中纬度亚洲现代间冰期气候变化的“西风模式”讨论   总被引：6，自引：0，他引：6       下载免费PDF全文

陈发虎  陈建徽  黄伟 《地学前缘》2009,16(6):23

中纬度亚洲地区存在主要受季风环流影响的东南部湿润地区(简称季风区)和主要受西风环流控制的内陆干旱区(包括青藏高原北部高寒干旱区,简称西风区)。根据对近年来新发表的气候变化记录证据梳理总结,发现西风区在中—晚全新世气候湿润,与亚洲季风在早—中全新世强盛的格局显著不同。过去千年的西风区中世纪暖期干旱,而小冰期相对湿润,与此相对,万象洞石笋氧同位素记录则显示季风降水在中世纪暖期时整体处于高值,在小冰期处于低值段。在近百年,尤其是近50a,西北干旱区湿度增加,而季风影响范围内的西北东部和华北等地变得更干。不仅如此,在分属西风和季风影响区的青藏高原北部和南部,年代际—百年尺度上降水变化也表现出反相位关系。据此我们提出,亚洲中部西风带控制区在现代间冰期从数千年到年代际的各个时间尺度上均存在不同于季风区的湿度(降水)变化模式,称之为现代间冰期气候变化的西风模式。  相似文献   

Environmental magnetic studies of sediment cores from Gonghai Lake: implications for monsoon evolution in North China during the late glacial and Holocene   总被引：3，自引：0，他引：3  

Fahu Chen  Jianbao Liu  Qinghai Xu  Yuecong Li  Jianhui Chen  Haitao Wei  Qingsong Liu  Zongli Wang  Xianyong Cao  Shengrui Zhang 《Journal of Paleolimnology》2013,49(3):447-464

Environmental magnetic studies were conducted on a 9.42-m-long sediment core from Gonghai Lake, North China. Radiocarbon dating indicates that the record spans the last 15,000 cal year BP. The principal magnetic mineral in the sediments is pseudo-single domain magnetite of detrital origin with minimal post-depositional alteration. Although the variations in the concentration of detrital magnetic minerals and their grain size throughout the core reflect inputs from both soil erosion and eolian dust, it is shown that their climatic and environmental significance changes with time. In the lowermost part of the core, ~15,000–11,500 cal year BP, the magnetic minerals were supplied mainly by bedrock erosion, soil erosion and dust input when climate ameliorated after the cold and dusty last glacial maximum. The increasing magnetic susceptibility (χ) in this interval may indicate a combination of changes in the lake environment together with catchment-surface stabilization and a decreasing proportion of dust input. In the central part of the core, ~11,500–1,000 cal year BP, the detrital magnetic minerals mainly originated from dust inputs from outside the catchment when the lake catchment was covered by forest, and catchment-derived sediment supply (and thus the lake sediment accumulation rate) were minimal. The generally low concentration of magnetic minerals in this part of the core reflects the highest degree of soil stability and the strongest summer monsoon during the Holocene. In the uppermost part of the core, the last ~1,000 years, detrital magnetic minerals mainly originated from erosion of catchment soils when the vegetation cover was sparse and the sediment accumulation rates were high. Within this part of the core the high magnetic susceptibility reflects strong pedogenesis in the lake catchment, and thus a strong summer monsoon. This scenario is similar to that recorded in loess profiles. Overall, the results document three main stages of summer monsoon history with abrupt shifts from one stage to another: an increasing and variable summer monsoon during the last deglacial, a generally strong summer monsoon in the early and middle Holocene and a weak summer monsoon in the late Holocene. The results also suggest that different interpretational models may need to be applied to lake sediment magnetic mineral assemblages corresponding to different stages of environmental evolution.  相似文献   

福建永定大排铁铅锌多金属矿床地质特征及找矿模式探讨   总被引：2，自引：0，他引：2  

倪建辉 《福建地质》2012,(3):206-214

通过大量的野外地质调查,系统研究了永定县大排铁铅锌多金属矿床成矿地质背景和成矿作用、地质特征,分析了控矿地质条件,总结了找矿标志。认为大排铁铅锌多金属矿床为沉积-改造型矿床;控矿条件主要为晚石炭世经畲组至中二叠世楱霞组含矿层位及矿区内浅层次推覆构造;明确了含矿层位、控矿构造与容矿构造、岩浆岩、物化探异常、铁锰帽和古硐等作为找矿标志,结合区域其它矿床,建立该类矿床的找矿模式,以期指导闽西南地区铁铅锌多金属矿勘查工作。  相似文献   

Hydrodynamic Evolution and Hydrocarbon Accumulation in the Dabashan Foreland Thrust Belt,China   总被引：1，自引：0，他引：1  

ZENG Jianhui  GUO Kai  TIAN Kun  and XU Tianwu 《《地质学报》英文版》2012,86(4):912-923

There are two plays in the Dabashan foreland tectonic belt: the upper and the lower plays. The lower play experienced one sedimentary hydrodynamic stage, two burial hydrodynamic stages, two tectonic hydrodynamic stages and two infiltration hydrodynamic stages from the Sinian to the Cenozoic, while the upper play had one sedimentary hydrodynamic stage, one burial hydrodynamic stage, two tectonic hydrodynamic stages and one infiltration hydrodynamic stage from the Permian to the Cenozoic. Extensive flows of both sedimentary water, including hydrocarbons, and deep mantle fluid occurred in the Chengkou faults during collision orogeny in the Middle-Late Triassic Indosinian orogeny, and fluid flow was complicated during intracontinental orogeny in the Middle-Late Jurassic. In addition to these movements, infiltration and movement of meteoric water took place in the Chengkou faults, whereas in the covering-strata decollement tectonic belt, extensive sedimentary water flow (including hydrocarbons) occurred mainly in the Zhenba and Pingba faults. During the stage of rapid uplift and exhumation from the Cretaceous to the Cenozoic, the fluid flow was characterized mainly by infiltration of meteoric water and gravity-induced flow caused by altitude difference, whereas sedimentary water flow caused by tectonic processes was relatively less significant. Sedimentary water flow was more significant to the lower play in hydrocarbon migration and accumulation during collision orogeny in the Middle-Late Triassic Indosinian orogeny, but its influence is relatively slight on the upper play. On one hand, hydrodynamics during intracontinental orogeny in the Middle-Late Jurassic adjusted, reformed or oven destroyed oil reservoirs in the lower play; on the other hand, it drove large amounts of hydrocarbons to migrate laterally and vertically and is favorable for hydrocarbon accumulation. Infiltration hydrodynamics mainly adjusted and destroyed oil reservoirs from the Cretaceous to the Cenozoic.  相似文献   

Sobol’ sensitivity analysis of parameters in the common land model for simulation of water and energy fluxes     

Jianhui Xu  Hong Shu  Hongnan Jiang  Lin Dong 《Earth Science Informatics》2012,5(3-4):167-179

The water and energy transfer of land surface is complex due to its large spatial and temporal variability. The modeling and simulation is an important means to study land water and energy transfer, but most selection and analysis of model parameters are empirical and qualitative. This paper has proposed a method of quantitatively identifying the most influential parameters of Common Land Model through Sobol?? sensitivity analysis. Considering sensible heat flux as the model output, the first order and total sensitivity indices of 25 model input parameters are estimated using an improved Sobol?? method. The simulated results are resampled using a bootstrapping method and the corresponding sensitivity indices are calculated. Confidence intervals for the bootstrapping sensitivity indices are estimated by using a percentile method. The results show that the parameters phi0 and porsl are the most important parameters, followed by ref(2,1), tran(2,1) and bsw. Five out of 25 parameters need to have an accurate evaluation, while the other parameters are fixed to a certain value. The sensitivity indices of parameters phi0 and porsl are decreasing after precipitation, while the sensitivity indices of parameters tran(2, 1) and ref(2, 1) are increasing after precipitation.  相似文献   

基于ArcGIS Engine的插件式应用系统的实现     

施建辉 《测绘标准化》2011,(4):12-15

目前插件技术是软件开发的一种方式。以.NET C#为例,详细介绍实现插件式应用系统的原理和方法。根据这些原理和方法可扩展其功能,以实现一个实用的、功能强大的插件式应用系统,并简要介绍应用该方法实现的基于ArcGIS Engine的数字地图质量评价软件,该软件在实际应用中取得了较好的效果。  相似文献   

地震红外长波辐射短期异常特征分析     

李继业  任建辉  高峰  胡滨生  孟令蕾 《中国地震》2011,27(4):410-418

利用NOAA卫星资料反演的地震长波辐射值OLR对黑龙江及其周边2003年以来8次中强地震进行了追踪研究.结果显示,震前2个月左右OLR场值存在明显的高值异常区,未来震中距离高值区中心点250km(优势距离为160km).该方法对黑龙江及其周边4级以上地震短期判定可能具有一定的指示价值,也为利用卫星遥感技术预测未来可能发震区域并及时做出短期预测预警提供了新途径.  相似文献   

改革开放以来中国农业政策效果的时空计量分析   总被引：1，自引：0，他引：1  

余建辉  张文忠  王岱 《地理学报(英文版)》2011,21(3):475-488

Since reform and opening up, how much contribution has China’s implementation of new agricultural policy made to agricultural output? This paper is trying to establish an agricultural policy output econometric model for doing a quantitative analysis of China’s new agricultural policy. The results show that China’s agricultural policies on agricultural output have an average contribution rate of about 7% since 1978, which is consistent with the OECD’s basic forecast. There are obvious temporal and spatial differences. Generally speaking, we can divide the contribution of agricultural policy into three periods, which are the start-up phase from 1978 to 1991 (14 years), the stationary phase from 1992 to 2002 (11 years) and the rising phase from 2003 to 2008 (6 years). In space, the contribution of agricultural policy underwent a process from the all-low in the start-up phase, the gradual increase in the stationary phase to the all-high in the rising phase. Northern and western regions are more sensitive to policies. There are three major factors that can affect the contribution of regional agricultural policies, which are the process of national industrialization strategy, terrain and the level of local finance.  相似文献   

Multivariate analysis of heavy metal pollution in street dusts of Xianyang city, NW China   总被引：3，自引：2，他引：1  

Xingmin Shi  Lingxia Chen  Jianhui Wang 《Environmental Earth Sciences》2013,69(6):1973-1979

Urban street dust is one of important indicators of the status of urban environmental pollution. There are many studies in capital cities, but little attention has been paid to this kind of study in medium cities, especially in China. The dust samples were collected in the district of traffic crossroads in Xianyang city, Shaanxi Province. Pb, Cd, Cu, Ni, Zn, Cr and Mn concentrations were determined by using atomic absorption spectrometry. The results indicate that street dusts in Xianyang city have elevated metal concentrations as a whole in comparison with Shaanxi Province soil, except for Mn. The content of heavy metals was comparable to those in capital cities. Correlation coefficient analysis, principal component analysis and cluster analysis were used and three main sources were identified; Mn comes mainly from soil sources; Cu, Zn and Ni are mainly derived from industrial sources combined with traffic sources; Pb, Cr and Cd have traffic sources. Heavy metal enrichment factors were calculated, which can reflect human influence degree of street dusts.  相似文献   

地球系统多圈层构造观     

任纪舜  牛宝贵  徐芹芹  赵磊  刘建辉  李舢  朱俊宾  刘仁燕 《地质学报》2022,96(1):50-64

地球系统多圈层构造观的基本理论框架是:①把大地构造学从研究地球表层的地壳构造、岩石圈构造推进到研究地球整体多圈层构造的新阶段.②地球系统和宇宙天体系统共同作用下形成的全球动力学,太阳能、地球系统多圈层相互作用以及宇宙天体运行的联合作用是各种地质作用的动力来源.③洋陆转化论:陆与洋是对立统一、相互转化的.陆与洋都不会永存...  相似文献