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921.
松辽盆地东南隆起区深层断陷的构造特征及其对油气勘探的意义 总被引:2,自引:0,他引:2
在8km×8km测网地震资料对比解释的基础上,研究了松辽盆地东南隆起区深层断陷的发育概况,认为断陷的主要发育时期为沙河子期,发育8个不等的断陷。根据地震解释结果等相关资料,分析了断陷期火石岭组、沙河子组和营城组的分布差异。结合区域地质背景,认为松辽盆地东南隆起区深层断陷期主要经历了初始裂陷期(火石岭期)、强烈断陷期(沙河子期)和断坳转换期(营城期)3个演化阶段。对深层断陷地层遭受的改造作用进行了分析。 相似文献
922.
By using the improved regional climate model (BCC_RegCM1.0), a series of modeling experiments are undertaken to investigate the impacts of historical land-use changes (LUCs) on the regional climate in China. Simulations are conducted for 2 years using estimated land-use for 1700, 1800, 1900, 1950, and 1990. The conversion of land cover in these periods was extensive over China, where large areas were altered from forests to either grass or crops, or from grasslands to crops. Results show that, since 1700, historical LUCs have significant effects on regional climate change, with rainfall increasing in the middle and lower reaches of the Yangtze River Basin, Northwest China, and Northeast China, but decreasing by different degrees in other regions. The air temperature shows significant warming over large areas in recent hundred years, especially from 1950 to 1990, which is consistent with the warming caused by increasing greenhouse gases. On the other hand, historical LUCs have obvious effects on mean circulation, with the East Asian winter and summer monsoonal flows becoming more intensive, which is mainly attributed to the amplifled temperature difference between ocean and land due to vegetation change. Thus, it would be given more attention to the impacts of LUCs on regional climate change. 相似文献
923.
Land scarcity has become the prominent obstacle on the way to sustainable development for China. Under the constraints of land shortage, how to allocate the finite land resources to the multiple land users in China considering various political, environmental, ecological and economic conditions have become research topics with great significance. In this study, an interval fuzzy national-scale land-use model(IFNLM) was developed for optimizing land systems of China. IFNLM is based on an integration of existing interval linear programming(ILP), and fuzzy flexible programming(FFP) techniques. IFNLM allows uncertainties expressed as discrete interval values and fuzzy sets to be incorporated within a general optimization framework. It can also facilitate national-scale land-use planning under various environmental, ecological, social conditions within a multi-period and multi-option context. Then, IFNLM was applied to a real case study of land-use planning in China. The satisfaction degree of environmental constraints is between 0.69 and 0.97, the system benefit will between 198.25 × 1012 USD and 229.67 × 1012 USD. The results indicated that the hybrid model can help generate desired policies for land-use allocation with a maximized economic benefit and minimized environmental violation risk. Optimized land-use allocation patterns can be generated from the proposed IFNLM. 相似文献
924.
Coccolithophorid is unicellular marine microalgae with a global distribution in temperate and sub-temperate oceanic regions and has the ability to produce ‘the coccoliths'. It is considered to be the second most productive calcifying organism on earth and becoming an important factor in the global carbonate cycle. Emiliania huxleyi is one of the only two bloom-forming coccolithophores and becomes a species crucial to the study of global biogeochemical cycles and climate modeling. Coccolithoviruse is a recently discovered group of viruses infecting the marine coccolithophorid E. huxleyi. They are a major cause of coccolithophore bloom termination, and DMSP concentration is increasing in the process of viral lysis. Phylogenetic evidences support that some genes are functional both in E. huxleyi and its virus(Eh V). Horizontal gene transfer(HGT) of multiple functionally coupled enzymes occurs in E. huxleyi and its DNA virus Eh V has been confirmed, which contributes to the diversification and adaptation of plankton in the oceans and also critically regulates virus-host infection by allowing viruses to control host metabolic pathways for their replication. Therefore, it is of particular interest to understand this host-virus interaction. On this issue, we have made a minireview of coccolithoviruses focusing on the basic characteristics, phylogenesis, horizontal gene transfer and the interaction between the host and its viruses, as well as its important role in global biogeochemical cycling. 相似文献
925.
Recently, study in past trends of climate variables gained significant consideration because of its contribution in adaptions and mitigation strategies for potential future changes in climate, primarily in the area of water resource management. Future interannual and inter-seasonal variations in maximum and minimum temperature may bring significant changes in hydrological systems and affect regional water resources. The present study has been performed to observe past(1970-2010) as well as future(2011-2100)spatial and temporal variability in temperature(maximum and minimum) over selected stations of Sutlej basin located in North-Western Himalayan region in India. The generation of future time series of temperature data at different stations is done using statistical downscaling technique. The nonparametric test methods, modified Mann-Kendall test and Cumulative Sum chart are used for detecting monotonic trend and sequential shift in time series of maximum and minimum temperature. Sen’s slope estimator test is used to detect the magnitude of change over a period of time on annual and seasonal basis. The cooling experienced in annual TMax and TMin at Kasol in past(1970-2010) would be replaced by warming in future as increasing trends are detected in TMax during 2020 s and 2050 s and in TMin during 2020 s, 2050 s and 2080 s under A1 B and A2 scenarios. Similar results of warming are also predicted at Sunnifor annual TMin in future under both scenarios which witnessed cooling during 1970-2010. The rise in TMin at Rampur is predicted to be continued in future as increasing trends are obtained under both the scenarios. Seasonal trend analysis reveals large variability in trends of TMax and TMin over these stations for the future periods. 相似文献
926.
Spatial and Temporal Variability of Water Vapor Content during 1961-2011 in Tianshan Mountains,China
Based on the climate factors data and surface vapor pressure(SVP) data of 44 weather stations in Tianshan Mountains during the years 1961-2011, this paper establishes a water vapor content(WVC) estimation model according to the relationship between monthly WVC of radiosonde and corresponding SVP and analyzes the spatial and temporal variability of WVC and their causes. The results show that the WVC is linearly and negatively related to the elevation and longitude(Vertical zonality and Longitude zonality), while it was not linearly related to the latitude. The westerly wind, geographical situation and sea level elevation composed complex surface conditions to influence the spatial distribution of WVC in the Tianshan Mountains. The Mann-Kendall(M-K) statistical test shows a significant increasing trend in the mean annual WVC in Tianshan Mountains during 1961-2011(P 0.001), with a rate of 0.23 mm/decade, and indicates an abrupt turning point in 1985(P 0.001). Correlation analysis shows that the WVC are significantly correlated to the temperature, especially during the winter, but the summer WVC are significantly correlated to the precipitation. In addition, the North Atlantic Oscillation Index(NAOI)and the Arctic Oscillation Index(AOI) are significantly correlated to the winter WVC in the Tianshan Mountains. As a new Microwave radiometric profilers(MWRPs) instrument, the MP-3000 A provides continuous, real-time and high temporal resolution atmospheric profiles up to 10 km. In order to monitor water vapor and atmosphere profiles in Tianshan Mountains, an MP-3000 A was established in Urumqi(43.8°N, 87.58°N) in May 2008. The results indicated that the MP-3000 A was applicable to this area, and the evolutionary process of water vapor and the WVC peak values of MP-3000 A were a strong signal for rainstorm and flood forecasts for Urumqi and the Tianshan Mountains. 相似文献
927.
介绍了用格子玻尔兹曼方法模拟非均匀介质中的电场响应的数值模拟方法. 格子玻尔兹曼方法是从微观领域出发进行数值计算的一种全新的正演模拟方法;从玻尔兹曼碰撞模型出发,利用泰勒展开和Chapman Enskog展开,在基本力学守恒条件和约束条件的限制下,导出了电场响应的扩散方程,得到了局部平衡分布函数的表达式,给出了若干正演模拟的结果;其结果表明,利用这种方法进行非均匀介质中的电场响应正演模拟具有灵活、方便和简单等优点. 相似文献
928.
依据“建设用地地质灾害危险性评估技术要求”选择积分法对工程建设用地进行地质灾害危险性现状评估,结果认为:评估区的地质环境条件复杂程度属简单—中等类型,评估区现状地质灾害有崩塌灾害—种类型7处,属危险性小的级别,对其危险性起决定性作用的因素有:地形条件、地层岩性、构造与地震和人为活动。 相似文献
929.
建设用地地质灾害危险性评估中关键技术问题的探讨 总被引:6,自引:0,他引:6
根据“建设用地地质灾害危险性评估技术要求”中的原则,对建设项目(市政工程、铁路工程及其它)重要性进行了评估级别的划分。尝试确定了评估范围。提出危险性分区可根据评估区地质灾害危险性综合评价结果进行划分。 相似文献
930.