应用NOAA/AVHRR资料监测水稻长势的研究   总被引：6，自引：1，他引：5  

石宇虹  李国春 《应用气象学报》1999,10(2):243-248

该文利用1992～1996年NOAA/AVHRR资料,结合实测的地面农作物生长发育农学参数,系统地分析了沈阳市水稻移栽至收获整个本田期间遥感归一化植被指数（NDVI）的变化规律,进而达到对沈阳市水稻长势遥感动态监测的目的。  相似文献   

广西中部二叠系乐平统层序地层研究   总被引：10，自引：0，他引：10  

梅仕龙  朱自力 《现代地质》1999,13(1):11-18

通过对分别位于台地、斜坡和盆地的广西合山马滩剖面、来宾铁桥剖面和来宾蓬莱滩剖面的廊带式追索研究,将二叠系乐平统地层自下而上划分为Ｌｐ１、Ｌｐ２、Ｌｐ３、Ｌｐ４、Ｌｐ５和Ｌｐ６６个三级层序,并建立了相应的海平面变化曲线。结合原有和最新的生物地层资料,对这３个剖面的层序地层划分实现了精确对比,从而将原有地层对比精度提高了１倍。主张以牙形石Ｃｌａｒｋｉｎａｓｕｂｃａｒｉｎａｔａ的初现作为长兴阶和吴家坪阶的分界,这一界线与上述三级层序Ｌｐ６的首次海泛面一致。长期被当作长兴阶下部带化石的Ｇａｌｏｗａｙｉｎｅｌａｍｅｉｔｉｅｎｅｎｓｉｓ和Ｐａｌａｅｏｆｕｓｕｌｉｎａｍｉｎｉｍａ可向下延入依据牙形石定义的吴家坪阶。  相似文献   

安徽宣城茶亭铜金矿床隐爆角砾岩特征及其成矿意义     

谢巧勤  孙锐  徐晓春  许心悦  安昱华  钱仕龙 《高校地质学报》2020,26(3):255-264

安徽宣城茶亭铜金矿床是近年来在长江中下游浅覆盖区之南陵—宣城中—新生代火山—沉积盆地中新发现的一个大型矿床。文章以赋矿石英闪长玢岩侵入体内发育的隐爆角砾岩为对象,通过详细的钻孔岩心观察和显微岩相学研究,确定其地质特征并探讨其与成矿的关系。根据钻孔岩心观察确定的岩石构造特征及钻孔剖面圈定的角砾岩空间分布特征,茶亭铜金矿床发育的隐爆角砾岩呈上大下小的不规则筒状体,被隐伏的石英闪长玢岩侵入体包孕。根据角砾特征以及角砾间的裂隙和胶结物特征,可将隐爆角砾岩划分为隐爆浆屑角砾岩、隐爆热液角砾岩和隐爆破裂角砾岩三类,三类隐爆角砾岩空间上有规律地分布,以隐爆浆屑角砾岩为中心向外或向上依次过渡为隐爆热液角砾岩→隐爆破裂角砾岩→石英闪长玢岩。基于隐爆角砾岩与蚀变和矿化的关系推测,岩浆—气液隐蔽爆破作用所产生的大量裂隙为后期含矿岩浆热液和大气降水热液的运移、交代、混合乃至卸载、沉淀成矿提供了有利的构造空间。茶亭铜金矿床的矿体赋存于浅成斑岩侵入体中,其围岩蚀变类型与分带,以及矿化呈细粒浸染状和细脉—网脉状等地质特征显示其与斑岩型矿床极为相似,但矿化富集部位与隐爆角砾岩筒（体） 的一致,且矿床同时发育角砾状、脉状、团块状矿化,矿脉中发育热液硬石膏甚至形成硬石膏岩等地质特征又明显不同于斑岩型矿床。因此,文章将茶亭铜金矿床确定为一个与中酸性浅成斑岩侵入体密切相关的隐爆角砾岩型矿床。  相似文献   

吉林省1：20万区域化探一些矿致异常的分散模式     

朴清龙 《吉林地质》1993,12(1):16-25

在《吉林省1∶20万水系沉积物地球化学异常筛选研究》工作中,对省内五个典型矿床地球化学异常进行了剖析性研究。本文以其中某已知铜金矿床区域性异常为例,论述了矿致的水系沉积物地球化学异常的基本特征和分散模式,进一步阐述了水系沉积物地球化学找矿模式及找矿远景预测。  相似文献   

Does the integration of the dynamic nitrogen cycle in a terrestrial biosphere model improve the long-term trend of the leaf area index?     

B. Guenet  P. Cadule  S. Zaehle  S. L. Piao  P. Peylin  F. Maignan  P. Ciais  P. Friedlingstein 《Climate Dynamics》2013,40(9-10):2535-2548

The carbon cycle strongly interacts with the nitrogen cycle. Several observations show that the effects of global change on primary production and carbon storage in plant biomass and soils are partially controlled by N availability. Nevertheless, only a small number of terrestrial biosphere models represent explicitly the nitrogen cycle, despite its importance on the carbon cycle and on climate. These models are difficult to evaluate at large spatiotemporal scales because of the scarcity of data at the global scale over a long time period. In this study, we benchmark the capacity of the O–CN global terrestrial biosphere model to reproduce temporal changes in leaf area index (LAI) at the global scale observed by NOAA_AVHRR satellites over the period 1982–2002. Using a satellite LAI product based on the normalized difference vegetation index of global inventory monitoring and modelling studies dataset, we estimate the long-term trend of LAI and we compare it with the results from the terrestrial biosphere models, either with (O–CN) or without (O–C) a dynamic nitrogen cycle coupled to the carbon–water-energy cycles. In boreal and temperate regions, including a dynamic N cycle (O–CN) improved the fit between observed and modeled temporal changes in LAI. In contrast, in the tropics, simulated LAI from the model without the dynamic N cycle (O–C) better matched observed changes in LAI over time. Despite differential regional trends, the satellite estimate suggests an increase in the global average LAI during 1982–2002 by 0.0020 m² m^?2 y^?1. Both versions of the model substantially overestimated the rate of change in LAI over time (0.0065 m² m^?2 y^?1 for O–C and 0.0057 m² m^?2 y^?1 for O–CN), suggesting that some additional limitation mechanisms are missing in the model. We also estimated the relative importance of climate, CO₂ and N deposition as potential drivers of the temporal changes in LAI. We found that recent climate change better explained temporal changes in LAI when the dynamic N cycle was included in the model (higher ranked fit for O–CN vs. O–C). Using the O–C configuration to estimate the direct effect of climate on LAI, we quantified the importance of climate-N cycle feedbacks in explaining the LAI response. We found that the warming-induced release of N from soil organic matter decomposition explains 17.5 % of the global trend in LAI over time, however, reaching up to 40.9 % explained variance in the boreal zone, which is a more important contribution than increasing anthropogenic nitrogen deposition. Our analysis supports a strong connection between warming, N cycling, and vegetation productivity. These findings underscore the importance of including N cycling in global-scale models of vegetation response to environmental change.  相似文献   

Development of coastal erosion and management     

LOU Shilong  Cai Feng  Wang Houjie 《地球科学进展》2013,28(11):1239-1247

Coastal erosion and management attract much conern all around the world as coastal erosion is a problem at many coastal sites exacerbated by human activities and its adaptability through reasonable mitigation measures. This paper summarizes the main factors causing coastal erosion including reduction of sediment discharged by rivers trapped coastal structures, sand mining and reclaimation, relative sea-level rise, destruction of coastal ecosystem and weakening of coastal defenses. Mechanisms causing erosion of coastal dune, soft rock coast and muddy coast are identified and discussed. Sandy coastal erosion, soft rock coastal erosion, muddy coastal erosion, biological coastal erosion and coastal structural erosion are identified according to the characteristics of erosion in China. This study supplements the theory and methodology for coastal erosion management and provides information for managers and stakeholders.  相似文献   

下扬子巢湖地区鼓地1井五峰组-高家边组下段页岩地球化学特征及其地质意义     

薛路  陈建文  吴飘  张鹏辉  王拔秀 《海洋地质前沿》2022,38(5):12-22

  相似文献   

Recognizing the Scientific Mission of Flux Tower Observation Networks—Lay the Solid Scientific Data Foundation for Solving Ecological Issues Related to Global Change     

YU Guirui  CHEN Zhi  ZHANG Leiming  PENG Changhui  CHEN Jingming  PIAO Shilong  ZHANG Yangjian  NIU Shuli  WANG Qiufeng  LUO Yiqi  CIAIS Philippe  BALDOCCHI D. Dennis 《资源与生态学报(英文版)》2017,8(2):115-120

As the Earth entering into the Anthropocene, global sustainable development requires ecological research to evolve into the large-scale, quantitative, and predictive era. It necessitates a revolution of ecological observation technology and a long-term accumulation of scientific data. The ecosystem flux tower observation technology is the right one to meet this requirement. However, the unique advantages and potential values of global-scale flux tower observation are still not fully appreciated. Reviewing the development history of global meteorological observation and its scientific contributions to the society, we can get an important enlightenment to re-cognize the scientific mission of flux observation.  相似文献   

四川盆地上三叠统须家河组高分辨率层序地层研究     

谭聪  于炳松  阮壮  郝士龙  李琨  罗忠  刘润达 《现代地质》2017,31(2):290

为了进一步认识四川盆地须家河组的层序格架和时空分布,基于高分辨率层序地层学及沉积学相关理论,通过露头剖面、钻井岩心的观察及测井、地震等资料的分析,开展了四川盆地须家河组层序地层研究,结果发现盆地内虽然具有构造复杂、物源多样、岩相不均、组名不统一的特点,但依然具有全盆地范围内可追溯的不整合面和湖泛面。通过层序界面追踪及沉积旋回分析,将四川盆地须家河组划分为3个超长期基准面旋回、6个长期基准面旋回及21个中期基准面旋回,并建立了盆地内各级旋回的对比关系。通过全盆地对比结果表明,须家河组在南北方向上各级旋回个数变化不大,沉积厚度相对稳定;东西方向上旋回变化复杂,西部缺失LSC6旋回和大部分LSC5旋回,东部则缺失大部分LSC1旋回,由于沉降与沉积中心位于龙门山前缘坳陷,盆地近西部沉积速率极高,整体的沉积体展布呈现西厚东薄的楔形体形态特征。在层序对比研究的基础上,尝试性地建立了年代地层格架,通过层序地层学与年代地层学、古生物地层学的综合对比,推测了各旋回的相对年龄值以及不整合面的沉积间断时间,为四川盆地须家河组下一步油气资源探勘开发提供了理论支持。  相似文献   

Perfectly matched layer for an elastic parabolic equation model in ocean acoustics     

Chuanxiu Xu  Haigang Zhang  Shengchun Piao  Shi’e Yang  Sipeng Sun  Jun Tang 《中国海洋大学学报(英文版)》2017,16(1):57-64

The perfectly matched layer(PML) is an effective technique for truncating unbounded domains with minimal spurious reflections. A fluid parabolic equation(PE) model applying PML technique was previously used to analyze the sound propagation problem in a range-dependent waveguide(Lu and Zhu, 2007). However, Lu and Zhu only considered a standard fluid PE to demonstrate the capability of the PML and did not take improved one-way models into consideration. They applied a [1/1] Padé approximant to the parabolic equation. The higher-order PEs are more accurate than standard ones when a very large angle propagation is considered. As for range-dependent problems, the techniques to handle the vertical interface between adjacent regions are mainly energy conserving and single-scattering. In this paper, the PML technique is generalized to the higher order elastic PE, as is to the higher order fluid PE. The correction of energy conserving is used in range-dependent waveguides. Simulation is made in both acoustic cases and seismo-acoustic cases. Range-independent and range-dependent waveguides are both adopted to test the accuracy and efficiency of this method. The numerical results illustrate that a PML is much more effective than an artificial absorbing layer(ABL) both in acoustic and seismo-acoustic sound propagation modeling.  相似文献