基于埋深变化的川南龙马溪组页岩孔隙特征及控制因素分析          下载免费PDF全文

陈洋  唐洪明  廖纪佳  罗超  赵圣贤  郑马嘉  钟权 《中国地质》2022,49(2):472-484

[研究目的]中国浅层-中深层页岩气勘探开发技术已经趋于成熟,深层页岩成为下一步勘探开发的重点,探明不同埋深条件下页岩的孔隙特征及其控制因素利于推动深层页岩的评优选区工作.[研究方法]本文基于核磁共振、场发射扫描电镜和X-射线衍射等实验分析手段,对比性评价了川南地区不同深度的龙马溪组页岩孔隙度、孔隙结构参数特征并进行影响...  相似文献   

海翼水下滑翔机测流应用     

褚福硕  司宗尚  庞重光  俞建成 《海洋科学》2022,46(5):10-16

水下滑翔机其通过集成生物、化学、物理传感器可以测量如温度、盐度、溶解氧等多种海洋基础水文要素,其利用卫星定位系统获得实际出水速度和理论出水模型获得理论出水速度之差可以计算深度平均流,。本文利用海翼水下滑翔机获得温盐场及卫星定位数据评估深度平均流,结果显示利用温盐场获得深度平均地转流与水下滑翔机获得深度平均流相关系数0.95,表明其流场的一致性,同时根据船载观测ADCP误差分析法估算深度平均流误差约为0.036 m/s。借助深度平均流可以估算绝对地转流,包括正压地转流和斜压地转流。在零动力面的假设下,我们选取了海翼号水下滑翔机在南海的一组实验对流量误差进行了评估。该实验为2019年1月3日-2月16日海翼号水下滑翔机自南向北穿越西沙群岛附近一个中尺度涡观测。观测结果表明,该中尺度涡为冷涡流核,在涡心以南,绝对地转流为东向流,最大流速约为0.48 m/s;涡心以北,绝对地转流为西向流,最大流速约为0.47 m/s,稍弱于南侧。受不均匀时空观测计划影响,本文未对流量做出估计。  相似文献   

Imag(in)ing the continental lithosphere   总被引：1，自引：0，他引：1  

Alan Levander  Fenglin Niu  Cin-Ty A. Lee  Xin Cheng 《Tectonophysics》2006,416(1-4):167

This paper is primarily concerned with seismically imaging details in the mantle at an intermediate scale length between the large scales of regional and global tomography and the small scales of reflection profiles and outcrops. This range is roughly 0.1–1 km < a < 10–10² km, where a is the scale. We consider the implications of several models for mantle evolution in a convecting mantle, and possible scales present in the non-convecting tectosphere. Reflection seismic evidence shows that the structures preserved from continental accretion within and at the margins of the Archean cratons are subduction related, and we use subduction as an analog for scales left by past events. In modern orogenic belts we expect to find subduction structures, small scale upper mantle convection structures, and basalt extraction structures. We examine some of the scales that are likely formed by orogenic processes.We also examine the seismic velocity and density contrasts expected between various upper mantle constituents, including fertile upper mantle, depleted upper mantle, normal and eclogitized oceanic crust, and fertile mantle with and without partial melt. This leads directly to predicting the size of seismic signals that can be produced by specular conversion, and scattering from layers and objects with these contrasts.We introduce an imaging scheme that makes use of scattered waves in teleseismic receiver functions to make a depth migrated image of a pseudo-scattering coefficient. Image resolution is theoretically at least an order of magnitude better than traveltime tomography. We apply the imaging scheme to three data sets from 1) the Kaapvaal craton, 2) the Cheyenne Belt, a Paleoproterozoic suture between a protocontinent and an island arc, and 3) the Jemez Lineament, a series of aligned modern volcanic structures at the site of a Proterozoic suture zone. The Kaapvaal image, although not defining a unique base of the tectosphere, shows complicated “layered” events in the region defined as the base of the tectosphere in tomography images. The image of the transition zone discontinuities beneath the Kaapvaal craton is remarkable for clarity. The migrated receiver function image of the upper mantle beneath the Cheyenne belt is complicated, more so than the tomography image, and may indicate limitations in the receiver function imaging system. In contrast the Jemez Lineament image shows large-amplitude negative-polarity layered events beneath the Moho to depths of 120 km, that we interpret as melt-containing sills in the upper mantle. These sills presumably feed the Quaternary–Neogene regional basaltic volcanic field.  相似文献   

浙江省空气质量与大气自净能力的特征分析   总被引：1，自引：0，他引：1  

郁珍艳  李正泉  高大伟  王阔 《气象》2017,43(3):323-332

利用最新的高时空分辨率ERA-Interim探空和地面资料,计算分析了1979—2015年浙江省大气输送和自净能力的时空分布变化特征,结合环保局空气质量监测数据探讨了浙江省空气质量与大气自净能力的关系,结果表明:大气自净能力在春、夏季表现出沿海地区小,内陆地区大的分布;到了秋、冬季,沿海地区大气自净能力增大,内陆地区则减小;研究时段内全省平均大气自净能力有增大趋势。表征低层输送能力的10 m风速在秋、冬季最大,夏季最小,随时间略有减小,这是浙江省空气污染加剧的可能原因之一;10 m风速的分布基本呈从东部沿海地区往西部山区逐渐减小的变化趋势,秋、冬季风速略大,以偏北风为主。浙江省大部分地区冬季大气自净能力最差,盛行的偏北风又容易将北方污染物带下来,因此冬季是浙江省最易发生空气污染的时段。当风速较小,风向转为偏西北风时,污染物从北方输入并且积累,最易出现较严重的污染天气。中度及以上的空气污染主要发生在杭嘉湖、宁波、绍兴、金华这些经济发达的地区,沿海地区的舟山、温州、台州由于大气输送条件好发生站次很少。丽水和衢州山区海拔高,加之本地工业经济发展较弱,空气污染发生的频次较少。  相似文献   

季节性积雪区不同遮挡条件下深霜发育比较   总被引：1，自引：0，他引：1  

洪雯  魏文寿  刘明哲  陆恒  韩茜 《地理科学》2012,(8):979-985

以中国科学院天山积雪雪崩研究站为研究区,在2009～2010年冬季观测期利用体视显微镜(XTZ-E)及拍照设备和雪特性分析仪(Snow Fork),对3种遮挡条件的开阔地(0遮挡)、树缘(50%遮挡)和树下(90%遮挡)的积雪深霜进行连续观测,比较和分析西北季节性积雪区不同遮挡条件下的深霜发育特征。研究表明:1)深霜发育主要受温度制约,其次是温度梯度。由不同遮挡条件引起积雪累积和太阳辐射差异而导致雪深不同,从而形成的温度环境差异,是深霜发育差异的根本原因。2)深霜发育厚度与雪深呈正相关关系,有开阔地(0遮挡)>树缘(50%遮挡)>树下(90%遮挡),融雪期深霜的消减速率为树下>开阔地>树缘。3)深霜冰晶粒径呈先减小(稳定累积期-过渡期)再增大(-融雪期)的变化,积雪稳定累积期后,深霜粒径开阔地>树缘>树下。4)2009～2010年冬季雪深大,因而圆角深霜(DHxr)和圆角刻面冰晶(FCxr)在深霜中发育最多,二者共占70%～80%。开阔地易发育杯型深霜(DHcp),树缘和树下则易发育柱状条纹深霜(DHla)、棱柱状深霜(DHpr)和刻面冰晶(FCso)。深霜中胶结态冰晶约占10%～30%,其比例在开阔地深霜中递减,而在树缘和树下处递增。  相似文献   

Investigation of water signatures at gully-exposed sites on Mars by hyperspectral image analysis     

Chaojun Fan  Dirk Schulze-Makuch 《Planetary and Space Science》2009,57(1):93-104

High-resolution images from the Mars Obiter Camera (MOC) onboard the Mars Global Surveyor (MGS) show a variety of gully features on sloped surfaces of Mars. The mechanism of gully formation is still under debate, although a majority of studies tend to favor a mechanism related to liquid water flow based on geomorphology and fluid mechanics considerations. In this study, we examined four known gully sites using Visible and Infrared Mineralogical Mapping Spectrometer (OMEGA) imagery. In particular, we analyzed the absorption depths of the water-associated absorption bands and concluded that there are stronger water signatures at the gully-exposed sites than in the surrounding areas. This implies that the water signatures, most likely representing water ice, isolated water molecules, and/or hydroxyl molecules incorporated into minerals, are still present in the shallow unconsolidated soils. This study provides additional evidence that water was likely involved in the formation of the gully features and is still locally active on the Martian surface in the present time.  相似文献   

Lidar depolarization measurements for aerosol source and property studies over Chungli (24.58° N, 121.1° E)     

C.W. Chiang  S.K. Das  J.B. Nee 《Atmospheric Research》2008,90(2-4):203-ICNAA07

Aerosol depolarization ratio and aerosol optical depth (AOD) were measured at Chungli (24.58° N, 121.1° E), Taiwan during the period from 2002–2004. The depolarization ratios of background aerosol have values mostly less than 0.06. The maximum AOD in the altitude range of 0.7 to 2km occurs in the summer (June–August) while between 2 and 5km, the spring (March–May) shows the maximum. The former is mainly related to strong convection and humidity; however the latter is due to anthropogenic aerosols transported from East China and Southeast Asia based on calculations of backward trajectories. This seasonal variation of AOD inferred from different transport mechanisms and aerosol compositions which are supported by the height distributions of aerosol extinction and origins.  相似文献   

青海地区常规观测积雪资料对比及积雪变化趋势研究   总被引：1，自引：1，他引：0  

雷俊  方之芳 《高原气象》2008,27(1):58-67

应用青海44个台站1962—2005年逐月积雪深度和积雪日数资料,对比了这两份常规积雪资料在表征青海地区积雪变化特征上的一致性,并对近十几年来的积雪变化新趋势做了分析。结果表明:积雪深度和积雪日数均能比较一致地反映整个青海地区积雪变化趋势:夏、秋季积雪从20世纪60年代至21世纪初为一致的减少趋势;冬、春季积雪在20世纪60年代至90年代初增加,而从20世纪90年代中期至21世纪初积雪呈显著减少趋势。后期的减少趋势远比前期的增加趋势明显。青海地区不同季节积雪深度和积雪日数趋势变化明显的区域基本一致,但中心位置存在一定的差异。冬季在32.5°~35°N,95°~102°E范围内的唐古拉山、巴颜喀拉山和阿尼玛卿山区,春季在青海东南部阿尼玛卿山区附近,均明显地表现出20世纪90年代中期以后积雪的减少和前期积雪的增加。不同季节积雪深度和积雪日数的相关系数分布存在一定差异:冬季两份资料相关相对较小的区域位于青海中南部巴颜喀拉山西区至阿尼玛卿山西区一线;春季相关系数小于冬季,青海东北边缘以及东南边缘地区,相关系数未能通过95%信度检验;夏、秋季积雪较少,相关较小的区域集中在青海东南部地区。而上述区域大多为各个季节积雪较多的地区,应慎重使用该区域的常规积雪资料。综合分析两份积雪资料,确定青海地区冬季多雪年为1964,1975,1993,1995和1998年,少雪年为1963,1965,1969,1997和2003年;春季多雪年是1977,1982,1987,1989和1990年,少雪年是1969,1979,1985,1999和2001年。  相似文献   

对云滴凝结增长方程的质疑     

周少祥 《沙漠与绿洲气象(新疆气象)》2008,2(4):55-59

基于多元体系化学势和相平衡原理,分析认为“水蒸气凝结释放的潜热既升高了云滴表面温度,又向外传导热量”的观点违反了热力学第二定律,指出这样热传导过程是不可能进行的,分析认为大气中水蒸气凝结只能以辐射形式释放潜热。  相似文献   

1999-2003年我国气溶胶光学厚度的变化特征   总被引：9，自引：2，他引：7  

杨琨  孙照渤  倪东鸿 《南京气象学院学报》2008,31(1):92-96

利用我国70站1999-2003年1月、4月、7月、10月月平均水汽压和能见度资料,反演得到各站大气气溶胶光学厚度（AOD,aerosol optical depth）,分析了气溶胶光学厚度的变化特征。结果表明：中国多年平均大气气溶胶光学厚度的分布是以四川盆地为中心向四周减少,长江中下游和广东沿海为两个次大值中心,而东北和西北大部分地区以及云南等地AOD较小;各季节AOD的空间分布都有所不同;近5aAOD有弱增加趋势;月平均气溶胶光学厚度与能见度有较好的负相关关系。  相似文献