Atmospheric pollution assessment near potential source of natural aerosols in the South Gobi Desert region,China     

Mikalai Filonchyk  Volha Hurynovich  Shuwen Yang 《地理信息系统科学与遥感》2020,57(2):227-244

ABSTRACT

Rapid economic growth, a high degree of urbanization and the proximity of a large number of desert and semidesert landscapes can have a significant impact on the atmosphere of adjacent territories, leading to high levels of atmospheric pollution. Therefore, identifying possible sources of atmospheric pollution is one of the main tasks. In this study, we carried out an analysis of spatial and temporal characteristics of five main atmospheric pollutants (PM_2.5, PM₁₀, SO₂, NO₂, and CO) near potential source of natural aerosols, affecting seven cities (Wuhai, Alashan, Wuzhong, Zhongwei, Wuwei, Jinchang, Zhangye), located in immediate proximity to the South Gobi deserts. The results, obtained for the period from 1 January 2016 to 31 December 2018, demonstrate total concentrations of PM_2.5 and PM₁₀ are 38.2 ± 19.5 and 101 ± 80.7 μg/m³ exceeding the same established by the Chinese National Ambient Air Quality Standard (CNAAQS), being 35 and 70 μg/m³, respectively. Based on the data from Moderate Resolution Imaging Spectroradiometer (MODIS) for the whole period, Clean Сontinental (71.49%) and Mixed (22.29%) types of aerosols prevail in the region. In the spring and winter seasons maximum concentrations of pollutants and high values of Aerosol Optical Depth (AOD) in the region atmosphere are observed. PM_2.5 and PM₁₀ ratio shows the presence of coarse aerosols in the total content with value 0.43. The highest concentrations of pollutants were in the period of dust storms activity, when PM_2.5 and PM₁₀ content exceeded 200 and 1000 µg/m³, and AOD value exceeded 1. UV Aerosol Index (UVAI), Aerosol Absorbing Optical Depth (AAOD), and Single Scattering Albedo (SSA), obtained from Ozone Monitoring Instrument (OMI), demonstrate the high content of dust aerosols in the period of sandstorms. Analysis of backward trajectories shows that dust air masses moved from North to Northwest China, affecting large deserts such as Taklamakan, Gurbantunggut, Badain Jaran, Tengger, and Ulan Buh deserts.  相似文献   

古尔班通古特沙漠大气边界层参数化方案的模拟评估[1]     

王豫  阿吉古丽·沙依提  买买提艾力·买买提依明  周成龙  高佳程 《沙漠与绿洲气象(新疆气象)》2020,14(4):78-87

为准确描述我国最大的固定/半固定沙漠-古尔班通古特沙漠区域的大气边界层结构，本文利用该沙漠腹地2017年的梯度铁塔和通量观测数据，基于中尺度气象模式WRF (Weather Research and Forecast v3.7.1)，分析了5种边界层参数化方案在古尔班通古特沙漠的适用性。结果表明：1）采用WRF模拟沙漠腹地近地层内的边界层特征时，2m气温的模拟存在冷偏差，5种边界层参数化方案均能较好地模拟出四个季节2m气温的日变化特征，其中非局地方案ACM2(Asymmetric Convective Model version 2)对2m气温效果最好，局地方案BL方案的模拟偏差最大；2）5种边界层参数化方案均能够模拟出10m风速的日变化特征，其中局地方案BL(Bougeault-Lacarrere)对10m风速效果最佳；3）采用WRF模拟沙漠近地层内的地表通量特征时，感热通量存在高估现象，潜热通量存在低估现象，5种边界层参数化方案均能较好地模拟出四个季节模拟时间段内地表净辐射通量的日变化特征，其中局地方案MYJ(Mellor-Yamada-Janjie)的模拟精度最高。  相似文献   

古尔班通古特沙漠南部沙垄水分动态--兼论积雪融化和冻土变化对沙丘水分分异作用     

王雪芹  张元明  蒋进  陈均杰  宋春武 《冰川冻土》2006,28(2):262-268

2004年3月至2005年7月对古尔班通古特沙漠南部典型半固定沙垄土壤水分进行了系统监测,结合气象资料,特别是对冬季积雪和冻土资料的分析,认为该沙漠沙丘土壤水分时空变化规律在很大程度上受积雪融化和季节性冻土的影响.由于冬季稳定存在20~30 cm的积雪于春季融化,使得春季沙丘土壤含水率成为全年最高的季节,从而为早春植物的萌发生长创造了有利的条件.冬季1 m多深的冻土于早春时节由表及里开始消融,沙丘表面融化的雪水在坡面重力作用下,沿难以透水的冻土层上界自坡上向坡下发生迁移,在春夏季形成了垄间最高、坡部次之和垄顶最少的土壤水分空间格局.该研究具有生态学意义,可为古尔班通古特沙漠特殊环境条件下植被恢复与重建提供依据.  相似文献   

Geology and rare-earth element geochemistry of highly evolved, molybdenite-bearing granitic plutons, Southeastern Desert, Egypt     

Gehad M. Saleh 《中国地球化学学报》2007,26(4):333-344

The field relations, mineralogy, and major and trace elements (including REE analyses of whole-rock samples and minerals) of granites and their associated molybdenite uranium mineralized aplites in Southeastern Desert, Egypt, have been studied. The granites are leucocratic and mostly peraluminous in nature with muscovite increasing at the expense of biotite. The chemical and mineralogical characteristics of the granitic rocks indicate that their melts originated from the LILE-enriched mantle wedge by partial melting and are contaminated by crustal melts, followed by thermogravitational processes. Leucogranites with higher Na2O/K2O ratios from Um Dargag and Um Maiat crystallized under H2O-saturated equilibrium conditions in which the exsolved vapor continuously migrated away. The REE patterns of the granites studied are characterized by LREE enrichments and negative Eu anomalies. In comparison, the potassic aplites and the more sodic leucogranites are depleted in LREE, enriched in HREE and show more remarkable negative Eu anomalies. Allanite and monazite are the most important REE carriers in the granites. These minerals are strongly enriched in LREE, whereas fluorite and xenotime, which are more abundant in the aplites, are enriched in HREE. The average Lu/Ce ratio represents the fractionation trend with respect to HREE. It is 0.71 for radioactive fluorite, and it increases to 1.22 for non-radioactive fluorite. The high REE contents of molybdenite represent re-deposition of the mobilized Mo and REE. Due to the strong control of accessory minerals, the REEs are of limited use in petrogenetic modelling of highly evolved granitic systems.  相似文献   

塔克拉玛干沙漠腹地沙尘暴发生条件分析   总被引：4，自引：0，他引：4       下载免费PDF全文

李生宇雷加强  徐新文 《应用气象学报》2007,18(4):490-496

利用塔中气象站1997—2002年的气象资料, 从沙尘源丰富程度、风动力条件和空气稳定度等方面分析了塔克拉玛干沙漠腹地沙尘暴的成因。结果表明:在塔克拉玛干沙漠腹地, 沙尘源极为丰富, 为沙尘暴发生提供了必要条件, 降水基本不能改变沙面的湿润状况, 沙尘源丰富度不是沙尘暴发生的限制因子; 风动力是沙尘暴发生的重要条件, 而月平均风速和大风日数是风动力的重要定量表征指标; 空气稳定性也是沙尘暴发生的重要条件, 温度和天气过程是其重要标志, 沙尘暴发生与温度呈正相关, 沙尘暴多发生在夏季和午后; 降水是沙漠腹地天气过程的重要指标, 月降水日数和降水总量与沙尘暴日数呈正相关; 20世纪90年代以来沙尘暴逐年减少, 这种变化趋势可能与全球气候变化有关。  相似文献   

塔克拉玛干沙漠石油公路沿线风沙活动的气候环境   总被引：5，自引：2，他引：3  

温向乐  韩致文 《中国沙漠》1998,18(1):77-80

塔克拉玛干沙漠石油公路沿线风沙活动是由塔木盆地内热能释放与冷空气入侵相互作用的结果。冷期,盆地内冷高压逆温作用较强,地面热能不足,使得风力和风沙活动强度弱;暖期,盆地内热源剧增,每当热能源饱和遇到冷空气入侵诱导,导致了强风及强风沙活动天气。可见,区内风沙活动及风成景观的塑造过程,主要是在暖干期进行的。  相似文献   

Processes of the deposition and vicissitude of Mu Us Desert, China since 150 ka B.P.   总被引：1，自引：0，他引：1  

Li Baosheng  Jin Heling  Lü Haiyan  Zhu Yizhi  Dong Guangrong  Sun Donghuai  Zhang Jiashen  Gao Quanzhou  Yan Mancun 《中国科学D辑(英文版)》1998,41(3):248-254

“Milanggouwan stratigraphical section” named lately takes down 27 cycles of alternately evolutionary histories of desert depositions in the Mu Us area with the fluviolacustrine facies and palaeosols since 150 ka B. P. Studies show that the sedimentary form was induced by the growth and decline and confrontation each other between the winter monsoon and the summer monsoon of East Asia in the past 150 ka. Project supported by the National Natural Science Foundation of China (Grant No. 49473192).  相似文献   

Rain infiltration and crust formation in the extreme arid zone of the Atacama Desert, Chile     

Wanda L. Davis  Imke de Pater 《Planetary and Space Science》2010,58(4):616-1991

A key question in understanding life on Mars under dry(ing) conditions is how arid soils respond to small levels of liquid water. We have conducted a series of simulated rain experiments in the hyperarid core region of the Atacama Desert. Rain amounts from 0.24 to 3.55 mm were applied in the early evening to the soil. We conclude that rain events of less than 1 mm do not saturate the surface, and the soil humidity at the surface remains below 100%. Rain events of 2 mm or more generate free water in the pore space of the soil surface, which may be necessary to support biological activity in the soil. The crust on the surface of the soil is a strong barrier to the diffusion of subsurface moisture and subsequent evaporation. Our results show that once the relative humidity in hyperarid soils begins to fall below 100% the rate of decrease is quite rapid. Thus, the precise value assumed for the limits of life or water activity, do not appreciably change the time of water availability resulting from small desert rains. The Atacama Desert results may be applied to models of (H₂O) wetting in the upper soils of Mars due to light rains, melting snow and heavy precipitating fog.  相似文献   

古尔班通古特沙漠植物雾凇凝结特征   总被引：1，自引：0，他引：1       下载免费PDF全文

周宏飞  周宝佳  代琼 《水科学进展》2010,21(1):56-62

古尔班通古特沙漠冬季稳定积雪期长,多雾凇天气.通过2007年11月~2008年3月在沙漠南缘的定位实验观测,发现植物雾凇凝结水总量平均为5.8 mm,占冬季降水量的21.8%,其中,沙漠区垄间和垄上植物雾凇凝结水总量分别是3.8 mm和9.1 mm,各占冬季降水量的14.4%和34.3%;植物雾凇凝结水量是雪面凝结水量的5倍;荒漠植物的雾凇凝结水可以增加古尔班通古特沙漠冬季植被分布区域水资源量.雾凇形成的最大风速一般小于3m/s;-15℃~-20℃是雾凇形成次数最多的气温区间,占全部雾凇日数的24.3%,气温低于-30℃时雾凇凝结量显著减少;观测期雾凇形成时大气最大相对湿度小于80%的日数占冬季雾凇日数的41%.低温、高湿、低风速的气象条件,加之梭梭枝条的细直径和针状叶特征,是古尔班通古特沙漠冬季具有丰富植物雾凇凝结水的重要原因.  相似文献   

毛乌素沙地南缘固沙灌丛下地表凝结水特征     

陈晓涵  吴永胜  海春兴 《中国沙漠》2023,43(1):83-95

尽管凝结水在干旱生态系统中所发挥的重要作用已被广泛关注,但对其在固沙灌丛下时空变化特征的研究仍然比较薄弱。为探明固沙灌丛对地表凝结水的影响,在毛乌素沙地南缘沙区选择3种典型固沙灌丛（沙柳Salix psammophila、柠条Caragana korshinskii和油蒿Artemisia ordosica）,以无固沙灌丛影响的裸沙作为对照,用微型蒸渗仪测定了固沙灌丛下不同位置（根部、1/2冠幅和外缘）和不同方向（东、南、西、北）上地表凝结水的形成和蒸发特征。结果表明：（1）与对照相比,固沙灌丛的存在显著降低了地表凝结水量,沙柳、油蒿和柠条灌丛下凝结水量分别降低了29%、32%和33%;(2)不同类型固沙灌丛下地表凝结水量由里向外均呈显著增加的趋势,但不同方向上地表凝结水量差异不显著;（3）固沙灌丛的存在减缓了凝结水的形成和蒸发过程,即凝结水自19:00开始形成,到次日08:00基本结束,至13:00—15:00蒸发殆尽,其形成过程整体上表现出增加—平缓—增加的趋势,柠条和油蒿灌丛下地表凝结水在03:00—05:00甚至有少量蒸发,而蒸发过程呈稳定下降趋势;（4）凝结水的形成过程与空气...  相似文献