The variation characteristics and effect factors of surface ozone concentration in the Taklimakan Desert hinterland     

XinChun Liu  YuTing Zhong  Qing He  YanMei Peng  XingHua Yang  Ali Mamtimin  Wen Huo 《寒旱区科学》2014,6(1):0081-0088

Based on automatic continuous surface ozone concentration observation data from June 10, 2010 to March 20, 2012 in the Taklimakan Desert hinterland, combined with corresponding meteorological data, the temporal, seasonal and daily variation characteristics of surface ozone concentrations under different weather conditions were analyzed. At the same time, the main fac- tors affecting ozone variation are discussed. Results show that： （1） Daily variation of ozone concentration was characterized by one obvious peak, with gentle changes during the night and dramatic changes during the day. The lowest concentration was at 09：00 and the highest was at 18：00. Compared to urban areas, there was a slight time delay. （2） Ozone concentration variation had a weekend effect phenomenon. Weekly variation of ozone concentration decreased from Monday to Wednesday with the lowest in Wednesday, and increased after Thursday with the highest in Sunday. （3） The highest monthly average concentration was 89.6 I.tg/m3 in June 2010, and the lowest was 32.0 ~g/m3 in January 2012. Ozone concentration reduced month by month from June to December in 2010. （4） Ozone concentration in spring and summer was higher than in autumn and winter. The variation trend agreed with those in other large and medium-sized cities. （5） Under four different types of weather, daily ozone concentration var- ied most dramatically in sunny days, followed by slight variation in rain days, and varied gently in cloudy days. Ozone concentra- tion varied inconspicuously before a sandstorm appearance, and dropped rapidly at the onset of a sandstorm. （6） Daily variation of radiation was also characterized by a single peak, and the variation was significantly earlier than ozone concentration variation. Sun radiation intensity had a direct influence on the photochemical reaction speed, leading to variation of ozone concentration. （7） Daily average ozone concentration in dust weather was higher than in slight rain and clear days. The variation of near surface ozone concentration could also be affected by meteorological factors such as relative humidity, wind speed, wind direction and sunshine hours. Thus, numerous factors working together led to ozone pollution.  相似文献   

Impact of dust aerosol on glacial-interglacial climate     

刘玉芝  石广玉  谢永坤 《大气科学进展》2013,30(6):1725-1731

The temperature anomaly and dust concentrations recorded from central Antarctic ice core records display a strong negative correlation. The dust concentration recorded from an ice core in central Antarctica is 50-70 times higher during glacial periods than interglacial periods. This study investigated the impact of dust aerosol on glacial-interglacial climate, using a zonal energy balance model and dust concentration data from an Antarctica ice core. Two important effects of dust, the direct radiative effect and dust-albedo feedback, were considered. On the one hand, the direct radiative effect of dust significantly cooled the climate during the glacial period, with cooling during the last glacial maximum being as much as 2.05℃ in Antarctica. On the other hand, dust deposition onto the ice decreased the surface albedo over Antarctica, leading to increased absorption of solar radiation, inducing a positive feedback that warmed the region by as much as about 0.9℃ during the glacial period. However, cooling by the direct dust effect was found to be the controlling effect for the glacial climate and may be the major influence on the strong negative correlation between temperature and dust concentration during glacial periods.  相似文献   

Particle-size analysis of aeolian dusts,soils and sediments in very small quantities using a Coulter Multisizer     

G. H. McTainsh  A. W. Lynch  R. Hales 《地球表面变化过程与地形》1997,22(13):1207-1216

The Coulter Multisizer has clearly defined strengths and weaknesses as a particle-sizing instrument. It is easier to operate than its Coulter predecessors, though less so than several of its competitors. The Multisizer is best suited to handle very small samples with a narrow particle-size range, such as aeolian dusts and other sediments available only in small quantities. For such samples, Multisizer analysis times are short, resolution is very high (256 size classes) and reproducibility is good. The Multisizer is less well suited to soils and other samples available in large quantities and with a broad particle-size range. For soil particle-size analyses a composite method is proposed involving: Multisizer (2–75 μm), Pipette (<2 μm) and Sieve (>75 μm). © 1997 John Wiley & Sons, Ltd.  相似文献   

Dust source of the Holocene loess-soil and pedogenic environmental changes in the upper Huaihe River     

LI Xinyan  HUANG Chunchang  PANG Jiangli  HE Zhong 《地理学报》2009,19(1):107-117

Based on field surveys, soil samples were collected at the YPC site, Yuzhou City, Henan Province for analysis of contents of major and trace elements and their variations with XRF and comparison with the curves of magnetic susceptibility, pH value distribution, loss on ignition and particle-size distribution. It was concluded that the dust source of loess in the upper reaches of the Huaihe River Basin was different from that in the Loess Plateau. And the Holocene pedogenic environmental changes in the upper reaches of the Huaihe River Basin were revealed.  相似文献   

Evaluation of a wind erosion model in a desert area of northern Asia by eddy covariance     

Gerardo Fratini  Monia Santini  Paolo Ciccioli  Riccardo Valentini 《地球表面变化过程与地形》2009,34(13):1743-1757

For the first time, vertical fluxes of mineral dust measured by Eddy Covariance in two desert sites of Northern Asia have been used to test the performances of a wind erosion model in the field. Soil parameters required by the model were obtained through field and laboratory determinations. Model predictions and direct measurements have been compared. The main finding was that the direction of the horizontal wind relative to the orientation of nebkhas played a crucial role in determining the emission of particles in one of the investigated sites. Being unable to simulate such interaction, the model generally overestimated the actual emission. It provided, instead, reliable predictions (r² = 0·87) when the wind direction was suitable in detaching loose erodible elements placed on nebkhas thanks to their normal orientation. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

福建长乐东部海岸沙丘发育成因及特征   总被引：2，自引：0，他引：2  

刘建辉  郭占荣 《福建地质》2006,25(4):185-191

通过对长乐东部沿海海岸沙丘的形成及其发育成因进行分析,认为风况、沙源和地形空间是形成该地区海岸沙丘的基本条件。另外,根据沙丘的空间组合、形态特征、地貌特点等,对该地区的海岸沙丘分布形态进行了进一步的分类阐述。  相似文献   

晚第四纪以来中纬度北太平洋古生产力记录     

吴枫  安芷生  曹军骥 《海洋地质与第四纪地质》2004,24(3):83-89

综合论述了晚第四纪以来北太平洋中纬度地区海洋古生产力变化特征及其影响因素。晚第四纪以来,北太平洋中纬度地区海洋古生产力变化表现出明显的冰期-间冰期尺度波动特征,冰期条件下海洋古生产力增加,而间冰期条件下古生产力较低。在综合考虑影响北太平洋古生产力变化的各种因素后,初步认为：冰期气候条件下,亚洲粉尘携带的浮游生物生长所必需养分的增加促进了浮游生物的生长,可能是导致本区冰期时古生产力增加的主要原因。  相似文献   

蒙古西北部Tolbo湖沉积物粒度敏感组分记录的全新世风沙活动     

张延利  毛春晖  张家武  黄小忠  OtgonbayarDemberel 《湖泊科学》2023,35(1):368-380

作为全球主要的粉尘源区之一,亚洲中部干旱区全新世环境变化备受关注,但目前仍缺乏连续的风成沉积记录。本文利用蒙古西北部Tolbo湖岩芯（TB19-A,332 cm）沉积物,在AMS14C定年和粒度分析基础上,采用对数正态分布函数拟合及粒级-标准偏差相结合的方法分离出沉积物中风成组分以重建区域风沙活动历史。结果显示,Tolbo湖沉积物中值粒径为15～84μm和大于84μm的组分分别是区域尘暴和局地风沙活动的良好指标。蒙古西北部地区末次冰消期晚期（13.75 11.6 cal ka BP）,Tolbo湖流域内有较强的局地风沙活动,可能与YD寒冷事件有关。全新世以来,流域内局地风沙活动与蒙古西北部区域尘暴活动的变化具有一致性,具体表现为：早中全新世风沙活动总体较弱,其中9.7 8.6 cal ka BP和7 6 cal ka BP为区域尘暴较强时段;5 cal ka BP之后局地风沙活动与区域尘暴强度显著增加,直至0.7 cal ka BP两者均维持在较高水平;0.3 cal ka BP以来区域尘暴活动再次增强。蒙古西北部与中国北方公海、博斯腾湖记录的尘暴历史具有一致的变化趋势,反映了与西伯利...  相似文献   

Decoupling of Aerosol Absorption Coefficient in the Spring of 2006 at an Urban Site in Beijing     

Pan Xiaole  Yan Peng  Tang Jie 《气候变化研究进展》2008,4(00):37-41

 A statistic regression approach was used to estimate the wavelength exponents of black carbon (BC) and dust particles, and further to separate the contributions of the two types of aerosols to the total light absorption coefficient measured in the Beijing urban area in the spring of 2006. The results show that the wavelength exponent (a) of black carbon aerosol at urban site was approximately -0.92, which is in agreement with the value of -0.8±0.2 reported in related studies. The decoupling analysis of the measured light absorption coefficients during the three floating dust periods ( March 25, March 27, and April 9) demonstrates that, on average, the light absorption caused by dust particles took up about 32.8% of the total light absorption at 520 nm wavelength, and by black aerosol more than 60%. This indicates that the black carbon was still the major contributor to the total aerosol light absorption in Beijing urban area even during the floating dust periods.  相似文献   

内蒙古中西部地面感热通量影响沙尘暴的观测分析   总被引：9，自引：7，他引：2  

李彰俊  孙照渤  姜学恭  马瑞芳 《中国沙漠》2008,28(3):537-543

利用内蒙古中西部不同地表类型的16个测站2005—2006年3—5月逐小时地面观测资料和逐日沙尘暴资料,计算了地面感热通量、地面位温并分析它们与沙尘暴的关系,结果发现:在内蒙古中西部春季地面感热通量表现为净加热,且沙尘暴发生次数多的年份净地面感热加热强度反而较小。在沙尘暴发生前,沙漠区和高平原区地面感热通量达到最大,而丘陵和平原地区反而开始降低。对于沙尘暴发生前12 h累积的地面感热加热强度及导致的地面位温上升幅度,高平原和丘陵平原区要强于沙漠区。但相对而言,沙漠和高平原地区地面感热加热影响沙尘暴的“效率”更高。  相似文献