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61.
CONCLUSION The analysis of air parcel trajectories affecting Shanghai indicates that the coming-direction of air parcel is different
in various months. The transport track of trajectory (backward and forward) is closely related to the synoptic system, and
also related to acid rain occurring in Shanghai region.
Air pollution and acid rain in Shanghai region have relationship with both the influence of local pollutants and the influence
of external pollutants from southwest and northeast. 相似文献
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Xiaoping Du Huadong Guo Xiangtao Fan Junjie Zhu Zhenzhen Yan Qin Zhan 《International Journal of Digital Earth》2016,9(3):252-271
The frequency of coastal flood damages is expected to increase significantly during the twenty-first century as sea level rises in the coastal floodplain. Coastal digital elevation model (DEM) data describing coastal topography are essential for assessing future flood-related damages and understanding the impacts of sea-level rise. The Shuttle Radar Topography Mission (SRTM) and Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM) are currently the most accurate and freely available DEM data. However, an accuracy assessment specifically targeted at DEMs over low elevation coastal plains is lacking. The present study focuses on these areas to assess the vertical accuracy of SRTM and ASTER GDEM using Ice, Cloud, and land Elevation Satellite, Geoscience Laser Altimeter System (ICESat/GLAS) and Real Time Kinematic (RTK) Global Positioning System (GPS) field survey data. The findings show that DEM accuracy is much better than the mission specifications over coastal plains. In addition, optical remote sensing image analysis further reveals the relationship between DEM vertical accuracy and land cover in these areas. This study provides a systematic approach to assess the accuracy of DEMs in coastal zones, and the results highlight the limitations and potential of these DEMs in coastal applications. 相似文献
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梅山组海底扇作为中央峡谷水道之外最引人注目的大型储集体,是琼东南盆地尤其是深水区常规碎屑岩领域下一步最为重要的勘探对象。总结了琼东南盆地各凹陷钻井资料所揭示的梅山组海底扇差异分布现象,通过研究区大陆架发育特征、陆架坡折带发育特征,结合物源供给与优势海流方向,首次从宏观格局解释了琼东南盆地中央坳陷带不同凹陷海底扇发育地质背景的差异及成因,提出乐东凹陷梅山组大型海底扇主物源来自东北方向海南隆起。通过细化中中新世大海退内部次级海平面旋回特征,首次建立了本区梅山组层序充填与海平面旋回的精确对应关系,从层序成因角度厘清了梅山组各期次海底扇发育演化特征与凹陷级别的有利储层展布特征,并据此提出相应的勘探建议,指出乐东凹陷梅山组中—晚期海底扇储层风险低,是梅山组海底扇领域突破的首选区带;陵水凹陷早期海底扇圈闭有效性较好,是梅山组海底扇大规模成藏的有利勘探方向。该研究为梅山组海底扇领域的勘探部署提供了新思路。 相似文献
66.
基于地面观测的遥感监测蒸散量验证方法研究 总被引:1,自引:2,他引:1
为了保证遥感监测蒸散量的准确性,需建立一套较完整的遥感监测蒸散量地面验证方法对其进行验证.通过由大孔径闪烁仪、涡动相关仪和自动气象站等组成的蒸散量观测系统可以获取不同卫星像元尺度蒸散量的地面观测值.自2002年以来,由海河流域的密云、馆陶、大兴及小汤山等站构建了一个不同卫星像元尺度蒸散量的观测站网,经过严格的观测数据处理与质量控制,获取了一大批卫星像元尺度蒸散量及其配套参数的地面观测值.同时,建立了一套基于地面观测的遥感监测蒸散量验证流程,重点对验证像元的选取以及评价指标的构建等进行探讨.依据上述验证流程,在海河流域的北京地区开展了遥感监测蒸散量的地面验证工作.利用2008年密云站和大兴站的大孔径闪烁仪观测数据,对基于MODIS数据估算的北京地区区域蒸散量进行验证.结果表明:这套基于大孔径闪烁仪观测数据的遥感监测蒸散量验证方法是合理、可行的.其中2008年北京地区遥感监测月、日蒸散量的均方差分别为13.75和0.91 mm,平均相对误差分别为22.79%、18.61%. 相似文献
67.
青岛近海冬末春初海水碳酸盐体系的特征 总被引:1,自引:0,他引:1
通过在青岛近岸海域采集海水样品,测定了海水pH、总碱度(TA)、溶解无机碳(DIC)以及溶解钙离子,并根据这些参数计算了海水中的碳酸氢根、碳酸根等分量以及海水二氧化碳分压(pCO_2)、碳酸钙饱和度等参数。各站点海水pH范围为8.09~8.18,平均8.13;TA范围为2309~2345(mol/kg,平均2325(mol/kg;DIC范围为2158~2200(mol/kg,平均2180(mol/kg;海水中溶解钙离子的浓度为0.3700~0.3732g/kg,平均0.3716g/kg。求得海水pCO_2范围为371~476(atm,平均415(atm;方解石和文石的饱和度范围分别为2.31~2.84和1.45~1.78,平均值分别为2.57和1.61。通过与温度、盐度进行比较,发现冬末春初青岛近岸海域海水总碱度、溶解无机碳和溶解钙离子具有较为均匀的特征,是冬季混合导致的结果。海水pH有一定的变化性,与营养盐和叶绿素a的关系显示,观测区西部已开始增强的生物生产使海水pH升高,pH是该季节影响海水pCO_2、碳酸钙饱和度等参数的主要因素。该季节青岛近海总体上表现为大气CO_2的弱源,但西部海区是大气CO_2的弱汇。 相似文献
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The internal transcribed spacer regions (ITS1 and ITS2) and 5.8S rRNA genes were sequenced in six populations of four Aspidisca species, namely A. leptaspis, A. orthopogon, A. magna and A. aculeata. Phylogenetic trees were constructed by means of Bayesian inference (BI), Maximum Parsimony (MP), Neighbor-Joining (NJ),
and Maximum Likelihood (ML) to assess the inter- and intra-species relationships within the genus Aspidisca. All trees show similar topologies with stable supports and indicate that: (1) four well known groups, i.e., Oligotrichia,
Stichotrichia, Choreotrichia and Hypotrichia, are distinctly outlined within the class Spirotrichea, and all are monophyletic
other than Hypotrichia; (2) members of Aspidisca can be distinguished well, based on the ITS1-5.8S-ITS2 region sequences, and A. leptaspis and A. magna shared a closer relationship than other species; (3) Aspidisca and Euplotes branch early in the subclass Hypotrichia. To compare the phylogenetic relationships based on different genes, SSU rRNA trees
were also constructed with nearly the same species inclusion, which revealed different topologies of inter-species, inter-genera
and inter-subclasses. 相似文献
70.