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1.
北疆牧区MODIS积雪产品MOD10A1和MOD10A2的精度分析与评价 总被引：19，自引：9，他引：10
以北疆为研究区,结合气象台站记录的雪情数据,利用地理信息系统方法分析了2004年12月1日至2005年2月28日期间北疆地区90个时相的MODIS每日积雪产品MOD10A1和8日合成产品MOD10A2的积雪分类精度.研究表明:1)当积雪深度≤3 cm时,MOD10A1对积雪的识别率非常低,仅为7.5%;积雪深度为4~6 cm时,积雪识别率达到29.3%;积雪深度为15~20 cm,平均积雪识别率达到45.6%.当积雪深度>20 cm时,平均积雪识别率为32.2%;2)MOD10A1产品的积雪分类精度受天气状况的严重影响.在晴空状况下,该产品的最大积雪识别率达到58.2%;但是在多云或阴天时,平均积雪识别率仅为17.8%;3)下垫面对MOD10A1的分类结果也会造成影响,在荒漠区MOD10A1的积雪识别率为39.8%,在草原和稀树草原区的积雪识别率为37.2%,农业用地的积雪识别率最低,为29.1%;4)MOD10A2产品可较好的消除云层对地表积雪分类精度的影响,平均积雪识别率达87.5%,可较好的反映地表积雪的分布状况. 相似文献
2.
1987年8月王宁等报道具有八次对称轴准晶的高分辨图象,呈现出正八边形相嵌的图案。本文认为从配位多面体理论上对八次对称存在的可能性加以研究是有必要的,为此提出了具有十次配位的等腰三角十六面体和一系列带帽反棱柱,精确地求出了这些十六面体的顶点间的夹角、棱长和晶面法线与四次轴间的夹角等几何参数,作为应用对于Cr—V—Ni—Si八次对称准晶,设Ni原子（简称原子A）位于多面体中心,而V,Cr,Si原子（简称原子B）位于顶点上,原子A和B之半径分别为1.24（?）和1.32（?）,间隙0≤（?）（?）≤0.6（?）.则:（1）若原子A和B按等腰三角十六面体配位且A,B的键长为（2.56+δ）（?）,则原子B间的键长为1.08（2.56+δ）（?）或1.29（2.56+δ）（?）;（2）若原子A和B按带帽反棱柱配位且呈“紧密堆积”,则原子A和B之间的键长为（2.56+δ）（?）或（2.56+δ）(0.511+（0.261+[0.08/（2.56+δ）]n）1/2（?） 相似文献
3.
贵州地震时空分布规律探析 总被引：1，自引：1，他引：0
如果以垭都—紫云—罗甸断裂带北东侧为界将贵州省分为A、B两个区域,则：①地震在A区分布较为密集,而在B区分布较为稀散。单位国土面积上释放的地震能量,前者比后者要大一个数量级,反映两者在力学性质上存在较大差异。②A区地震释放能量在深度约5.5km处突然出现一个高达2个数量级的跃升,在深度约7 km处回落到接近跃升前的位置,而后又逐渐下降,反映该区域5.5～7 km深度地层的力学强度较低。③贵州地震释放能量总体似乎呈周期性变化,变化周期在11～15年间变动。A、B两区域地震释放能量的高峰年有此消彼长的现象,即A区出现地震活动高峰时,B区相对比较平静;而B区出现地震活动高峰时,A区相对比较平静。 相似文献
4.
The Neoproterozoic Katangan R.A.T. (“Roches Argilo-Talqueuses”) Subgroup is a sedimentary sequence composed of red massive to irregularly bedded terrigenous-dolomitic rocks occurring at the base of the Katangan succession in Congo. Red R.A.T. is rarely exposed in a continuous section because it was affected by a major layer-parallel décollement during the Lufilian thrusting. However, in a number of thrust sheets, Red R.A.T. is in conformable sedimentary contact with Grey R.A.T which forms the base of the Mines Subgroup. Apart from the colour difference reflecting distinct depositional redox conditions, lithological, petrographical and geochemical features of Red and Grey R.A.T. are similar. A continuous sedimentary transition between these two lithological units is shown by the occurrence of variegated to yellowish R.A.T. The D. Strat. “Dolomies Stratifiées” formation of the Mines Subgroup conformably overlies the Grey R.A.T. In addition, a transitional gradation between Grey R.A.T. and D. Strat. occurs in most Cu–Co mines in Katanga and is marked by interbedding of Grey R.A.T.-type and D. Strat.-type layers or by a progressive petrographic and lithologic transition from R.A.T. to D. Strat. Thus, there is an unquestionable sedimentary transition between Grey R.A.T. and D. Strat. and between Grey R.A.T. and Red R.A.T.The R.A.T. Subgroup stratigraphically underlies the Mines Subgroup and therefore R.A.T. cannot be comprised of syn-orogenic sediments deposited upon the Kundelungu (formerly “Upper Kundelungu”) Group as suggested by Wendorff (2000). As a consequence, the Grey R.A.T. Cu–Co mineralisation definitely is part of the Mines Subgroup Lower Orebody, and does not represent a distinct generation of stratiform Cu–Co sulphide mineralisation younger than the Roan orebodies. 相似文献
5.
Rajeev?SARASWAT Manumalenki?MANASA Thejasino?SUOKHRIE Mohammad?Syed?SAALIM Rajiv?NIGAM 《《地质学报》英文版》2017,91(6):2268-2282
A total of 97 surface sediment samples were collected from the continental shelf and slope of the western Bay of Bengal to assess the potential application of Asterorotalia trispinosa as a paleomonsoon proxy. The relative abundance of living as well as total (living and dead) A. trispinosa ranges from being absent to a maximum of ~31%. The highest abundance of A. trispinosa is close to the outfall region of the Ganga-Brahmaputra Rivers and decreases away from the river mouths. Contrary to that, A. trispinosa is rare in front of both the Cauvery and Pennar river outfall regions, in the central part of the western Bay of Bengal. The living A. trispinosa abundance is the lowest in between two major river systems, viz. Ganga-Brahmaputra-Mahanadi and Krishna-Godavari. The relative abundance of both the total and living A. trispinosa is strongly positively correlated with ambient seawater temperature, and negatively correlated with %Corg and salinity. Based on the spatial distribution, we conclude that A. trispinosa is stenohaline in nature, rather than euryhaline, and further that the increased relative abundance of A. trispinosa indicates warmer and only marginally hyposaline environment. Even though the ecological preference of A. trispinosa suggests it as a potential paleomonsoon proxy, the restricted distribution implies limited application. 相似文献
6.
四川盆地深层海相碳酸盐岩气藏成藏模式 总被引：3，自引：2，他引：1
四川盆地深层碳酸盐岩气藏主要指中三叠统雷口坡组及更老层位海相碳酸盐岩为储层形成的气藏,一般(曾)埋深在4500m之下,按类型可分为原生气藏(生气中心、储气中心和保气中心位于同一层位内)和次生气藏(生气中心、储气中心与保气中心位于不同层位)2类。原生气藏储层内含有大量沥青, 天然气主要为原油裂解气。次生气藏储层内不含沥青, 但天然气仍然主要为原油裂解气。原生气藏的成藏模式有三中心叠合模式、储气中心解体模式、三中心短距离移位模式和缺乏保气中心模式。次生气藏的成藏模式主要以天然气跨层运移为主要特征, 其气源来自于先存的天然气藏。三中心叠合模式的原油裂解气成藏效率最高,储气中心解体模式的原油裂解气成藏效率中等,三中心短距离移位模式和次生气藏形成模式的原油裂解气成藏效率较低,保气中心缺乏模式的原油裂解气成藏效率为零。因此,在勘探策略上应重视三中心叠合和储气中心解体模式形成的原生气藏的勘探,同时应关注由震旦系灯影组古气藏(储气中心)破坏而形成的下古生界次生气藏。 相似文献
7.
A highly simplified zonally symmetric system of equations is used to understand the basic mechanism of the northward movement of the 30–50 day oscillation in the Indian monsoon region. Zonally symmetric perturbations are used on the July mean basic flow in the Indian region. A two-level model is employed. A simple parametrization of cumulus heating is included. An expression is derived for the northward phase speed. A right order of magnitude for the phase speed is obtained. The northward movement appears to be controlled by the basic zonal wind profile and cumulus heating. 相似文献
8.
A least-squares analysis of measurements of the Earth-rotation parameters is used to interpolate these data in order to redict the polar motion using a basic mathematical model that includes two frequencies: the Chandler and annual frequencies. A model taking into account the oscillations induced by the influence of the Moon is considered. The manifestation of high-frequency lunar oscillations in the beat period is demonstrated, together with the feasibility of interpolating these oscillations over short time intervals. A comparative analysis of models taking into account the monthly and bi-weekly frequencies is presented. A reasonable model explaining anomalous phenomena in the six-year beating is proposed. 相似文献
9.
Combining Knowledge from Diverse Sources: An Alternative to Traditional Data Independence Hypotheses 总被引：19，自引：0，他引：19
A. G. Journel 《Mathematical Geology》2002,34(5):573-596
Consider the assessment of any unknown event A through its conditional probability P(A | B,C) given two data events B, C of different sources. Each event could involve many locations jointly, but the two data events are assumed such that the probabilities P(A | B) and P(A | C) can be evaluated. The challenge is to recombine these two partially conditioned probabilities into a model for P(A | B,C) without having to assume independence of the two data events B and C. The probability P(A | B,C) is then used for estimation or simulation of the event A. In presence of actual data dependence, the combination algorithm provided by the traditional conditional independence hypothesis is shown to be nonrobust leading to various inconsistencies. An alternative based on a permanence of updating ratios is proposed, which guarantees all limit conditions even in presence of complex data interdependence. The resulting recombination formula is extended to any number n of data events and a paradigm is offered to introduce formal data interdependence. 相似文献
10.
鄂尔多斯盆地中东部奥陶系马家沟组马五6亚段硬石膏产状类型多样,基于系统的宏观与微观岩石学分析,识别并区分出星散状(A1型)、纹层状(A2型)、致密块状(A3型)、结核状或团块状(A4型)、鸡雏状或角砾状(A5型)等硬石膏产状类型。单井高频旋回和微相分析表明,马五6亚段发育与潮坪、潟湖、鲕粒滩、砂屑滩、微生物丘等有关的5种高频向上变浅序列,硬石膏的产状类型、产出位置和分布形式等与向上变浅序列有很好的耦合关系。A1型和A2型硬石膏发育于高频向上变浅序列的下部和中部,主要与膏云质或云膏质潟湖相关,属于潟湖相原生化学沉积成因。A3型硬石膏分布于高频向上变浅序列的上部,受膏质潟湖控制,也属于原生化学沉积成因。经典的结核状硬石膏(A4-1)呈随机分布形式产于潮坪沉积序列,为成岩期交代作用或者膏化作用成因,与传统萨布哈交代成因的膏质结核相似。A4-2型硬石膏主要出现在颗粒岩和微生物岩中,主要由富含CaSO4的下渗卤水在溶蚀孔洞中沉淀形成;A5型硬石膏发育于向上变浅序列的上部和顶部,与高频暴露有关,为准同生期以溶蚀—充填为主的岩溶改造成因。发育完整的单个高频旋回,大致经历了高频快速海侵早期、高频快速海侵晚期至缓慢海退早期、高频缓慢海退晚期和高频海退末期暴露4个演化阶段,形成了与之耦合的海相碳酸盐岩与硬石膏共生序列。这些认识将对马家沟组沉积古环境的再认识具有重要的参考意义。 相似文献
11.
鄂尔多斯盆地中东部奥陶系马家沟组马五6亚段硬石膏产状类型多样,基于系统的宏观与微观岩石学分析,识别并区分出星散状(A1型)、纹层状(A2型)、致密块状(A3型)、结核状或团块状(A4型)、鸡雏状或角砾状(A5型)等硬石膏产状类型。单井高频旋回和微相分析表明,马五6亚段发育与潮坪、潟湖、鲕粒滩、砂屑滩、微生物丘等有关的5种高频向上变浅序列,硬石膏的产状类型、产出位置和分布形式等与向上变浅序列有很好的耦合关系。A1型和A2型硬石膏发育于高频向上变浅序列的下部和中部,主要与膏云质或云膏质潟湖相关,属于潟湖相原生化学沉积成因。A3型硬石膏分布于高频向上变浅序列的上部,受膏质潟湖控制,也属于原生化学沉积成因。经典的结核状硬石膏(A4-1)呈随机分布形式产于潮坪沉积序列,为成岩期交代作用或者膏化作用成因,与传统萨布哈交代成因的膏质结核相似。A4-2型硬石膏主要出现在颗粒岩和微生物岩中,主要由富含CaSO4的下渗卤水在溶蚀孔洞中沉淀形成;A5型硬石膏发育于向上变浅序列的上部和顶部,与高频暴露有关,为准同生期以溶蚀—充填为主的岩溶改造成因。发育完整的单个高频旋回,大致经历了高频快速海侵早期、高频快速海侵晚期至缓慢海退早期、高频缓慢海退晚期和高频海退末期暴露4个演化阶段,形成了与之耦合的海相碳酸盐岩与硬石膏共生序列。这些认识将对马家沟组沉积古环境的再认识具有重要的参考意义。 相似文献
12.
地质样品扫描质子探针元素分布图的本底值剔除研究 总被引：1，自引：0，他引：1
建立了一个简便、可靠的扫描质子探针元素分布图本底值剔除方法，编制了逐点本底计数值剔除计算程序。结合实际地质样品的扫描质子探针元素分布成图，对方法的有效性做了对比实验。结果表明，与传统的成图方法相比，新方法具有图像清晰、真实的优点。同时讨论了方法的误差和误差的减小途径。 相似文献
13.
提出了用岩石Ａ、Ｂ值来表示岩石可钻性级别的新观点,研究了岩石Ａ、Ｂ值测定方法和原理;用岩石Ａ、Ｂ值来指导钻头配方设计是可行的。 相似文献
14.
Nazire
zgen-Erdem Mehmet Akyaz&#x; Asl&#x; Karabaolu 《Journal of Asian Earth Sciences》2007,29(5-6):911-927
The Ilerdian–Middle Cuisian sedimentary succession of the Seyitgazi region, southern Eskişehir (Central Anatolia, Turkey) is composed of claystones, limestones and clayey limestones. It contains abundant benthic foraminifera, particularly species of Alveolina. From this succession, 28 species of Alveolina d’Orbigny are described and their comparative stratigraphic distribution with the Alveolina species in the Tethyan Eocene is documented. Generally, Ilerdian–Cuisian Alveolina assemblages of the Seyitgazi region have close affinities with coeval Alveolina assemblages described in different studies from the Tethyan Province. The Ilerdian unit of the study area is characterized by Alveolina species such as Glomalveolina lepidula, Glomalveolina minutula, G. karsica, Alveolina vredenburgi, A. ellipsoidalis, A. avellana, A. aff. minervensis, A. dedolia, A. moussoulensis, A. subpyrenaica, A. laxa, A. aragonensis, A. varians, A. ilerdensis, A. trempina, A. citrea, A. pisella and A. decipiens. Likewise, the Early Middle Cuisian unit is represented by G. minutula, A. oblonga, A. schwageri, A. haymanensis, A. canavarii, A. aff. coudurensis, A. ruetimeyeri, A. muscatensis, A. cremae, A. bayburtensis and A. lehneri. 相似文献
15.
SWVR—2000型智能综合工程探测仪,是为适应工程勘察领域近年来发展的新方法新技术的需要而研制的,主要用于岩土工程原位测试,混凝土工程强度评价,桩基无损检测以及常时微动监测等方面。数据采集是该仪器的主要部分之一。文中讨论了如何选择A/D转换器,巧妙地利用微机接口的软硬件设计来提高数据采集的速度,给出了数据采集系统的控制策略,最后给出了仪器与系统机联机进行数据通讯的简便方法。 相似文献
16.
基于颗粒组构特性的散体材料本构模型研究 总被引：1，自引：0，他引：1
通过散体介质材料单元颗粒排列组构表达的细观结构力学关系,建立了用颗粒密集度、颗粒排列组构关系和颗粒间摩擦特性等非连续介质材料特性参数描述的散体介质材料本构模型,从而实现散体介质材料宏观连续介质描述的等效应力表达.通过该模型可采用数值方法进行散体介质材料准静态情况下的力学特性分析.文中最后基于有限元软件ABAQUS,进行了该本构模型的二次开发.数值算例结果验证了所建立散体介质材料本构模型的适用性. 相似文献
17.
Permo-Carboniferous Radiolarians from the Wupata''''erkan Group,Western South Tianshan, Xinjiang, China 总被引：3，自引：0，他引：3
LI Yuejun SUN Longde WU Haoruo ZHANG Guangya WANG Guolin HUANG Zhibin Institute of Geology Geophysics Chinese Academy of Sciences Beijing Tarim Oilfield Company PetroChina Korla Xinjiang 《《地质学报》英文版》2005,(1)
1 IntroductionThe Wupata'erkan Group, also called Wupata'erkanFormation (Wang et al., 1990), in the western SouthTianshan, China (Fig. 1), mainly comprises gray and darkgray fine-grained clastic rocks, interlayered with medium-acidic volcanic rocks (andesite and quartz porphyry),carbonates, cherts and variegated tuffaceousconglomerates. The chert in the formation was firstly foundin our field trip along sections of the Qiqi'erjianakesu Riverand Kekebiele Daban. Deformation of the group is… 相似文献
18.
新疆东准噶尔两类碱性花岗岩及其地质意义 总被引：19，自引：0，他引：19
研究证明,东准噶尔境内广泛发育的碱性花岗岩在空间上与深断裂、蛇绿岩及偏碱性的钾长花岗岩类紧密伴生,并可规律地分为卡拉麦里碱性花岗岩带（简称南带）、乌伦古碱性花岗岩带（简称中带）和布尔根碱性花岗岩带（简称北带）。南、中两带碱性花岗岩形成于海西中晚期,图... 相似文献
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20.
LI Yuejun SUN Longde WU Haoruo ZHANG Guangy WANG Guolin HUANG Zhibin Institute of Geology Geophysics Chinese Academy of Sciences Beijing Tarim Oilfield Company PetroChin Korl Xinjiang 《《地质学报》英文版》2005,79(1)
1 IntroductionThe Wupata'erkan Group, also called Wupata'erkanFormation (Wang et al., 1990), in the western SouthTianshan, China (Fig. 1), mainly comprises gray and darkgray fine-grained clastic rocks, interlayered with medium-acidic volcanic rocks (andesite and quartz porphyry),carbonates, cherts and variegated tuffaceousconglomerates. The chert in the formation was firstly foundin our field trip along sections of the Qiqi'erjianakesu Riverand Kekebiele Daban. Deformation of the group is… 相似文献