆积

根据亚洲粉尘关键区域(中国沙漠、黄土高原、青藏高原和中国历史降尘区)大气气溶胶中15～28种元素的浓度-粒度分布、沉降速率和通量分析,以及元素示踪系统的进一步解析,发现中国北方沙漠存在两个粉尘地-气交换较活跃区域,即中国西部沙漠和北部沙漠高粉尘区,且证明这两个区域及其邻区是亚洲粉尘和黄土高原黄土主要源区的中心区域;通过对5个亚太区域粉尘沉降量的模式估算,得出亚洲粉尘释放总量每年约为800Tg,约相当于全球沙漠排放总量的一半;粉尘与黄土的对比表明,亚洲粉尘区域尺度输送受季风环流控制,但间冰期时并不取决于尘暴过程,而全球尺度输送主要由高空西风完成,无论冰期、间冰期均受尘暴过程控制;粉尘通量的结果表明干沉降是粉尘在黄土区沉降的主要过程,且晚第四纪粉尘沉积的再改造份额不超过其沉积总量的10%;元素示踪系统应用于风成黄土,发现在间冰期北部沙漠源区输出的粉尘量增加,而在冰期西部源区输出的粉尘量增加.这种晚第四纪亚洲粉尘“源区摆动”的快速变化其实是全球千年尺度气候变化的一环,并可视为过去北半球大气环流长期变化的代用序列.     

内蒙古中西部地区土壤水分对沙尘暴的贡献

以2001年4月至2002年 6月内蒙中部地区逐时观测的土壤水分资料为基础，论证了该区日土壤水分和日平均风速的变化规律，统计分析了日平均风速与土壤水分对沙尘暴的成生综合贡献。得出的主要结论是：①该地区沙尘暴发生时日平均风速的最小值是 3．5 m／s。如果日平均风速大于 8．0 m／s，预示着有沙尘暴的发生。②在平均风速大于 3．5 m／s的条件下，观测样本中 18．4％日数发生沙尘暴，而81．6％日数没有发生。说明大风的天气条件不应当被视其为沙尘暴的唯一重要的因子。③在同一地点、同样的风力条件下，在沙尘暴发生时，日平均风速与日平均土壤水分呈明显的反相关变化；而它们的反相关关系不明显时，沙尘暴就很少发生。     

内蒙古中西部地区土壤水分对沙尘暴的贡献

以2001年4月至2002年6月内蒙中部地区逐时观测的土壤水分资料为基础，论证了该区日土壤水分和日平均风速的变化规律，统计分析了日平均风速与土壤水分对沙尘暴的成生综合贡献。得出的主要结论是：①该地区沙尘暴发生时日平均风速的最小值是3．5m／s。如果日平均风速大于8．0m／s，预示着有沙尘暴的发生。②在平均风速大于3.5m／s的条件下，观测样本中18．4％日数发生沙尘暴，而81．6％日数没有发生。说明大风的天气条件不应当被视其为沙尘暴的唯一重要的因子。③在同一地点、同样的风力条件下，在沙尘暴发生时，日平均风速与日平均土壤水分呈明显的反相关变化；而它们的反相关关系不明显时，沙尘暴就很少发生。     

Characteristics of aerosol dust in fresh snow in the Asian dust and non-dust periods at Urumqi glacier no. 1 of eastern Tian Shan,China

Windblown mineral aerosol dust derived from the crustal surface is an important atmospheric component affecting the earth’s radiation budget. Deposition of atmospheric dust was measured in the fresh snow on glacier no. 1 at the headwater of the Urumqi River in eastern Tian Shan, central Asia. An analysis of seasonal variation of concentrations of dust particles in the snow suggests that the number concentration of dust particle is significantly high from April to June, which may be caused by Asian dust storms in the spring. The comparison of mass-size distribution of dust particles from April to August shows an obvious seasonal change trend. The distribution of particles changes from single model (3–21 μm) in the non-dust period before dust events in April, to bi-model (3–21 and 20–80 μm) during the Asian dust period, and to single model (3–21 μm) after July in the non-dust period again. The Ca²⁺ concentration in the fresh snow is also very high from April to June, while NH₄ ⁺ and SO₄ ²⁻, as water-soluble constituents, have concentration changes that are different from each other. Backward trajectory was also employed to examine the transport process of air mass in this region.     

Geochemistry and mineralogical composition of the airborne particles of sand dunes and dust storms settled in Iraq and their environmental impacts

Five dust storms that occurred in 2008 (15 March, 11 April, 28 April, 25, May and 26 June) in addition to the many sand dunes disseminated in the Western Desert of Iraq are sampled. The worse dust storm that occurred in Iraq in 11 April, 2008 covered 75% of the Iraq area and deposited 6.9?million tons approximately as a total weight of fallout during just 8?h, declining temperature 6°C. During the episodes of dust storms, visibility decreased enormously, no more than 30?m. Many people were taken to hospitals after sustaining breathing problems. Some of them died. Clay fraction is the dominant part in the dust storms forming 70% besides a little silt (20.6%) and sand (9.4%), then classified as mature arkose of clay to sandy clay, whereas sand dunes are formed from 72.7% sand, 25.1% silt and 2.19% clay, then classified as mature arkose of silty sand. Sand dunes have much maturity. Mineralogical composition of dust storms and sand dunes are Quartz (49.2%, 67.1%), feldspar (4.9%, 20.9%), calcite (38%, 5%), gypsum (4.8%, 0.4%), dolomite (0.8%, 1%) and heavy minerals (3.2%, 6.6%), respectively. Heavy mineral suites in the dust storms are represented by zircon, pyroxene, hornblende, chlorite and magnetite; whereas the sand dunes are represented by zircon, tourmaline, garnet and pyroxene, concentrated within sand fraction. Heavy minerals according to satellite images revealed the dry land of Sahara Desert in North Africa and the Arabian Peninsula as well as Syria and Jordan were a major source of the dust storms that have occurred in Asia, including Iraq.     

Regional characteristics of dust storms observed in the Alxa Plateau of China from 1961 to 2005

The Alxa Plateau has one of the highest frequencies of dust events in China and one of the greatest contributions to East Asian dust. We compiled climate and dust storm data for the Alxa Plateau based on observational data from ten meteorological stations from 1960 to 2005. Our analysis showed that Guaizihu and Minqin dust centers had >26 days per year with dust storms versus 7–13 days for other desert and Gobi regions on the plateau. Variations in dust storm frequency during the study period showed that dust storms increased during the 1960s (until 1972), decreased until the late 1990s, and then increased slightly until 2002. About 75.6% of dust storms occurred in March, April, May, June, and July. Between 78.2 and 88.1% of the dust storms occurred during the daytime and 28.9% of the dust storms occurred between 13:00 and 16:00. The mean durations of dust storms in the Alxa Plateau ranged from 715 to 3,462 min. The annual number of minutes of dust storms averaged >1,800 min in the western Alxa Plateau. Dust storm frequency was inversely related to duration: the longer the average duration, the lower the frequency of such storms.     

1955-2011年兰州沙尘暴、浮尘天气事件发生概率的Markov模型研究

依据甘肃兰州市1955-2010年沙尘暴、 浮尘天气事件年变化资料, 划分年强度分级, 应用Markov模型对其不同强度发生概率进行分析, 在此基础上预测和检验了2011年兰州沙尘暴浮尘天气事件的发生概率.结果显示: 2011年沙尘暴发生的特强年、 强烈年、 强发生年、 一般发生年和少发年的概率为,而事实上2011年发生沙尘暴0次,属于少发年, 符合预测结果; 2011年浮尘天气发生的特强年、 强烈年、 强发生年、 一般发生年和少发年的概率为,而事实上2011年发生浮尘9次,介于平常年和少发年范围, 符合预测结果.随着时间序列的延长, Markov模型可成为短期沙尘暴浮尘天气变化预测的有效途径.     

基于GRAPES的西北地区沙尘暴数值预报模式及其应用研究

介绍了中国气象局兰州干旱气象研究所和中国气象科学研究院数值预报研究中心合作研制的耦合于GRAPES（Global/Regional Assimilation and Prediction Enhanced System）的沙尘暴数值模式GRAPES_SDM。该模式包括沙尘的起沙、传输、吸湿增长、并合、干沉降与云下清洗等详细的物理过程，可以对沙尘暴的起沙和空气中沙尘浓度进行模拟和预报。在此基础上形成了西北地区的沙尘暴数值预报模式系统，并于2005年4月开始在兰州中心气象台试运行，同时还将模式结果与卫星遥感资料反演的沙尘暴监测结果进行了对比验证。以2005年4月17~19日和5月28~29日发生在西北地区的2次强沙尘暴为例，利用GRAPES_SDM对这两次沙尘天气的起沙、传输、扩散直至消散进行了数值模拟。结果表明，模式输出的沙尘时空分布与实况观测和卫星云图监测的沙尘分布范围基本一致，说明该模式系统对西北地区沙尘暴天气的起沙、传输有较好的模拟和预报能力。     

Spatial distribution of dust deposition within a small drainage basin: Implications for loess deposits in the Negev Desert

Loessial colluvial sediments and aeolian aprons are common deposits in the Negev Desert Highlands. In an attempt to monitor the amounts and distributional pattern of loess, monthly dust measurements were carried out during 2004 to 2006 in 10 cm diameter traps located at 18 stations along four slopes, north‐facing, south‐facing, east‐facing and west‐facing in a second‐order drainage basin near Sede Boqer, Negev Desert Highlands, Israel. Annual total dust depositions ranged between 110 g and 178 g m^?2 with an average of 151·1 g m^?2. The average annual dust deposition in the catchment was 23·5% higher than the average amount recorded at the hilltops (122·4 g m^?2) and may be a consequence of sheltering opportunities in the hilly topography. When analysed according to season and aspect, significantly higher monthly amounts were received during the wet rainy season of December to March (17·0 g m^?2), in comparison with the rest of the year (8·1 g m^?2). As for the aspect, while no significant differences characterized north‐facing and south‐facing slopes, east‐facing slopes received significantly higher amounts (by 43·3%) than west‐facing slopes, pointing to preferential dust deposition at the leeward slope. Concurring with the classical model that anticipates higher dust deposition at the leeside slope, but in disagreement with some reports published in the literature, the findings of this study were also supported by a field survey that showed preferential loess accumulation at the eastern and north‐eastern aspects. These findings may shed light on distributional patterns of colluvial sediments and aeolian aprons in the Negev, on soil‐forming processes and on past cycles of dust deposition.     

有关中国黄土高原黄土物质的源区及其输送方式的再评述

仅通过对黄土的研究来认识黄土物质的源地和输送方式、沉降过程往往需要假设和推测一些问题,不够直接和全面,借助对沙漠和大气中沙尘粒子本身的研究则可以更清晰地认识它们.文章在以往对黄土物质源区、输送和沉积过程研究的基础上,对有关这些问题的研究进展,特别是2000～2006年以来的进展给出了进一步的评述.结果表明:蒙古源区、以塔克拉玛干沙漠为主体的中国西部沙漠源区和以巴丹吉林沙漠为中心的中国北部沙漠源区贡献了亚洲沙尘释放总量的约70%,它们可视为亚洲沙尘的3个贡献量最大的源区,也可视为是黄土高原黄土物质的主要源地;有关亚洲沙尘的输送,在接近其源区的区域其沙尘浓度峰值在1km及其以下,在中国内陆其峰值通常在1～3km高度,在日本等东亚区域在2～4km高度,在太平洋中部峰值位于4～5km高度,在美国西部在5～7km的位置.通常,亚洲沙尘的区域尺度输送主要受近地面层东亚冬季风的控制,沙尘穿越太平洋的跨洲输送模式与全球尺度的大气环流变化紧密相关,特别是受中纬度西风带的影响.关于黄土高原黄土物质的沉降和堆积,近地面层东亚冬季风起到的是控制性的作用,沙尘在黄土高原的沉降以干沉降为主.晚第四纪黄土-古土壤中的90%以上是亚洲沙尘粒子的沉积物,不到10%受到了再作用过程的影响.     

Synoptic analysis of dust storm over Arabian Peninsula: a case study on February 28, 2009

Sand and dust storms are causing hazards and problems in aviation as well as the dangers and distresses they cause on living things. The low meteorological visibility, the presence of strong winds with gust, and the transport of dust and sand particles by the wind are dangerous on landing and departure of aircrafts, and even on planes that are parked. The main aim of the study is to examine the meteorological conditions causing the dust storm that took place in the Arabian Peninsula on February 28, 2009, and to determine the source of dust caused dust storm, sand storm, blown sand, and blown dust at the airports. Within the scope of the study, aviation routine weather report (METAR) and aviation selected special weather report (SPECI) reports have been assessed at many airports over Arabian Peninsula (AP), the northern part of the AP and North Africa. As model outputs; NCEP–DOE Reanalysis 2 data, BSC–DREAM8B, and HYSPLIT model were used. In the satellite images; METEOSAT MSG dust RGB images, MODIS, and Kalpana-1 data were used. According to obtained results, dust storms were detected in Bahrain, Kuwait, Saudi Arabia, and United Arab Emirates (UAE). At Al-Ahsa Airport in Saudi Arabia, the lowest visibility measured on February 28, 2009, dropping to 200 m, which was dominated by blowing sand. The source region of the dust observed at Dubai Airport in UAE is the eastern regions of the Rub’al Khali Desert located between Saudi Arabia, Oman, and UAE.     

沙粒不能“远走高飞”———有关“尘暴”的一条根本原理

沙与尘虽然都是岩石物理风化的产物, 但在风力作用下, 习性截然不同。拜格诺用严格的物理实验证明, 尘粒能随风远走高飞, 而沙粒却只能在地面附近跳跃前进。从北方侵袭华北平原的所谓沙尘暴, 实质上都是尘暴。对历次重大天气事件沉积物的分析, 也完全证明了这一点。因此, 尘暴物质的源头不是来自有沙, 而是有尘的地方; 从而可以使人们采取正确的治理方法。      

中国北方过去2000年沙尘事件与气候变化*

文章依据冰芯、树木年轮等自然记录和历史文献记录,分析了中国北方不同地区近2000年的沙尘事件及其与气候变化的关系。结果表明,在干旱区西部,历史时期的沙尘变化主要受温度变化的制约,无论在10年尺度,还是百年尺度上,沙尘事件与温度变化均表现为显著的反相关,即气候寒冷期与沙尘频发事件相对应,气候温暖期与沙尘发生变弱期一致;在半干旱区,在10年尺度上温度和降水序列与沙尘发生频率均显著负相关,但在百年尺度上沙尘与降水变化的关系更为密切;在干旱区东部,沙尘与气候变化的关系具有明显的过渡性特征,气候变化对沙尘事件的作用主要在百年尺度上体现出来,沙尘与温度记录的负相关比降水更好,在10年尺度上气候与沙尘序列尽管也是负相关,但不显著。通过对现代气象记录的气温、降水变化和沙尘事件频数分析,其结果与历史时期情况基本一致。     

Mapping and monitoring of dust storms in Iran by fuzzy clustering and remote sensing techniques

In this research, the frequency of dust storms was prepared at 87 synoptic stations for the period of 1987–2013. These data were classified by means of Fuzzy c-means clustering algorithm. Satellite images of MODIS and brightness temperature index were also used for detection and tracking dust storm of 30 Jun 4 July 2008. The results indicated that Iran is classified in five clusters by the dust-storm-frequencies from which, cluster 5 is reclassified in three clusters because of its wide range. The maximum number of days with dust storms was observed in cluster 1 that includes only Zabol station with the frequency of 790 days with the duration 1987–2013. The minimum number of days with dust storms was observed in cluster 5-3 that includes the stations located in portions of North, Northwest, Northeast Iran and the higher elevations of the Zagros in western Iran. A case study about a severe dust storm in Iran using satellite images indicate that brightness temperature index (BTI) is a desired index for detection and monitoring of dust storms. The source of the investigated dust storms is Iraq and South of the Arabian Peninsula that had influenced the western half of Iran in several days. The frequency of dust storms increased markedly in the west, southwest of Iran and Persian Gulf around as main receptors from emerging dusty areas but it increased slightly in the eastern half of Iran.     

Dust emission from desertified lands in the Heihe River Basin,Northwest China

The annual and seasonal dust emissions were calculated for eight types of desertified lands at 120 sites in the Heihe River Basin of northwestern China. The results showed that dust emission rates increased from the middle to the lower reaches of the river by a factor of up to 10³. There two strongest areas of dust emission are the dried-up Gaxun Lake with a dust emission rate of 1.6 t ha⁻¹ year⁻¹, and the desertified grassland areas around the abandoned Heicheng City, with a dust emission rate of 0.6–0.7 t ha⁻¹ year⁻¹. The total annual dust emissions with their particle diameters less than 50, 30, and 10 μm were 1.71 × 10⁶, 1.11 × 10⁶, and 0.555 × 10⁶ t, respectively. Dust emission rates showed striking seasonal variations, with the maximum value (45%) occurring in spring and the minimum value (13.5%) in summer. The mineral aerosol-size distributions were also measured and the results showed that the size distributions for dust and non-dust events were both trimodal, in contrast with the widely accepted view that primary particles such as aeolian dust are coarse, whereas particles less than 1 μm in diameter are mainly secondary particulate substances such as ammonium nitrate, ammonium sulfate, and organic matter.     

苏干湖沉积物粒度组成记录尘暴事件的初步研究*

文章通过分析苏干湖表层沉积物、流域表层沉积物、大气降尘以及湖泊冰面囚固碎屑颗粒等的粒度组成,比较了流域地表沉积与湖泊沉积物粒度组成的差异和苏干湖表层沉积粒度组成的空间变化。初步认为苏干湖沉积物粗颗粒组分(>63μm)主要由风力搬运入湖,>63μm组分的含量可以用来指示研究区尘暴事件的演化。结合湖泊沉积岩芯纹层计数年龄,重建的1000年来尘暴演化历史显示,在1210A.D.之前尘暴事件较弱,且变化幅度较小;1210A.D.以来则表现出高频率或者高强度,其中13世纪上半叶以及17世纪的高值段与东部降尘变化历史一致。就气候变化的特征时段(中世纪暖期、小冰期等)而言,尘暴事件主要与气候变冷情况下较强的盛行风场有关;而极端干旱区有效湿度的增加可能有利于地表粉尘的释放,助长了尘暴事件的发生。     

Socioeconomic effect of dust storms in Kuwait

Kuwait is an arid country with an annual average rainfall of about 110 to 120 mm. Hence, dust storms have become a common environmental crisis. Although the dry summer months commonly have more dust storms, in recent years, dust storms occur more frequently in the spring season as well. Accumulated data of dust storms in Kuwait for the past 14 years (2001–2014) showed that the month of March had the highest number of dust storms (total 19), which is rather unusual, with an average of 8 dust storms per year (year 2008 had the highest dust storms of total 22). This study explored four socioeconomic effects of dust storms in Kuwait, specifically traffic accident rates, oil export loss due to close out of marine terminals, airline delays due to airport operation shutdown, and agriculture degradation. Statistical analysis using t test and Pearson correlation showed no apparent relationship between dust storms and traffic accident rates or agricultural production; however, loss of oil export and flight delay cost were affected by dust storms. There has been very few published research on the socioeconomic impact of dust storms; this is the first paper that explores the detailed socioeconomic effect of dust storms in Kuwait.     

京津地区“沙尘暴”的性质和治理——以北京2006年4月16日的尘暴为例

依据粒度分析、电镜扫描、能谱分析、常温水溶盐检测、宏观表象特征研究和实地调查，证实北京2006年4月16日的所谓“沙尘暴”是尘暴，干涸盐湖是京津尘暴的重要源区。因此，要治理京津地区的尘暴，就必须修复干涸盐湖区的生态环境，而不能像过去那样去治理沙漠。要修复干涸盐湖区的生态环境，一定要用现代生态环境地质学的理论和方法去研究干涸盐湖区在地质历史时期植被演化的趋势，筛选出最适合当地生态环境的土著先锋植物种群，并用土著先锋植物种群对尘源区进行“地毯式”的覆盖，而不能用种树去阻挡它，因为再高的树林也挡不了从2000-3000m以上高空飘来的浮尘。     

X-ray Diffraction of Dust Particles in Spring Beijing

X-ray diffractometry was utilized to study the mineralogical characteristics of the inhalable particles (PM10) sampled during two dust storms in Beijing city on March 18th and May 21st, 2008. We confirm, for the first time, that there stably exists ammonium chloride in the atmosphere when temperature is low. The total sulfates particles were affected by relative humidity. Both species and concentration of sulfates decreased first and then grew back by the end of each dust storm. Koninckite, a phosphate mineral never reported as particulate aerosol before, was identified. Meanwhile, our result shows that a chemical modification on dust minerals occurs during long range transportation. PM10 samples collected during the period of dust storms were dominated by crustal minerals such as quartz, illite/ smectite, illite, chlorite, feldspar and calcite, and were notably higher in concentration than that in normal periods of time. The amounts of total sulfates, calcite and feldspar altered in each dust storm. It is derived from 24-hour isentropic backward trajectories that two dust events in spring 2008 originated in different sources.