对流层污染测量仪(MOPITT)原理及其应用     

马立杰  黄海军  龚建明  崔迎春  张志珣 《海洋科学》2006,30(2):81-84

1对流层污染测量仪（MOPITT）概况 MOPITT（the Measurement of Pollution in the Troposphere）测量仪搭载在美国地球观测计划（EOS）Terra卫星上,该卫星于1999年12月18日成功发射。Terra卫星采用高度为705km,太阳同步轨道,地方时上午10：30通过赤道,3d对整个地球观测一遍。根据气体相关放射性测量学原理,MOPITT测量对流层的CO浓度（体积混合率）和总柱CO和CH6含量（卫星与地球之间一个大气柱里单位面积分子总数）。  相似文献   

建筑结构震害预测方法研究与实践     

赵少伟  窦远明  张书祥  张会乔 《地震工程与工程振动》2006,26(3):51-53

建筑结构在地震中的损坏程度是人员伤亡和经济损失预测的基础,也是城市地震经济损失的主要组成部分。本文结合某中等城市市区六种典型建筑在地震作用下的受力特点和破坏机理,分别采用了相应的易损性分析方法,建立了市区震害矩阵。预测结果真实可靠,为进一步进行抗震规划和统计震害损失提供依据。  相似文献   

琼北玄武岩建造区域岩石—土壤体系化学元素垂向分布规律     

付燕刚  蔡永文  马生明  唐世新  林建绥  胡树起  苏磊  高健翁  龚晶晶  杨剑洲  王振亮  段壮  郝泽江  林鲁军  赵克强  李勇 《地质论评》2024,70(3):2024030002-2024030002

土壤由岩石风化而来,岩石—土壤是一个密切联系的体系,是地球系统科学中与人类关系最为密切的一部分。为调查研究地质建造单元岩石—土壤体系（简称：岩土体系）中的物质组成演化特征,我们必须选择原地风化的残积物出露区域来完成土壤垂向剖面采样。本文以海南岛区域生态地质背景调查项目的资料数据为基础,科学阐述了残积物剖面的确定方法,并依据琼北玄武岩垂向剖面地球化学数据,总结出如下结论：垂向剖面SiO2含量呈现出土壤表层A层和岩石的高,土壤B、C层含量低的“凹”字型特征,与Al2O3含量变化趋势相反（“凸”字型）,两个代表性组分存在明显的负相关性,其他组分根据其亲和性,与该两种组分协同变化,部分受表层活动影响较大的元素,例如有机质、I等部分微量元素,则不具有该规律,土壤表层（A、B层）与深层（C层）、岩石中差别通常较大。  相似文献   

下一代深海装备用高强度陶瓷材料及结构分析          下载免费PDF全文

龚文  吴超峰  赵治平  邵成 《数字海洋与水下攻防》2020,3(4):281-287

深海装备在服役过程中需要抵抗海水及应力腐蚀,承受载荷对结构的考验及深海环境的高压强, 这对材料的综合性能提出了巨大挑战。以氧化铝为代表的高强度陶瓷材料具有耐腐蚀、质量轻、高强度等特点,在深海装备应用中具有巨大潜力。对多种高强度陶瓷材料进行了分析比较,并针对深海应用的要求讨论了材料选型和缺陷要求,为下一代深海装备材料的发展提供了参考。  相似文献   

Spatial variation of abundant picoeukaryotes in the subtropical Kuroshio Current in winter     

Ya-Fan Chan  Chih-Ching Chung  Gwo-Ching Gong  Ching-Wei Hsu 《Marine Ecology》2020,41(1):e12579

To understand the importance of picoeukaryotes in the biogeochemical cycle in the subtropical Kuroshio Current, a year-round survey of the hydrography and the distribution of picoeukaryotes were conducted in four oceanographic cruises from October 2012 to July 2013. In comparison with other seasons, the highest abundancy of photosynthetic picoeukaryotes, with concentrations >10⁴ cells/ml, was observed around the eastern boundary of the Kuroshio in the winter. Accordingly, the composition of picoeukaryotes in this cold season was further studied by a metabarcoding analysis of the 18S rRNA gene. The majority of picoeukaryotes comprised Alveolata, followed by Haptophyta and Stramenopiles. Their composition was diverse in the waters affected by the Kuroshio and in the offshore province. For Haptophyta, in contrast to clade A prevailing in the Kuroshio waters, clade B1, which was considered the host of uncultivated diazotrophic cyanobacterium group A (UCYN-A), appeared only in the offshore area. Similarly, in Stramenopiles, Pseudo-nitzschia spp. and MAST-1D, respectively, dominated in the Kuroshio-influenced and offshore areas. While Alveolata was the most abundant group, the distributions of all lineages were similar. The association between picoeukaryote succession and hydrographic change is yet to be fully understood. Our results will assist future studies on the community composition of picoplankton and their relationship with marine ecology in the region.  相似文献   

生物土壤结皮对温带荒漠植物凋落物分解的影响   总被引：1，自引：1，他引：0  

张瑞  周晓兵  张元明 《中国沙漠》2019,39(6):151-158

环境和微生物群落的变化会影响凋落物的分解过程。生物土壤结皮是干旱荒漠区地表普遍存在的生物覆盖,对土壤物理化学性质有显著影响,但对于是否影响荒漠植物凋落物分解缺乏深入了解。选择8种在古尔班通古特沙漠广泛分布的荒漠植物（白梭梭Haloxylon persicum、梭梭Haloxylon ammondendron、黑沙蒿Artemisia ordosica、粉苞菊Chondrilla piptocoma、羽毛针禾Aristida pennata、刺沙蓬Salsola ruthenica、紫翅猪毛菜Salsola affinis、钩刺雾冰藜Bassia hyssopifolia）,分析生物土壤结皮覆盖对这8种凋落物质量损失率和分解速率的影响。结果表明：生物土壤结皮和植物种对凋落物质量损失率有极显著影响（P<0.01）,生物土壤结皮的存在增大了荒漠植物凋落物质量损失率,不同物种的分解率差异显著。8种植物凋落物的质量损失率在结皮覆盖条件下为13.67%~64.56%,去除结皮处理下为13.58%~54.13%。其中,结皮覆盖条件下白梭梭、梭梭、紫翅猪毛菜的质量损失率（46.12%、41.26%、64.56%）显著高于去除结皮处理（35.85%、36.97%、54.13%,P<0.05）。生物土壤结皮的存在缩短了凋落物的半分解和95%分解时间,缩短长度随物种差异而不同,受凋落物的初始全碳和全氮含量调节。荒漠地表生物土壤结皮对植物凋落物分解具有促进作用,且这种作用具有显著的种间差异,地表生物土壤结皮的存在对初始全碳含量较低而全氮含量较高的凋落物促进作用更明显。  相似文献   

植被盖度对沙丘风沙流结构及风蚀量的影响   总被引：4，自引：2，他引：2  

余沛东  陈银萍  李玉强  闫志强  王旭洋  牛亚毅  龚相文 《中国沙漠》2019,39(5):29-36

以科尔沁沙地不同植被盖度沙丘为研究对象,采用野外可移动风洞进行原位测试,开展了沙丘植被盖度对风沙流输沙率影响的研究,探讨了地表风蚀量与风速及植被盖度的关系。结果表明：空气动力学粗糙度随植被盖度增加先平缓后剧烈,与植被盖度相关关系呈三次函数增长。在各植被盖度下各层输沙率均随高度增加而递减,随风速增加而递增。同一植被盖度下风蚀量随风速增加而增大,符合幂函数或二次函数关系,但二次函数相关性更高。同一风速下风蚀量随植被盖度的增加呈阶梯式降低,在盖度小于27%时风蚀量平缓下降,盖度27%~43%时风蚀量急剧下降,盖度43%以上时风蚀量下降重新趋于平缓。相对截留率随风速增大而减小,随植被盖度增加而增大,沙丘草本植被盖度43%以上时具有较好的防风固沙效果,此时平均截留率达88.02%。  相似文献   

Influence of the regional climate variations on lake changes of Zabuye,Dangqiong Co and Bankog Co salt lakes in Tibet     

Wang  Yunsheng  Zheng  Mianping  Yan  Lijuan  Bu  Lingzhong  Qi  Wen 《地理学报(英文版)》2019,29(11):1895-1907

Journal of Geographical Sciences - The lake hydrological and meteorological data of the Tibetan Plateau are not rich. This research reports the observed climatic data and measured water levels of...  相似文献   

Stem radial growth indicate the options of species,topography and stand management for artificial forests in the western Loess Plateau,China     

ShengChun Xiao  XiaoMei Peng  QuanYan Tian  Gong Zhu 《寒旱区科学》2019,11(3):226-238

An understanding of the differences in artificial forest between tree species,slope aspects,and management options in arid environments is fundamentally important for efficient management of these artificial systems;however,few studies have quantified the spatial and temporal differences in stem radial growth of trees in the arid western Loess Plateau of China.Using dendrochronology,we assessed the growth of three woody species(the native shrub Reaumuria soongorica,the exotic shrub Tamarix ramosissima and tree Platycladus orientalis)by measuring the annual stem radial increment.We also describe the long-term growth trends and responses to climatic factors on slopes with different aspects during periods with and without irrigation.We found that precipitation during the main growing season was significantly positively correlated with ring growth for all three species and both slope aspects.In addition,supplemental water(e.g.,irrigation,rainwater harvesting)greatly relieved drought stress and promoted radial growth.Our results suggest that as the main afforestation species in the Loess Plateau used for soil and water conservation,P.orientalis is more suitable than T.ramosissima under rain-fed conditions.However,a landscape that combined a tree(P.orientalis)with a shrub(R.soongorica)and grassland appears likely to represent the best means of ecological restoration in the arid western Loess Plateau.  相似文献   

珠江口伶仃洋地貌特征演变与纳潮能力变化研究     

宫清华  周晴  李平日  刘旭拢 《海洋学报》2019,41(1):98-107

在自然和人为的双重作用下,珠江口伶仃洋地貌特征发生了巨大变化,改变了水动力环境,致使纳潮能力也发生深刻变化。本文以珠江口伶仃洋地貌变化和纳潮能力变化为研究对象,采用近百年来的古地图资料、人类活动和水文特征等资料,通过第四纪地质学、地图学、遥感学、历史地理学等方法,反演内伶仃洋形态变化过程,探讨1906年以来珠江口伶仃洋的地貌变化过程。采用岸线分维数、形状指数、纳潮量、潮差消减能力,定量反映地貌变化对纳潮能力的影响。结果表明,1906-2014年,地形演变造成伶仃洋纳潮量减少了14.50%;1971-2014年,伶仃洋纳潮量减少了11.27%。海岸线的变化引起纳潮能力逐渐变弱,潮差沿程变化率减小了0.23,尤其是自1971年以来,因堤围等建设,河口岸线逐渐平直,纳潮能力逐渐减弱。  相似文献