辽宁省沙尘天气分析

以1971-2005年辽宁60个站沙尘天气资料为基础,从年代际变化、季节变化、空间分布特点等方面对浮尘、扬沙、沙尘暴、沙尘天气综合影响程度进行了统计分析。结果表明:辽宁的沙尘天气年代际变化明显,且多发生在春季(4月最多),沙尘天气主要在3月下旬到4月下旬出现在沈阳西北部、阜新以及朝阳北部地区。结合辽宁的气候、空间特点,从沙源、大风、不稳定层结3方面分析了辽宁沙尘天气的形成以及时空分布不均的原因,简要介绍了辽宁防沙的措施、效果以及辽宁省气象台沙尘暴短期预报方法。     

内蒙古一次特强沙尘暴大风成因分析

2010年3月19日,内蒙古中西部地区发生了近几年最严重的沙尘暴天气。沙尘暴天气由蒙古国西部起沙,在内蒙古中西部地区加强,随着天气系统的演变,地面形成强沙尘暴或特强沙尘暴天气。利用常规观测资料及数值预报产品资料对3.19沙尘暴天气过程进行诊断分析,得到以下结论:3.19强沙尘暴、特强沙尘暴天气过程,是近地面前期强烈增温,导致地表热力不稳定,由蒙古气旋产生上升运动起沙。高空西北气流上,斜压扰动不稳定发展,高空冷平流激发了垂直于地面的锋面次级环流,地面气旋转为强冷锋过境,内蒙古中西部地区产生强沙尘暴天气。高空急流对沙尘暴天气的产生具有重要作用。高空急流出口区右侧,下沉气流落于地面冷锋后,引起大风,加强了沙尘暴天气。在冷锋移动过程中,冷高压强度少变,处于其前沿锋区内的山西、河北、河南、山东等地产生了扬沙或沙尘暴天气。     

内蒙古沙尘暴的成因、趋势及其预报

本文利用内蒙古1961～2001年的天气气候资料,对内蒙古中西部地区沙尘暴作了统计分析,阐述了沙尘暴的危害并给出了沙尘暴的基本定义。分析了引起沙尘暴的天气和气候因子的变化趋势,研究了他们对沙尘暴的影响,结果表明近40年内蒙古的沙尘暴总体呈减少趋势,但从1998年开始有所增加;沙尘暴的空间分布以阿拉善盟偏北地区为最高发区;降水、气温、大风、寒潮、北半球极涡、西太平洋副热带高压、亚洲西风环流、东亚大槽和南方涛动等天气和气候因素均对该地区沙尘暴的发生有不同程度的影响。     

中国北方沙尘暴研究的若干进展

为了回顾总结中国北方沙尘暴研究的现状,本文评述了近20多年来中国北方沙尘暴研究的三个主要阶段,从沙尘观测、气候学、预报、变化趋势以及防御对策等6方面简要评述了它的研究进展和问题。指出北方沙尘主要源于中国西北及蒙古地区;随沙尘天气强度逐渐加强,不同沙尘天气时地面沙尘浓度约按3倍的比率依次递增;揭示了我国北方的五大沙尘暴多发区;主要有纯冷锋型和冷锋加中系统混合型两类沙尘暴爆发环流型;近50年来的沙尘暴活动呈波动变化,这与生态环境恶化,特别是东亚大气环流的年代际变化有关;防御沙尘暴重点要抓五大多发区生态环境的治理及沙尘暴预警系统的建立。     

大陆沙尘事件对台湾地区影响之政策初探

1　前言沙尘暴对空气品质的影响,近年来受到各国政府与学界的重视与探讨。在台湾地区,沙尘事件源起於大陆内地的沙尘暴,在特殊天气条件下,经过长程输送而抵达。有鉴於此,环保署推动“大陆沙尘密集观察计书”结合国内相关学者与监测设备,对大陆沙尘事件之预报、监测、健康评估、     

对1958-2000年山西沙尘天气的分析

本文分析了山西省1958—2000年16个气象监测站记录的沙尘天气资料,分析表明:山西沙尘天气主要发生在西北地区,沙尘暴、扬沙和浮尘发生频率的最大值分别为:5.3天/年、27.6天/年和23.8天/年。近43年山西省沙尘天气呈减少趋势,1966年是山西沙尘天气最多的一年,16个站累计有94天沙尘暴天气、448天扬沙天气、626天浮尘天气。春季为沙尘天气的频发期,沙尘暴占到77.6%,扬沙占到61.5%,浮尘占到59.5%;4月是沙尘天气发生最多的月份,沙尘暴占到44%,扬沙占到26.6%,浮尘占到25.4%。对沙尘暴的分析还发现,在1958-2000只有五寨记录到4次特强沙尘暴,强沙尘暴也呈减少的趋势,1966年最多,1989-2000年没有强沙尘暴出现的记录。沙尘暴大多发生在13点至20点之间,占沙尘暴发生总次数的69.1%。     

阿拉善盟一次区域性大风沙尘暴天气过程成因分析

沙尘暴是发生在干旱、半干旱荒漠化地区的主要灾害性天气之一,对其形成过程及成因探讨能为沙尘暴监测和预警提供参考。以2019年5月11日阿拉善盟一次区域性大风沙尘暴天气为例,在气象实时监测数据基础上,从地面气象要素变化、环流特征、动力条件和热力条件等方面对此次沙尘暴天气过程成因进行了探讨和分析。结果表明:1)阿拉善盟大风沙尘暴最强时段为午后至傍晚,沙尘暴发生时,气压和极大风速急剧增加,气温和能见度明显下降。2)大风沙尘暴的发生与500 hPa冷平流触发作用、700 hPa大气斜压性作用、高空动量下传作用、变压梯度风、锋生作用以及必要的大气层结条件之间存在着密切联系,表明控制大风沙尘暴形成的因素复杂。3)不同地区以及不同时间内发生大风、沙尘暴天气所需的风速条件不一致,强冷空气的侵入是沙尘暴发生的前提条件。此外,混合层,即不稳定层结是产生大范围沙尘暴天气的必要条件,在大风条件具备,但无混合层出现时,沙尘暴天气较难形成。     

静止气象卫星监测沙尘暴天气的方法与应用研究

本文对静止气象卫星监测沙尘天气的方法进行了研究 ,对其监测结果与极轨气象卫星的监测结果和地面观测结果做了对比分析。应用该方法研究了影响内蒙古的 9次强沙尘暴天气的沙尘起源地和沙尘的扩散过程 ,并对近年来影响中国北方最强的一次沙尘暴天气的发生、发展过程进行了动态的监测和预警。     

1961-2017年南疆地区沙尘天气的时空变化特征及影响因素分析

利用南疆地区49个地面气象站1961-2017年沙尘资料,通过Mann-Kendall突变检验法、 IDW插值法、多元回归分析和相对贡献率等方法,对南疆地区沙尘天气的月、季和年及年代的时空变化特征及影响因素进行分析。结果表明:近57a南疆地区沙尘天气呈极显著波动下降趋势,减速为-1.06d/a,其中浮尘日数减速最大(-8.6d/10a);沙尘变化特征表现为单峰式的先增后减;沙尘暴、扬沙和浮尘日数突变年为1989、1995和1994年;沙尘天气具有季节性、区域性差异,春夏秋冬分别为31.4、20.9、11.4和6.8d,季节变化表现为春季(-4.1d/10a)最大,年内月份均表现显著减少趋势;浮尘、沙尘暴和扬沙均呈现南多北少的纬向特征,主要发生在和田和巴州地区的南部,且绝大部分站点沙尘天气呈现显著减少趋势;风速、气温日较差与沙尘天气日数呈显著正相关,对沙尘天气的相对贡献率为51.2%和13.1%,水汽压、气温、最低气温、降水量呈显著负相关,贡献率为20.4%、9.5%、0.5%和0.2%,影响排序为风速>水汽压>气温日较差>气温>最低气温>降水量,风速对沙尘天气发生的影响占主导地位。综上所述,风速、下垫面的干湿状况、气温和冷空气活动等因素是南疆沙尘天气发生的主要因素。研究成果可为南疆地区绿洲合理扩张和沙土资源利用提供科学依据。     

降尘空间分布与沙尘天气日数关系研究

降尘是沙尘暴、浮尘、扬沙等沙尘天气过程的反映,文中以甘肃省10个监测点15年(1986-2000年)降尘监测数据及沙尘天气日数数据,讨论降尘空间分布与沙尘天气日数之间的相关性,建立降尘与沙尘事件之间的回归方程。结果表明:在沙尘暴区和非沙尘暴区,降尘与沙尘天气的回归方程不同,前者沙尘暴系数(1.32)小于后者沙尘暴与扬沙和的系数(1.66),可以判断后者较之前者降尘量受沙尘暴和扬沙日数影响更大,可以突现出后者沙尘天气主要以浮尘为常态形式出现。前者浮尘系数远大于扬沙系数(3.72>0.21),表明前者降尘量受浮尘影响大于扬沙。前者常数项(291.6)明显大于后者(235.2),这代表两地区降尘量的背景值的不同。回归方程很好地解释了不同地区降尘与沙尘天气日数之间的关系。将降尘与沙尘天气日数的回归方程应用到研究区,求得研究区各气象站点降尘数据,结合GIS空间插值,绘制出该研究区降尘空间分布图。     

中国西北干旱半干旱区阿拉善沙漠和黄土高原的物源分析

中国北方沙漠、黄土高原和青藏高原是亚洲粉尘释放的关键区域,元素示踪研究表明中国西部沙漠和北部沙漠是亚洲粉尘和黄土高原黄土的主要源区.通过收集总结大量的大气观测、地球化学、地形数据,对比当前研究已得到粉尘的成果和释放模式,初步认为中国黄土物质来源于阿拉善高原的巴丹吉林沙漠与腾格里沙漠.这两个沙漠(包括阿拉善高原的戈壁)的...     

内蒙古阿拉善盟2000年土地沙漠化遥感监测

以阿拉善盟2000年TM卫星影像遥感信息为主要依据,根据中国北方土地沙漠化动态分类系统,在遥感影像上进行解译和面积量算,获得了阿拉善盟2000年土地沙漠化状况:沙漠化土地总面积3666232.9hm2,占土地总面积的15.48%。阿拉善盟主要的沙漠化类型为沙丘活化或流沙入侵(1846880hm2)、灌丛(草地)沙漠化(735369.5hm2)、砾质沙漠化(1064944hm2)和耕地沙漠化(19039hm2)。沙丘活化或流沙入侵主要分布在阿拉善左旗境内,巴丹吉林沙漠与腾格里沙漠和乌兰布和沙漠之间的一些低山丘陵和荒漠干草原上;灌丛(草地)沙漠化主要分布在阿拉善东部;砾质沙漠化主要分布在阿拉善盟的西部,尤其以额济纳旗最多;耕地沙漠化主要集中在额济纳绿洲。     

Wind regimes and associated sand dune types in the hinterland of the Badain Jaran Desert,China

Wind controls the formation and development of sand dunes. Therefore, understanding the wind regimes is necessary in sand dune research. In this study, we combined the wind data from 2017 to 2019 at four meteorological stations (Cherigele and Wuertabulage stations in the lake basins, and Yikeri and Sumujilin stations on the top of sand dunes) in the hinterland of the Badain Jaran Desert in China, with high resolution Google Earth images to analyze the correlation between the wind energy environments and dune morphology. The results of data analysis indicated that both the wind direction and sand drift intensity exhibited notable spatial and temporal variations. The highest level of wind activity was observed in spring. Northwesterly and northeasterly winds were the dominant in the Badain Jaran Desert. At the Cherigele, Wuertabulage, and Yikeri stations, the drift potential (DP) was below 200.00 vector units (VU). The wind energy environments in most areas could be classified as low-energy environments. The resultant drift direction differed at different stations and in different seasons, but the overall direction was mainly the southeast. The resultant drift potential (RDP)/DP ratio was greater than 0.30 in most parts of the study area, suggesting that the wind regimes mainly exhibited unimodal or bimodal characteristics. Differences between the thermodynamic properties and the unique landscape settings of lakes and sand dunes could alter the local circulation and intensify the complexity of the wind regimes. The wind regimes were weaker in the lake basins than on the top of sand dunes. Transverse dunes were the most dominant types of sand dunes in the study area, and the wind regimes at most stations were consistent with sand dune types. Wind was thus the main dynamic factor affecting the formation of sand dunes in the Badain Jaran Desert BJD. The results of this study are important for understanding the relationship between the wind regimes and aeolian landforms of the dune field in the deserts.     

巴丹吉林-腾格里沙漠间沙丘活化带发展过程及其驱动力分析

基于1989,1999年和2007年TM/ETM＋影像,从土地利用变化的视角分析巴丹吉林-腾格里沙漠间沙丘活化带的发展过程,并探讨沙丘活化带发展的驱动因素。分析表明：①1989-2007年,研究区沙地和耕地面积增加,草地、盐碱地和沼泽地面积减少,景观破碎化程度加剧,沙地斑块质心向西北偏移,即腾格里沙漠西北缘向巴丹吉林沙...     

Monitoring desertification processes in Mongolian Plateau using MODIS tasseled cap transformation and TGSI time series

Most remote sensing studies assess the desertification using vegetation monitoring method. But it has the insufficient precision of vegetation monitoring for the limited vegetation cover of the desertification region. Therefore, it offers an alternative approach for the desertification research to assess sand dune and sandy land change using remote sensing in the desertification region. In this study, the indices derived from the well-known tasseled cap transformation(TCT), tasseled cap angle(TCA),disturbance index(DI), process indicator(PI), and topsoil grain size index(TGSI) were integrated to monitor and assess the desertification at the thirteen study sites including sand dunes and sandy lands distributed in the Mongolian Plateau(MP) from 2000 to 2015. A decision tree was used to classify the desertification on a regional scale. The average overall accuracy of 2000, 2005, 2010 and 2015 desertification classification was higher than 90%. Results from this study indicated that integration of the advantages of TCA, DI and TGSI could better assess the desertification. During the last 16 years, Badain Jaran Desert, Tengger Desert, and Ulan Buh Desert showed a relative stabilization. Otindag Sandy Land and the deserts of Khar Nuur, Ereen Nuur, Tsagan Nuur, Khongoryn Els, Hobq, and Mu Us showed a slow increasing of desertification, whereas Bayan Gobi, Horqin and Hulun Buir sandy lands showed a slow decreasing of desertification. Compared with the other 11 sites, the fine sand dunes occupied the majority of the Tengger Desert, and the coarse sandy land occupied the majority of the Horqin Sandy Land. Our findings on a three or four years' periodical fluctuated changes in the desertification may possibly reflect changing precipitation and soil moisture in the MP. Further work to link the TCA, DI,TGSI, and PI values with the desertification characteristics is recommended to set the thresholds and improve the assessment accuracy with field investigation.     

Wind tunnel experiments on dust emissions from different landform types

The measurement and assessment of dust emissions from different landforms are important to understand the atmospheric loading of PM10(particulate matter ≤10 μm aerodynamic diameter) and to assess natural sources of dust; however, the methodology and technique for determining the dust still present significant research challenges. In the past, specialized field observation and field wind tunnel studies have been used to understand the dust emission. A series of wind tunnel tests were carried out to identify natural sources of dust and measure the magnitudes of dust emissions from different landforms. The method used in this study allowed the measurement of the PM10 emission rate using a laboratory based environmental boundary layer wind tunnel. Results indicated that PM10 emissions demonstrated strong temporal variation and were primarily driven by aerodynamic entrainment. Sand dunes, playa, and alluvial fans had the largest dust emission rates(0.8–5.4 mg/(m~2·s)) while sandy gravel, Gobi desert and abandoned lands had the lowest emission rates(0.003–0.126 mg/(m~2·s)). Dust emissions were heavily dependent on the surface conditions, especially the availability of loose surface dust. High dust emissions were a result of the availability of dustparticle materials for entrainment while low dust emissions were a result of surface crusts and gravel cover. Soil surface property(surface crusts and gravel cover) plays an important role in controlling the availability of dust-sized particles for entrainment. The dust emission rate depended not only on the surface conditions but also on the friction velocity. The emission rate of PM10 varies as a power function of the friction velocity. Although dynamic abrasion processes have a strong influence on the amount of dust entrainment, aerodynamic entrainment may provide an important mechanism for dust emissions. Large volumes of dust entrained by aerodynamic entrainment cannot only occur at low shear velocity without saltation, but may dominate the entrainment process in many arid and semi-arid environments. So it may also be responsible for large magnitude dust storms. Playa and alluvial fan landforms, prior to developing a surface crust, may be the main sources of dust storms in Qinghai Province.     

Predicting of dust storm source by combining remote sensing,statistic-based predictive models and game theory in the Sistan watershed,southwestern Asia

Dust storms in arid and desert areas affect radiation budget, air quality, visibility, enzymatic activities, agricultural products and human health. Due to increased drought and land use changes in recent years, the frequency of dust storms occurrence in Iran has been increased. This study aims to identify dust source areas in the Sistan watershed (Iran-Afghanistan borders)-an important regional source for dust storms in southwestern Asia, using remote sensing (RS) and bivariate statistical models. Furthermore, this study determines the relative importance of factors controlling dust emissions using frequency ratio (FR) and weights of evidence (WOE) models and interpretability of predictive models using game theory. For this purpose, we identified 211 dust sources in the study area and generated a dust source distribution map-inventory map-by dust source potential index based on RS data. In addition, spatial maps of topographic factors affecting dust source areas including soil, lithology, slope, Normalized difference vegetation index (NDVI), geomorphology and land use were prepared. The performance of two models (WOE and FR) was evaluated using the area under curve (AUC) of the receiver operating characteristic curve. The results showed that soil, geomorphology and slope exhibited the greatest influence in the dust source areas. The 55.3% (according to FR) and 62.6% (according to WOE) of the total area were classified as high and very high potential dust sources, while both models displayed acceptable accuracy with subsurface levels of 0.704 for FR and 0.751 for WOE, although they predict different fractions of dust potential classes. Based on Shapley additive explanations (SHAP), three factors, i.e., soil, slope and NDVI have the highest impact on the model's output. Overall, combination of statistic-based predictive models (or data mining models), RS and game theory techniques can provide accurate maps of dust source areas in arid and semi-arid regions, which can be helpful for mitigation of negative effects of dust storms.     

策勒绿洲-荒漠过渡带风沙前沿近地表沙尘水平通量观测

沙漠地区近地表水平输送的沙尘物质通量及其随高度的变化是沙尘输送过程的重要表现特征。在塔克拉玛干沙漠南缘策勒绿洲-荒漠过渡带风沙前沿平坦沙地的风沙观测场,利用BSNE集沙仪对近地表（2 m）不同高度沙尘物质的水平输送进行了观测,对其随高度变化特征进行了分析,并对近地表水平运动的沙尘通量进行了计算。结果表明：观测点沙尘物质的水平通量随高度的增加而减小,与高度的关系可用幂函数和指数函数表示;55%～58%的沙尘量在地表0.5 m高度以内传输;73%～75%在地表1 m高度以内传输;87%～89%在地表1.5 m高度以内传输;2010年5月25日至2011年5月24日,通过0～2 m高度的单宽总输沙量为1 846.7 kg•m^-1;其中PM80、PM50的输送量分别为1 192.0 kg•m^-1、387.9 kg•m^-1。     

New evidence for the links between the local water cycle and the underground wet sand layer of a mega-dune in the Badain Jaran Desert,China

Scientists and the local government have great concerns about the climate change and water resources in the Badain Jaran Desert of western China. A field study for the local water cycle of a lake-desert system was conducted near the Noertu Lake in the Badain Jaran Desert from 21 June to 26 August 2008. An underground wet sand layer was observed at a depth of 20–50 cm through analysis of datasets collected during the field experiment. Measurements unveiled that the near surface air humidity increased in the nighttime. The sensible and latent heat fluxes were equivalent at a site about 50 m away from the Noertu Lake during the daytime, with mean values of 134.4 and 105.9 W/m2 respectively. The sensible heat flux was dominant at a site about 500 m away from the Noertu Lake, with a mean of 187.7 W/m2, and a mean latent heat flux of only 26.7 W/m2. There were no apparent differences for the land surface energy budget at the two sites during the night time. The latent heat flux was always negative with a mean value of –12.7 W/m2, and the sensible heat flux was either positive or negative with a mean value of 5.10 W/m2. A portion of the local precipitation was evaporated into the air and the top-layer of sand dried quickly after every rainfall event, while another portion seeped deep and was trapped by the underground wet sand layer, and supplied water for surface psammophyte growth. With an increase of air humidity and the occurrence of negative latent heat flux or water vapor condensation around the Noertu Lake during the nighttime, we postulated that the vapor was transported and condensed at the lakeward sand surface, and provided supplemental underground sand pore water. There were links between the local water cycle, underground wet sand layer, psammophyte growth and landscape evolution of the mega-dunes surrounding the lakes in the Badain Jaran Desert of western China.     

Contents and spatial distribution patterns of heavy metals in the hinterland of the Tengger Desert,China

The desert in northern China is one of important sources of loess and one significant source of material for sandstorms in Asia. The sand/dust that is transported from desert when sandstorms occur can destroy the growth of crops, cause serious losses and great harm to the economic construction and life safety, and cause natural environment pollution. Hence, it is very important to deepen the research into heavy metals in surface deposits at vulnerable ecological region of arid land of northern China to guide local industrial and agricultural development and improve environmental protection. In this research, 10 heavy metal elements (Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb, and Th) were tested and analyzed in 33 soil sample sites collected from the hinterland of the Tengger Desert, northern China. The results showed that the average abundance of Th exceeded its background soil value of China by more than 5.2 times, which suggests that the Tengger Desert is polluted by Th. In addition, based on principal component analysis, spatial differentiation, and correlation analysis, we identified the source of element with a coefficient of variation in abundance of greater than 0.5 or exceeding the background soil value of China. Principal component analysis and correlation analysis showed that the sources of heavy metals of Cr, Mn, Fe, Co, Ni, Cu, and Cd were similar, while those of Th and Zn were different. Moreover, based on the contents and spatial distribution characteristics of those heavy metal elements, we found that the formation of heavy metal elements enrichment areas is caused by industrial pollution, development of irrigated agricultural, geological, and geomorphic conditions, and the sedimentary environment in the study area. Our result can provide information on the environmental background values of soils in the hinterland of the Tengger Desert. Background value of China^a(mg/kg)