水分再分布过程中指流特性及影响因素的实验研究   总被引：1，自引：0，他引：1  

李贺丽    李怀恩  胥彦玲 《地理科学进展》2010,29(2):173-178

水分在土壤中的运移过程可分为土体表面存在水分供给的入渗过程和水分供给结束后水分在土体中的再分布过程两个阶段。指流作为一种优先流,区别于大孔隙流和漏斗流。国外已有研究指出,指流可以在充分供水结束后的土壤水分再分布过程中出现。然而,目前国内对指流的研究极少,对其认识和理解也相当缺乏。由此,本文采用石英砂介质对其进行了实验验证,分析了水分再分布过程中指流的特性;同时探讨了前期供水量、实验土箱尺寸、溶液浓度等因素对其发育的影响。研究结果表明,水分再分布过程中,均匀砂质土体中易于出现指流;前期供水量的多少对随后水分再分布过程中指流发育的最终形态影响不大,但能够对指流发育进程产生明显的影响;实验土箱较小时,可使原来指流发生比较明显的土体系统呈现出稳定形态;增大单一溶液的浓度对指流发育有着明显的促进作用,但其指流现象较采用自来水的处理为弱。  相似文献   

Two new species of Sellaphora (Bacillariophyta) from a deep oligotrophic plateau lake, Lake Fuxian in subtropical China     

李艳玲  龚志军 《中国海洋湖沼学报》2010,28(6):1160-1165

We describe two new species of Sellaphora from Lake Fuxian, Yunnan Plateau, China. Based on both light and scanning electron microscopy, these species are described as S. yunnanensis sp. nov. and S. sinensis sp. nov. The primary features of S. yunnanensis are: elliptical to linear-elliptical valves with broadly rounded ends, straight filiform raphe, almost straight central endings and small, slightly expanding central pores, small central area, symmetrical or slightly asymmetrical central nodule. The primary features of S. sinensis are: elliptical valves, obtusely rounded ends, similar raphe and axial area, transapically less expanded central area, larger, elliptical central nodule. We compare these species to those of a similar shape and morphology.  相似文献   

用同相叠加方法识别定点形变数据中的降雨影响     

杨学慧  常玉巧  李燕玲  应骁睿  杨海鹏  崔庆谷 《大地测量与地球动力学》2016,36(10):936-940

分别以昆明台、云龙台为例,用数据同相位叠加的方法分别对形变数据中的典型图像及其对应时段的降雨数据进行叠加,以判断典型图像是否与降雨有关。结果表明,昆明台形变观测中多次出现的同步转折为降雨影响;而云龙台的转折现象则与降雨无关,其来源及属性需要进一步研究。  相似文献   

轻小型航空遥感系统空对地检校试验分析     

韩晓冬  杨娜  刘力荣  关艳玲 《测绘通报》2013,(1):33-36

对高精度轻小型航空遥感空对地检校试验进行分析.在已有检校场基站及控制点、检查点布设方案的基础上,结合项目实际需要,提出满足项目需求的检校场布设方案.通过检校场空三及检校参数计算结果,评价检校场布设的合理性,并以国外成熟的POS AV610直接地理定位精度为参照,评价国产POS直接地理定位精度及可行性.  相似文献   

面向交通事件管理的GIS-T数据模型   总被引：1，自引：0，他引：1  

郭鹏  孙艳玲  马寿峰  崔铁军  陈晓玲 《测绘通报》2011,(6):25-28

从交通事件管理角度出发,归纳总结交通事件管理对GIS-T数据模型7个方面的功能需求,在此基础上提出面向交通事件管理的GIS-T数据模型,并利用UML对模型进行构建、分析和描述。  相似文献   

The Relationship Between June Precipitation over Mid-Lower Reaches of the Yangtze River Basin and Spring Soil Moisture over the East Asian Monsoon Region   总被引：1，自引：0，他引：1       下载免费PDF全文

ZHAN Yanling  LIN Zhaohui 《Acta Meteorologica Sinica》2011,25(3):355-363

Using the US Climate Prediction Center(CPC)soil moisture dataset and the observed precipitation over China together with the NCEP/NCAR reanalysis wind and air temperature,the relationship between June precipitation over mid-lower reaches of the Yangtze River basin(MLR-YRB)and spring soil moisture over the East Asian monsoon region was explored,with the signal of the ENSO effect on precipitation removed.A significant positive correlation was found between the mean June precipitation and the preceding soilmoisture over the MRL-YRB.The possible response mechanism for this relationship was also investigated.It is found that when the soil over the MRL-YRB is wetter(drier) than normal in April and May,theair temperature in the lower troposphere over this region in May is lower(higher) than normal,and this temperature effect leads to a decrease(increase) in the temperature contrast between the land and the sea.Generally,a decrease(increase) in the land-sea temperature contrast leads to weaker(stronger) East Asian summer monsoon in June.Southerly(northerly)wind anomalies at 850 hPa then show up in the south of the Yangtze River basin while northerly(southerly)wind anomalies dominate in the north.These anomalies lead to the convergence(divergence) of wind and water vapor and hence gives rise to more(less) precipitation in June over the MLR-YRB.  相似文献   

竖向质量分布对框架结构动力特性影响的研究   总被引：2，自引：0，他引：2  

祝文畏  杨学林  岳燕玲 《地震工程与工程振动》2011,31(5):97-103

在框架结构动力分析中,往往是把填充墙质量集中在楼层处进行求解.文中考虑填充墙实际分布对结构自振特性的影响,通过传递矩阵法求解结构自振频率和振型,并进一步分析了高阶频率的分布规律.结果表明,与采用集中质量模型的振型叠加法相比,填充墙的竖向质量分布会对框架结构高阶频率产生很大影响;框架结构的高阶模态具有局部性和密集分组的特...  相似文献   

东亚地区北方气旋和南方气旋活动频数的时空特征     

王艳玲  王黎娟 《辽宁气象》2011,(6):43-48

利用1953-2007年NCEP／NCAR再分析逐日海平面气压场资料,统计分析东亚地区北方气旋和南方气旋的时间和地域分布特征。结果表明：南、北气旋活动频数存在明显的年际和年代际变化,伴随着一次全球性的年代际气候跃变,20世纪80年代初期北方气旋活动频数出现了显著的突变。从月际分布可知,5月北方气旋频数最多,8月南方气旋频数最多;春季北方气旋活动频繁,存在着明显的两个高值中心,分另Ij位于蒙古国中部和中国东北地区北部;夏季南方气旋活动频繁,主要集中在中国东部沿海及日本南部海面。南北气旋活动频数的季节变化与大气环流的变化密切相关。相关统计结果可增加对东亚温带气旋活动规律的认识和了解,并为预测和预报提供参考。  相似文献   

The impact of sulfate reduction on the distribution of methylmercury in reservoirs in the city of Guiyang     

HE Tianrong  LI Ting  Yang Ruidong  LUO Guangjun  LANG Xiaofang  An Yanling  YAN Haiyu 《中国地球化学学报》2013,32(1):104-109

In this paper, the relationship between sulfate reduction potential and mercury methylation potential was studied in the Aha, Baihua and Hongfeng reservoirs from Guiyang City. The methylmercury (MeHg) concentrations of lake water in the Aha Reservoir were greatly elevated as compared to those of the Hongfeng and Baihua reservoirs, which was correlated with its distinctly high SRB abundance, SO42-, and S2- concentrations. Among the three reservoirs, however, the highest MeHg was observed in in the top several centimenters of pore water profile in the Hongfeng Reservoir where the lowest S2- in pore water occurred. The distributions of MeHg in lake water and pore water showed the highest methylation potential occurred at water-sediment surface for the Aha Reservoir and the in the top several centimenters of sediments for the Hongfeng Reservoir. It is guessed that the highest mercury methylation only occurs at the sites with certain sulfide concentrations.  相似文献   

Metamorphic and Basic Rocks in Middle Hainan Island: Preliminary Geochemical and Petrological Studies and Tectonic Significance     

Zhou Zuyi  Ding Shijiang  Liao Zongting  Xu Changhai  Lao Qiuyuan 《Gondwana Research》1999,2(4):643-646

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