Changes of urban wetland landscape pattern and impacts of urbanization on wetland in Wuhan City   总被引：2，自引：1，他引：2  

WANG Xuelei NING Longmei YU Jing XIAO Rui LI Tao 《中国地理科学(英文版)》2008,18(1):47-53

In this study, remote sensing data of Wuhan City,, Hubei Province, China in 1996-2001 were selected to extract wetland landscape information. Several landscape indices were used to evaluate the changes of landscape pattern within the five years, including patch number, patch density, patch fractal dimension, landscape diversity, dominance, evenness, and fragmentation indexes. Then, transformation probabilities of wetland landscapes into non-wetland landscapes were calculated based on Markov Model, and on these grounds the relationship between changes of wetland landscape pattern and urban construction was analyzed. The results showed that fragmentation degree of all wetland types increased, lake area declined, and dominance of natural wetland decreased. The reasons for these results were mainly because of urban construction. According to the features of abundant wetland in Wuhan City, we suggested that protection of wetland landscape should cooperate with urban construction, which means wetland should become important part of urban landscape.  相似文献   

Lateral bearing characteristics of subsea wellhead assembly in the hydrate trial production engineering     

Jing Zeng  Wen-wei Xie  Bei-bei Kou  Jing-an Lu  Xing-chen Li  De-jun Cai  Hao-xian Shi  Ke-wei Zhang  Hua-qing Liu  Jin Li  Bo Li 《China Geology》2023,(3):455-465

Conductor and suction anchor are the key equipment providing bearing capacity in the field of deep-water drilling or offshore engineering, which have the advantages of high operation efficiency and short construction period. In order to drill a horizontal well in the shallow hydrate reservoir in the deep water,the suction anchor wellhead assembly is employed to undertake the main vertical bearing capacity in the second round of hydrate trial production project, so as to reduce the conductor runn...  相似文献   

应用雷达拼图数据估测降水试验     

伍静  刘黎平  尤卫红  崔哲虎 《海洋学研究》2010,(1)

利用2008年6月5～7日广东省新一代天气雷达网(广州、梅州、韶关、阳江、深圳及汕头6部雷达)的雷达原始体扫资料及自动雨量站资料,对广东省3 km高度上的雷达网系统观测值差异进行了分析,发现广州雷达的观测值比周围雷达偏高1～3 dBz,梅州雷达比其周围雷达的观测值偏低1～2 dBz。用Z-R关系和最优插值校准法分别进行6 min和1 h估测降水,并用面雨量偏差和均方根误差对该次降水估测试验做了简单评估。结果显示:6 min定量估测降水,两种方法都会低估,面雨量越大,估测效果越好;对于1 h定量估测降水,各种估测方法都有偏高或偏低情况,但普遍偏高,其中用先累加再用最优插值校准法校准的雷达-雨量计联合估测方法效果最好;短时降水估测可以很好地反映降水过程变化,而长时间降水估测可以较准确估测降水大小。  相似文献   

Spatial Variation and Risk Assessment of Arsenic and Heavy Metals in Surface Water and Suspended Particulate Matter in Tail Reaches of the Yellow River,China     

SUN Zhigao  LI Jing  TIAN Liping  CEHN Bingbing  HU Xingyun 《中国地理科学(英文版)》2021,(1):181-196

To determine the pollution levels and potential toxic risks of arsenic(As) and heavy metals(Cr, Ni, Cu, Zn, Pb and Cd) in water and suspended particulate matter(SPM) in tail reaches(including freshwater reach and low-salinity reach) of the Yellow River as the Flow-Sediment Regulation Project(FSRP) has been carried out for approximately 15 yr, the surface water and SPM were sampled at pre-flood(April) and post-flood seasons(October). Results showed that similar changes of As and metal levels in water and SPM were observed along the tail reaches at pre-flood or post-flood season. Compared to pre-flood season, the levels of As, Cu, Cr and Ni in freshwater reach and the concentrations of Cr and Ni in low-salinity reach rose greatly at post-flood season. The levels of As and metals in SPM of freshwater reach or low-salinity reach at pre-flood season were significantly higher than those at post-flood season(P < 0.01).The pollutions of As and metals in surface water of tail reaches at pre-flood or post-flood season were not serious. The SPM in freshwater reach at pre-flood season were polluted by Cd, As, Cr, Cu and Ni while those in low-salinity reach were polluted by Cd and Cr. The SPM in freshwater reach at post-flood season were polluted by Cd and Pb while those in low-salinity reach were polluted by Cd and Cr.Cd was identified as heavy metal of primary concern at both pre-flood and post-flood seasons. Combined with the existed data reported in present research, this study found that the toxic risk of As and metals in SPM of tail reaches at pre-flood season was higher than that at post-flood season, implying that the implementation of FSRP during flooding season, to a great extent, reduced the toxic risk of these elements. With the long-term implementation of FSRP, the pollution levels of As and metals(particularly for Cd) in SPM of tail reaches might be elevated and the potential toxic risk primarily produced by Cr, Ni and As might be increased if effective measures were not taken in future.  相似文献   

Integrative analysis of transcriptomic profile reveals potential roles of miRNAs in regulating development of Marsupenaeus japonicas     

Jing WANG  Longjun PU  Xiaojuan ZHANG  Cuicui LIANG  Dandan DONG  Jiantao GUAN  Huarong GUO 《海洋湖沼学报（英文）》2024,(1):201-215

  相似文献   

Discussion on the Seismic Intensity of the Hutubi MS6.2 Earthquake on December 8, 2016     

Luo Ju  Chen Jianbo  Chang Xiangde  Li Shuai  Sun Jing  Yao Yuan 《中国地震研究》2017,31(3):360-367

Based on the field investigation of 182 seismic hazard survey sites,combined with analysis of the aftershock sequence, focal mechanism, and seismo-tectonic background, we produced the seismic intensity map of the Hutubi M_S6.2 earthquake. The seismic intensity of the magistoseismic area is degree Ⅷ,with the orientation of long axis of isoseismic contour lines east-west. The Qingshuihezi fault is considered as the seismogenic fault of Hutubi M_S6.2 earthquake  相似文献   

Deformation Evolution Characteristics Revealed by GPS and Cross-fault Leveling Data before the MS8.0 Wenchuan Earthquake     

ZHAO Jing  LIU Jie  REN Jinwei  YUE Chong  LI Jiaojiao 《中国地震研究》2019,33(3):461-477

Based on GPS velocity during 1999-2007, GPS baseline time series on large scale during 1999-2008 and cross-fault leveling data during 1985-2008, the paper makes some analysis and discussion to study and summarize the movement, tectonic deformation and strain accumulation evolution characteristics of the Longmenshan fault and the surrounding area before the M_S8.0 Wenchuan earthquake, as well as the possible physical mechanism late in the seismic cycle of the Wenchuan earthquake. Multiple results indicate that:GPS velocity profiles show that obvious continuous deformation across the eastern Qinghai-Tibetan Plateau before the earthquake was distributed across a zone at least 500km wide, while there was little deformation in Sichuan Basin and Longmenshan fault zone, which means that the eastern Qinghai-Tibetan Plateau provides energy accumulation for locked Longmenshan fault zone continuously. GPS strain rates show that the east-west compression deformation was larger in the northwest of the mid-northern segment of the Longmenshan fault zone, and deformation amplitude decreased gradually from far field to near fault zone, and there was little deformation in fault zone. The east-west compression deformation was significant surrounding the southwestern segment of the Longmenshan fault zone, and strain accumulation rate was larger than that of mid-northern segment. Fault locking indicates nearly whole Longmenshan fault was locked before the earthquake except the source of the earthquake which was weakly locked, and a 20km width patch in southwestern segment between 12km to 22.5km depth was in creeping state. GPS baseline time series in northeast direction on large scale became compressive generally from 2005 in the North-South Seismic Belt, which reflects that relative compression deformation enhances. The cross-fault leveling data show that annual vertical change rate and deformation trend accumulation rate in the Longmenshan fault zone were little, which indicates that vertical activity near the fault was very weak and the fault was tightly locked. According to analyses of GPS and cross-fault leveling data before the Wenchuan earthquake, we consider that the Longmenshan fault is tightly locked from the surface to the deep, and the horizontal and vertical deformation are weak surrounding the fault in relatively small-scale crustal deformation. The process of weak deformation may be slow, and weak deformation area may be larger when large earthquake is coming. Continuous and slow compression deformation across eastern Qinghai-Tibetan Plateau before the earthquake provides dynamic support for strain accumulation in the Longmenshan fault zone in relative large-scale crustal deformation.  相似文献   

Geochronological and geochemical constraints on the petrogenesis of late Mesoproterozoic mafic and granitic rocks in the southwestern Yangtze Block     

Guichun Liu  Jing Li  Xin Qian  Qinglai Feng  Wei Wang  Guangyan Chen  Shaobin Hu 《地学前缘(英文版)》2021,12(1):39-52

Late Mesoproterozoic igneous rocks in the SW Yangtze Block are important for understanding the role of it in reconstruction of the Rodinia supercontinent.In the present study,we report new geochronological,geochemical,and Nd-Hf isotopic data for the Cuoke plagioclase amphibolites and granites in the SW Yangtze Block.Geochronological results show that the plagioclase amphibolites and granites have similar late Mesoproterozoic zircon U-Pb ages of 1168-1162 Ma,constituting a bimodal igneous assemblage.The plagioclase amphibolites have high and variable TiO2 contents(1.15-4.30 wt.%)and Mg#(34-66)values,similar to the tholeiitic series.They are characterized by enrichment in LREEs and LILEs,and have OIB-like affinities with positive Nb and Ta anomalies.The plagioclase amphibolites have positive whole-rockεNd(t)(+3.2 to+4.3)and zirconεHf(t)(+4.3 to+10.7)values,indicating that they were derived from an OIB-like asthenospheric mantle source.The granites belong to the reduced peralkaline A-type series and have negativeεNd(t)value of-6.0 andεHf(t)values of-5.8 to-13.8,indicating a derivation from the partial melting of ancient mafic lower crust.In combination with the~1.05-1.02 Ga bimodal igneous assemblage in the SW Yangtze Block,we propose that the Cuoke 1168-1162 Ma igneous rocks were likely formed in a continental rift basin and argue against the existance of Grenvillian Orogen in the SW Yangtze Block during the late Mesoproterozoic.  相似文献   

Establishment of an astronomical time scale for the Shizigou Formation in the Qaidam Basin,Inner Asia and orbital forced evolution of lakes during The Pliocene     

DunZhu JiaoBa  MingZhen Zhang  GuoLong Liu  JianGuo Hui  ShaoHua Lin  AiJing Li  Jing Zhang  Jing Peng  YiQiao Fu 《寒旱区科学》2023,(5):239-252

The Qaidam Basin, as the largest inland basin within the Tibetan Plateau, has accumulated more than 10,000 m of Cenozoic continental sediments. It serves as a crucial research area for documenting Cenozoic climate changes and plateau uplift processes in the Asian interior. Additionally, the basin holds vast reserves of oil and gas resources, making high-resolution drilling data invaluable for studying paleoclimate. In this study, the longsequence lacustrine deposits of JS1 drill core across the ...  相似文献   

Pulsar Candidate Classification Using a Computer Vision Method from a Combination of Convolution and Attention     

Nannan Cai  Jinlin Han  Weicong Jing  Zekai Zhang  Dejiang Zhou  Xue Chen 《天文和天体物理学研究(英文版)》2023,(10):194-202

Artificial intelligence methods are indispensable to identifying pulsars from large amounts of candidates. We develop a new pulsar identification system that utilizes the CoAtNet to score two-dimensional features of candidates, implements a multilayer perceptron to score one-dimensional features, and relies on logistic regression to judge the corresponding scores. In the data preprocessing stage, we perform two feature fusions separately, one for one-dimensional features and the other for two-di...  相似文献