华北地区香河站对流层NO_2的MAX-DOAS光谱仪观测及变化特征分析   总被引：2，自引：0，他引：2       下载免费PDF全文

王婷  王普才  余环  孙丽 《气候与环境研究》2014,19(1):51-60

利用中国科学院大气物理研究所香河大气探测综合试验站2010年3月至2012年2月(2年)的多轴差分吸收光谱仪(MAX-DOAS)观测数据和32 m高塔常规气象资料,反演了华北地区香河站对流层NO2柱浓度,分析了该区域NO2柱浓度的季节变化特征。研究表明:可见光455~485 nm、紫外330~370 nm都可以作为MAX-DOAS工作波段很好地反演NO2;香河地区NO2柱浓度夏季最低,几乎保持在2×1016 cm–2以下,春、秋季次之,在3×1016 cm–2上下小范围浮动,冬季最高,可达4.5×1016 cm–2;月平均最低值出现在7月,最高值出现在11月。NO2柱浓度与风速、风向密切相关:来自东边唐山方向的风,风速越大时NO2浓度越高,因为唐山是NO2的高值区之一;其它方向风速越大,浓度越低。春、夏两季NO2柱浓度日变化趋势比较平缓,秋、冬两季日变化明显,秋季正午偏高,冬季早晚偏高。  相似文献   

西风角动量输送的气候特征及其与急流关系研究     

杨玮  王盘兴  何金海  李丽平  成丽萍 《大气科学》2014,38(2):363-372

利用1958～1997年NCEP/NCAR一日四次的风场再分析资料,系统地分析了季节平均西风角动量（即u角动量）经向、垂直输送通量及其三个分量（平均经圈环流、定常波、瞬变涡输送通量）的气候特征,特别是讨论了12～2月、6～8月它们与东、西风带、副热带西风急流、极夜急流之间的联系。结果表明:（1）包含纬度因子的角动量通量与动量通量在高纬地区存在显著差别,高纬对流层上部的强动量输送中心在角动量通量中不明显。而u角动量强经向输送主要在中低纬对流层顶附近和冬半球高纬平流层顶附近,副热带西风急流和极夜西风急流均位于u角动量强向极输送中心及其高纬一侧的辐合区中。（2）发现三个输送分量对急流维持的作用随纬度、季节不同。北半球冬季（夏季）的副热带西风急流主要由平均经圈环流（强度相当的定常波和瞬变涡）强经向输送及辐合维持;南半球西风急流全年均由平均经圈环流和瞬变涡旋输送及辐合维持;冬半球中平流层极夜急流主要由定常波、瞬变涡旋输送及其辐合共同维持。（3）热带东风区是牵连角动量（即Ω角动量）的高值区,它主要由平均经圈环流向对流层上部输送;冬半球副热带及中纬西风区存在u角动量垂直输送的切变区,它主要由平均经圈环流和瞬变涡旋完成;热带对流层顶附近有u角动量的定常波弱向下输送。  相似文献   

中国近海蟹守螺科(Cerithiidae)两新纪录种及常见种名修订   总被引：1，自引：0，他引：1  

孙启梦  张树乾  张素萍 《海洋与湖沼》2014,45(4):902-906

在系统整理研究中国科学院海洋研究所历年来在中国近海采集的蟹守螺科标本时,鉴定出属于蟹守螺属(Cerithium)的中国两新记录种,分别是:阶梯蟹守螺Cerithium novaehollandiae Adams in Swoerby,1855和锉形蟹守螺Cerithium scobiniforme Houbrick,1992。两新记录种分布于中国海南省沿海,栖息于潮间带至浅海的岩礁、砂或石砾质海底。文中对两新记录种的外部形态、软体部、厣特征和习性及地理分布等方面进行了论述,并与相似种进行了比较。且对中国近海蟹守螺科一些常见种名进行了修订。  相似文献   

Sediment records of environmental changes in the south end of the Zhejiang-Fujian coastal mud area during the past 100 years     

王琳淼  李广雪  高飞  刘玲  刘勇 《中国海洋湖沼学报》2014,32(4):899-908

Previous studies carried out in the East China Sea （ECS） mud area focused on long-term environmental changes in sedimentary records during the Holoeene, especially during the mid-Holocene high-stand water levels period. These results indicate that sensitive grain size groups can be used as a sedimentary proxy to reconstruct the evolution of the East Asian Winter Monsoon （EAWM）. The studies have been carried out mainly in the northern and middle portions of the Zhejiang-Fujian coastal mud, however, similar research in the southern portion and the comparison between sedimentary proxy and modern measured data of EAWM are lacking. In this paper, we focused on a sedimentary record of the past 100 years with an enhanced resolution of 1.8 years. Investigations of the southern end of the Zhejiang-Fujian coastal mud area were conducted on the basis of 21~Pb chronology, grain-size analysis and chemical element analysis. The correspondence between the mean grain size （Mz） of sediment sensitive grain size and the measured EAWM was confirmed for the first time. We found that during the recent 100 years, the variation of the mean grain size of the sensitive population in the southern portion of the Zhejiang-Fujian mud was mainly controlled by the EAWM intensity changes; and not directly related to changes in the sediment discharge from Datong station of the Changjiang River （DTSD）. Finally, recent changes in the content of heavy metals in study area reflect the impact of human activities on the environment.  相似文献   

基于遗传算法的瞬变电磁法线圈阵列优化设计     

杨龙成陆继庆  刘冀成张　帅 《成都信息工程学院学报》2014,(1):28-32

为解决瞬变电磁检测技术遇到地底干扰物时在探测精度方面的不足,从载流直导线出发,利用磁场矢量叠加原理,计算单个正三角形空间磁场分布,设计了一种正三角形发射线圈阵列。为得到更好的磁聚焦特性,利用遗传算法对线圈阵列的具体参数进行优化。仿真结果表明:87.5%及以上的磁场能量集中在半径0.113m的特定区域内。说明该线圈阵列在较小目标区域实现了聚焦,具有良好的聚焦性,可以应用在瞬变电磁检测技术发射回线中。  相似文献   

Short- and long-term response of phytoplankton to ENSO in Prydz Bay,Antarctica: Evidences from field measurements,remote sensing data and stratigraphic biomarker records     

Jun Zhao  Hans-Ulrich Peter  Haisheng Zhang  Zhengbing Han  Chuanyu Hu  Peisong Yu  Bing Lu  Thomas S. Bianchi 《中国海洋大学学报(英文版)》2014,13(3):437-444

The study provides one of the first lines of evidence showing linkages between Antarctic phytoplankton abundance and composition in response to ENSO, based on historical reconstruction of sediment biomarkers. In addition to sediment biomarkers, field measured and remote sensing data of phytoplankton abundance were also recorded from Prydz Bay, Eastern Antarctica. Com-munity structure of field measured phytoplankton showed significant El Ni？o/La Ni？a-related succession during 1990 to 2002. In general, the number of algae species decreased during El Ni？o and La Ni？a years compared to normal years. Austral summer monthly variation of remotely sensed chlorophyll-a （Chl-a）, particulate organic carbon （POC）, and sea surface temperature （SST） indicated that ENSO impacted the timing of phytoplankton blooms during 2007 to 2011. Phytoplankton blooms （indicated by Chl-a and POC） preceded the increases in SST during El Ni？o years, and lagged behind the SST increases during La Ni？a years. Stratigraphic record of marine sedimentary lipid （brassicasterol, dinosterol and alkenones） biomarkers inferred that the proportions of different algae （diatoms, dinoflagellates and haptophytes） changed significantly between El Ni？o and La Ni？a events. The relative proportion of diatoms increased, with that of dinoflagellates being decreased during El Ni？o years, while it was reversed during La Ni？a years.  相似文献   

基于定向片模型的SPOT-5遥感影像自检校光束法平差     

贾博  姜挺  张锐  江刚武 《测绘科学》2014,39(9)

本文通过建立内方位自检校模型,利用定向片模型对外方位元素进行内插建模,建立了基于定向片模型的自检校光束法平差,研究不同控制点数量和不同定向片间隔对定位精度的影响,并利用河南嵩山地区SPOT-5遥感影像数据对模型进行了实验验证和分析,结果表明,平面精度可以达到10.06m,高程精度可以达到8.84m.  相似文献   

On the influence of vertical loads on the lateral response of pile foundation     

《Computers and Geotechnics》2014

The influence of vertical loads on the lateral response of group piles installed in sandy soil and connected together by a concrete cap is studied through finite elements analyses. The analyses focus on the five piles in the middle row of 3 × 5 pile groups. The vertical load is applied by enforcing a vertical displacement equivalent to 2% of the pile diameter through the pile cap prior to the application of the lateral loads. The results have shown that the lateral resistance of the leading pile (pile 1) does not appear to vary considerably with the vertical load. However, the vertical load leads to 23%, 36%, 64%, and 82% increase in the lateral resistance of piles 2–5, respectively. The increase in the lateral pressures in the sand deposit is the major driving factor to contribute the change in the lateral resistance of piles, depending on the position of the pile in the group. The distribution of lateral loads among piles in the group tends to be more uniform when vertical loads were considered leading to a more economical pile foundation design.  相似文献   

断层输导作用与油气充注作用关系分析   总被引：2，自引：0，他引：2       下载免费PDF全文

刘震  张旺  曹尚  刘明洁  张威  董冬 《地质科学》2014,49(4):1302-1313

断层是控制油气藏形成的重要因素之一;断层的开启及闭合影响到油气运移与聚集的效率。但油气在断层中的运移与在砂层中的充注存在差异性这一问题长期被忽视。一般认为;只要发育断层;其断开的渗透层就会被油气充注;极少关注地层水和石油的压缩特性对充注的影响。本文提出;地下单断层活动时;深部油气在超压作用下以涌流方式难以快速充注进入中浅层被切割的砂体;因此;单砂体至少要存在一条断层作为泄水出口;石油才能通过其余断层充注进入砂体;即单砂体要发育两条及两条以上断层;石油才能注入砂体。在断层静止期;油气通过渗流方式沿特定深度范围断面垂向运移;对油气垂向运移距离影响较小。本文运用4个大型盆地的典型油气藏与断层分布关系讨论了本文观点。该观点对油气成藏规律研究及成藏目标评价有较重要参考意义。  相似文献   

Effects of Crustal Structure for Estimation of Vertical Load Deformation on the Solid Earth Using GRACE in China Mainland     

Jia Lulu  Xiang Longwei  Wang Hansheng 《地球科学进展》2014,29(7):828-834

When the inversion of vertical load deformation on Earth’s surface using GRACE (Gravity Recovery and Climate Experiment) data, the load Love numbers based on PREM (Preliminary Reference Earth Model) are commonly used. But the crustal structure under China mainland especially under Tibet Plateau is quite different from that given by PREM Earth model. New load Love numbers were calculated based on a modified Earth model which accounted for regional crustal structure in China mainland. And the effect of regional crustal structure in China mainland for estimation of vertical load deformation on Earth’s surface using GRACE RL05 data was investigated in this paper. It is found that the effect of crustal difference is very prominent. The relative difference of load Love numbers for vertical deformation can reach about 11% at degree 90. The extreme value of difference in vertical load deformation below 90 degree of spherical harmonic coefficients located at the southeastern Tibet Plateau and the maximum relative difference reaches 10%. The relative difference of the root mean square is about 4%. It is suggesting that an Earth model with a more realistic crustal structue instead of PREM should be used for the estimation of vertical load deformation in China mainland espacially in Tibet Plateau.  相似文献