三峡库区山区农业生态系统转型     

梁鑫源  李阳兵  邵景安  冉彩虹 《地理学报(英文版)》2020,30(2):281-296

The Three Gorges Reservoir Area(TGRA)is typical of an ecologically vulnerable area,comprised of rural and mountainous areas,and with high immigration.Because of its economic and ecologic importance,studying the traditional agroecosystem changes in the TGRA is key to rural development and revitalization.In this study,we apply a framework of theoretical analysis,empirical study,and trend prediction to the Caotangxi River watershed within the TGRA.Using QuickBird high-resolution remote sensing images from 2012 to 2017 to evaluate natural resources and farmers’behavior,we analyze the transition and trends in the traditional agroecosystem in mountainous areas of the TGRA at spatial scale of the man-land relationship.We find that the agroecosystem in the TGRA can be divided into four modes using 100 m interval buffer rings:high-low-low,high-low-high,low-high-low and low-low-high mode where the different modes represent the agricultural development stages in the TGRA.Furthermore,the traditional agroecosystem in TGRA,represented by system elements such as farmers and sloping farmland,is transforming to accommodate the diversification of farmer livelihoods.For example,sloping farmland,which was dominated by a production function,now has equal emphasis on ecological and economic functions.Spatially,the range of the agroecosystem transition has migrated beyond high mountain areas to flat valley areas.Generally,this study provides an overview of land use in rural areas,controls on soil and water loss in mountainous areas,and better rural living environments in the TGRA.  相似文献   

A Coupling Method for Eco-Geological Environmental Safety Assessment in Mining Areas Using PCA and Catastrophe Theory     

Sun  Xiaofei  Shao  Huaiyong  Xiang  Xiaoyu  Yuan  Linguo  Zhou  Yingzhi  Xian  Wei 《Natural Resources Research》2020,29(6):4133-4148

Natural Resources Research - Most mineral resources in China are located in the areas with fragile geologic environment, where long-term irrational exploitation of mineral resources has caused...  相似文献   

基于GF-4卫星的杭州湾悬浮泥沙浓度遥感监测研究     

邵宇杰  胡越凯  周斌  陈芳  何贤强  王国军  袁小红  周亚丽  于之锋 《海洋学报》2020,42(9):134-142

悬浮泥沙作为重要水质参数,其分布和动态变化对河口及近岸的生态、环境、物质循环等都具有深远的影响。我国静止轨道高分四号(GF-4)卫星数据具有高时间和高空间分辨率的观测优势,在水色遥感上具有重大应用潜力。为探究GF-4卫星对悬浮泥沙浓度的监测能力,本文以杭州湾为研究区,构建反演模型,利用静止海洋水色成像仪进行交叉验证。结果表明,以GF-4卫星第5和第4波段遥感反射率的比值作为遥感因子建立的反演模型精度较高,决定系数为0.92,均方根误差为223.2 mg/L,平均相对误差为17.2%。交叉验证结果显示,GF-4卫星作为一种新的遥感数据源,在低浓度区与静止海洋水色成像仪反演悬浮泥沙浓度分布相似,但在高浓度区的差异随浓度增高而增大,总体可满足中国大部分海区的监测需求。  相似文献   

利用WSBV的引物扩增中国对虾的杆状病毒DNA     

汪岷  苏冬梅  包振民  邵济钧  戴继勋 《中国海洋大学学报(自然科学版)》1998,(4)

利用台湾报道的ＷＳＢＶ的ＰＣＲ引物,成功地扩增出了１４００ｂｐ左右的中国对虾的杆状病毒的ＤＮＡ片段,与预计的产物长度吻合。该引物对经初步离心处理的病虾组织也能扩增出特异性ＤＮＡ条带,而对正常虾组织ＤＮＡ、昆虫杆状病毒（ＡｃＭＮＰＶ）ＤＮＡ进行扩增,均获得阴性结果。说明该引物的特异性较高,对中国对虾的杆状病毒的检测具有一定的实际应用价值。实验结果同时说明ＷＳＢＶ与中国对虾的杆状病毒有同源序列存在,具有一定的保守性;用该引物进行的ＰＣＲ扩增为中国对虾的杆状病毒与其他相关病毒的比较研究提供了一种技术手段。  相似文献   

On the Choice of Soil Hydraulic Models in Land-Surface Schemes   总被引：9，自引：0，他引：9  

Yaping Shao  Parviz Irannejad 《Boundary-Layer Meteorology》1999,90(1):83-115

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Numerical Modelling of Saltation in the Atmospheric Surface Layer     

Yaping Shao  An Li 《Boundary-Layer Meteorology》1999,91(2):199-225

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WSR-88D多普勒天气雷达的运行设计和使用情况分析   总被引：1，自引：0，他引：1  

黄炎  邵玲玲  葛张全 《气象》1999,25(5):13-18

介绍了上海市气象局ＷＳＲ－８８Ｄ型多普勒天气雷达的架设,通信传输,系统数据流,产品的获取方式,雷达可调参数设置等运行设计,并例举了１９９８年的三个应用实例,表明ＷＳＲ－８８Ｄ对强风暴具有很强的探测能力,通过对风暴的结构和多普勒风场连续演变的分析,在强风暴的短时预报中发挥了明显的作用。  相似文献   

广西来宾-合山一带晚二叠世海底扇浊积岩相   总被引：11，自引：6，他引：5       下载免费PDF全文

邵龙义  张鹏飞 《古地理学报》1999,1(1):20-31

广西来宾蓬莱滩及合山马滩两地的晚二叠世地层中发育有典型的重力流沉积构造,如粒序层理、包卷层理、槽模、重荷模、碟状构造和滑塌褶皱等。通过对蓬莱滩合山组和大隆组以及马滩剖面的大隆组岩相特征的详细研究,提出来宾蓬莱滩晚二叠世合山组和大隆组以及合山马滩晚二叠世大隆组形成于海底扇环境,划分出具碟状构造的块状砂岩(B１)、块状砂岩(B2)、近基浊积岩(C)、远基浊积岩(D)、不规则互层的砂泥岩(E)、滑塌褶皱层(F)及含浮游生物化石的页岩、硅质岩(G)等岩相类型,同时归纳出外扇相组合、中扇舌状体相组合、中扇水道相组合、斜坡相组合及深切谷水道相组合等,还对这些海底扇浊积岩系的古地理意义做了讨论。桂中碳酸盐岩台地相区和云开古陆之间在晚二叠世为一发育海底扇浊积岩的深水盆地,其中来宾-合山一带在大隆组沉积期处于水深约300～1 000 m的深水盆地环境,合山一带火山活动提供的火山物质及来自东侧云开古陆的陆源物质构成该区浊积岩的主要物源。  相似文献   

STUDY ON THE PHYSICAL PROCESS OF WINTER VALLEY FOG IN XISHUANGBANNA REGION^*          下载免费PDF全文

Li Zihu  Huang Jianping  Huang Yusheng  Yang Zhiyong  Wang Qiang 《Acta Meteorologica Sinica》1999,13(4):494-508

Xishuangbanna of Yunnan Province is a famous tropical foggy region.A field experiment was carried out from November 23 to 30 of 1997 during which fogs occurred regularly every day.In the paper the characteristics of macrostructure of fog are analyzed and the physical processes of formation and dissipation of fog are studied.The results show that the Xishuangbanna valley fog forms firstly in the lower atmosphere with two-layer structures and then develops suddenly in the vertical direction after reaching the ground.Furthermore,the vegetation effect on the formation and dissipation of fog is discussed specially.  相似文献   

Expression of Mammalian Metallothionein-I Gene in Cyanobacteria to Enhance Heavy Metal Resistance   总被引：2，自引：0，他引：2  

Z.Chen  L. Ren  Q. Shao  D. Shi  B. Ru 《Marine pollution bulletin》1999,39(1-12):155-158

Metallothionein (MT) from mammals is a low molecular weight (about 6–7 KD), and cystein-rich (20 cystein per molecular) protein (Vallee, 1991). So MT has the strong binding ability of metal such as Cd, Hg and Pd. Wild-typed cyanobacteria have their own metallothionein-like proteins, which are of low cysteine content and have weak ability to bind heavy metal. Therefore, it is imperative to transfer the MT-I gene from mammal into cyanobacteria cell for the absorption and accumulation of heavy metals in aqueous system including marine and lake ( Misra and Gedamu, 1989). We inserted the MT-I cDNA gene after the strong promoter PpsbA or Psmt into the intermediary vector pRL-439, and then pRL-MT was ligated with shuttle vector pKT-210 (a shuttle vector pDC-08 was used at an earlier time) to construct the shuttle expression vector pKT-MT. (The MT-I mutant -KKS- also was selected as aim gene.) Then the constructed vector was introduced into cyanobacterium Anabaena sp. PCC7120, Synechocystis sp. PCC6803 and Synechococcus sp. PCC7942 with triparental conjunctive transfer (Bryant, 1994). The expression efficiency is about 1%. We also used homologous recombination vector pTZ18-8 to introduce MT-I cDNA into chromosomes in cyanobacteria and got higher expression efficiency. Metal tolerance tests show that the transgenic cyanobacteria acquire metal resistance up to 60 μmol/g CdCl₂ and expression efficiency up to 1045 μg MT/g fresh cells according to the data of ELISA.  相似文献