山东省农村居民点转型的空间特征及其经济梯度分异   总被引：12，自引：2，他引：10  

曲衍波  姜广辉  张佰林  李慧燕  魏淑文 《地理学报》2017,72(10):1845-1858

为探究农村居民点转型的空间结构及其与经济发展的关联性,以山东省为例,基于农村宅基地转型的理论假设与测度方法,运用空间关联分析方法研究农村居民点转型的空间布局和集聚特征,并以人均GDP作为特征指标划分各县级行政区的经济发展梯度,从省级全域层面和“点、线、面”特征单元综合的角度,揭示农村居民点转型与经济发展的相关性及其耦合关系。结果显示,在空间分布上,2005-2014年山东省农村居民点转型指数呈现西高东低和南高北低的态势;在全局趋势上,Moran's I指数达到0.6317,说明农村居民点转型存在显著的空间集聚现象;在局部趋势上,农村居民点转型的热点区和次热点区集中分布在鲁西黄泛平原、鲁西南淮河平原以及鲁中沂蒙山区,次冷点区分布在次热点区外围,冷点区分布在胶东丘陵地区和鲁北黄河三角洲地带;在相关性分析上,农村居民点转型与经济发展水平具有明显的数理统计相关性和空间耦合性,无论是全域层面还是特征单元,农村居民点转型均表现出从低级到高级经济梯度的递减规律、且乘幂变化趋势显著。本文探索了农村居民点转型的空间特征,弥补了土地利用转型空间性分析的不足;同时研究结果也较好地验证了前人提出的理论假设。  相似文献   

民族文化资源的类型特征及成因分析——以格萨尔（果洛）文化生态保护实验区为例   总被引：2，自引：1，他引：1  

朱鹤  刘家明  桑子文  魏文栋  魏宗财 《地理学报》2017,72(6):1118-1132

由人类非物质文化遗产《格萨（斯）尔》史诗派生出的格萨尔文化是青藏高原地区独特的区域文化形态。文化资源是文化的载体和展示形式,具有价值性和不可替代性。研究格萨尔文化资源的分类、空间分布及成因对于探讨青藏高原地区人地关系,保护人类非物质遗产有非常重要的意义。果洛藏族自治州是格萨尔文化资源最为富集的区域,并于2014年被授予格萨尔文化生态保护实验区。本文首先对格萨尔文化资源进行界定和分类,并以果洛为例,探讨格萨尔文化资源的空间分布特征及与自然地理条件（高程、水源、坡度、坡向、可达性）的关系,并分析影响文化资源分布的原因,得出以下结论：① 格萨尔文化资源可以分为4大类,11个亚类和60个子类,果洛的格萨尔文化资源覆盖全部类型,共1189个;② 果洛格萨尔文化资源空间分布具有聚集性,其中A类文化人（团体）类集聚程度最高,并通过最近邻分析和密度分析对各类文化资源的集聚空间进行识别;③ 格萨尔文化资源的空间分布与自然地理条件有关,多位于海拔相对较低、距水源地较近的位置,不同类型的文化资源分布对坡度、坡向和可达性的关系不同。  相似文献   

Analysis of the Spatio-temporal Changes in Acid Rain and Their Causes in China (1998-2018)     

CHEN Xuan  SHAN Xiaoran  SHI Zhaoji  ZHANG Jiaen  QIN Zhong  XIANG Huimin  WEI Hui 《资源与生态学报(英文版)》2021,12(5):593-599

With the rapid development of the economy, acid rain has become one of the major environmental problems that endanger human health. Being the largest developing country, the environmental problems caused by acid rain are of increasing concern with the rapid industrialization and urbanization in China. Recently, many researchers have focused on acid rain. To better understand the temporal and spatial dynamics of acid rain in China, the monitoring data on acid rain from 1998 to 2018 were studied using ArcGIS 10.2. The results show that the proportion of acid rain cities, the frequency, and the area of acid rain were decreasing, however, the situation still remains serious. Overall, the chemical type of acid rain was mainly sulfuric acid rain. However, the concentration ratio of SO₄ ^2-/NO₃ ^- decreased by 81.90% in 2018 compared with 1998, and presented a decreasing trend, which indicates that the contribution of nitrate to precipitation acidity has been increasing year by year. This research will help us to understand the distribution characteristics and causes of acid rain in China, and it may provide an effective reference for the prevention and control of acid rain in China.  相似文献   

Effects of Enclosure on Plant and Soil Restoration in the Junggar Desert     

WEI Peng  AN Shazhou  KE Mei  LI Chao  HOU Yurong  LAN Jiyong  KANG Shuai  JIN Junpeng 《资源与生态学报(英文版)》2021,12(6):840-848

Enclosure is commonly used in the restoration of degraded grasslands. However, the effects of enclosure on grassland plant and soil restoration remain controversial, particularly in deserts. To assess the effects of enclosure on desert plants and soil properties, using high throughput sequencing, the differences between plants and soil were systematically analyzed before and after enclosure construction. The soil organic carbon, total nitrogen and total phosphorus contents of the three desert flora increased and decreased, but the difference was not significant; enclosure increased plant height, coverage, aboveground biomass, and species richness by 58.99%, 59.35%, 33.29%, and 51.21%, respectively, in a Seriphidium transiliense formation; by 15.49%, 33.52%, 20.85%, and 5.13%, respectively, in a Haloxylon persicum formation; and by 83.80%, 31.51%, 76.66% and 33.33%, respectively, in an Anabasis salsa formation. For soil bacteria, enclosure significantly increased the average number of operational taxonomic units and Shannon-Wiener index by 12.74% and 2.92%, respectively, under S. transiliense formation and by 17.08% and 3.17%, respectively, under H. persicum formation. However, enclosure had no significant effect on the average number of operational taxonomic units or Shannon-Wiener index under A. salsa formation. Enclosure significantly increased desert plants, soil bacterial diversity, and desert plant community productivity; however, the increase in soil nutrient content was not significant. These results demonstrate that enclosure is effective for restoring desert ecosystems but may have little effect on the soil nutrient content.  相似文献   

Statistics-based Optimization of the Polarimetric Radar Hydrometeor Classification Algorithm and Its Application for a Squall Line in South China     

Chong WU  Liping LIU  Ming WEI  Baozhu XI  Minghui YU 《大气科学进展》2018,35(3):296-316

A modified hydrometeor classification algorithm(HCA) is developed in this study for Chinese polarimetric radars. This algorithm is based on the U.S. operational HCA. Meanwhile, the methodology of statistics-based optimization is proposed including calibration checking, datasets selection, membership functions modification, computation thresholds modification,and effect verification. Zhuhai radar, the first operational polarimetric radar in South China, applies these procedures. The systematic bias of calibration is corrected, the reliability of radar measurements deteriorates when the signal-to-noise ratio is low, and correlation coefficient within the melting layer is usually lower than that of the U.S. WSR-88D radar. Through modification based on statistical analysis of polarimetric variables, the localized HCA especially for Zhuhai is obtained,and it performs well over a one-month test through comparison with sounding and surface observations. The algorithm is then utilized for analysis of a squall line process on 11 May 2014 and is found to provide reasonable details with respect to horizontal and vertical structures, and the HCA results—especially in the mixed rain–hail region—can reflect the life cycle of the squall line. In addition, the kinematic and microphysical processes of cloud evolution and the differences between radardetected hail and surface observations are also analyzed. The results of this study provide evidence for the improvement of this HCA developed specifically for China.  相似文献   

定量测量降水量的回波结构自适应算法研究          下载免费PDF全文

魏鸣  宋羽轩  张蕾 《大气科学学报》2018,41(5):676-683

为提高临近预报中对流性降水估测的准确性,分析了统计法估算降水的局限性。依据降水物理机制和降水回波结构,研究雷达反射率因子定量测量降水量(QPE-Qualitative Precipitation Estimate)的自适应算法,旨在减少由于雨滴谱变化导致的Z-I关系不稳定所引起的降水量测量误差。同时考虑组合反射率因子RC和垂直液态水含量VIL两个参量对降水的影响,建立适于城市区域的动态自适应的Z-I关系,改进对强降水严重低估的问题。  相似文献   

An Abrupt Rainfall Decrease over the Asian Inland Plateau Region around 1999 and the Possible Underlying Mechanism     

Jinling PIAO  Wen CHEN  Ke WEI  Yong LIU  Hans-F. GRAF  Joong-Bae AHN  Alexander POGORELTSEV 《大气科学进展》2017,34(4):456-468

A decadal change in summer rainfall in the Asian inland plateau(AIP) region is identified around 1999. This decadal change is characterized by an abrupt decrease in summer rainfall of about 15.7% of the climatological average amount,leading to prolonged drought in the Asian inland plateau region. Both the surface air temperature and potential evapotranspiration in the AIP show a significant increase, while the soil moisture exhibits a decrease, after the late 1990s. Furthermore,the normalized difference vegetation index shows an apparent decreasing trend during 1999–2007. Three different drought indices—the standardized precipitation index, the standardized precipitation evapotranspiration index, and the self-calibrating Palmer drought severity index—present pronounced climate anomalies during 1999–2007, indicating dramatic drought exacerbation in the region after the late 1990s. This decadal change in the summer rainfall may be attributable to a wave-like teleconnection pattern from Western Europe to Asia. A set of model sensitivity experiments suggests that the summer warming sea surface temperature in the North Atlantic could induce this teleconnection pattern over Eurasia, resulting in recent drought in the AIP region.  相似文献   

基于动态聚类法的安顺降雪环流分型研究          下载免费PDF全文

韦琦  吴哲红  王兴菊  曾妮  蒙军 《中低纬山地气象》2022,46(3):74-79

该文以500 hPa环流作为关键影响因子,采用K-means动态聚类分型,将近10 a安顺降雪划分为平直气流型（Ⅰ）、南支槽型（Ⅱ）、多波动型（Ⅲ）3种主要形势。个例分析和合成分析表明:3种形势下降雪过程中相态变化、区域、持续时间等特点有所不同。合成分析还表明：3种形势在500 hPa环流上有明显的区别,Ⅰ型在高原东侧到贵州的气流基本平直,Ⅱ型从高原东侧到贵州有1个明显的南支槽,Ⅲ型在高原东侧到贵州有多个波动槽影响,在高原北侧沿河套地区和孟湾以东均有槽影响,形成阶梯槽。此外滇黔准静止锋的强度、影响区域、物理量以及垂直方向湿度配置、逆温等方面均有所区别：Ⅰ型湿层和上升区浅薄,有1℃左右逆温;Ⅱ型湿层较薄,Ⅱ型在贵州中部有3℃逆温范围较窄;Ⅲ型中低层有宽广的湿层,水汽和抬升条件配合较好,几乎没有逆温。  相似文献   

南秦岭胭脂坝花岗岩成因:锆石U-Pb年龄、地球化学和Sr-Nd-Pb同位素的制约   总被引：1，自引：0，他引：1  

韦龙猛  杨一增  张贺  贺剑峰  陈福坤 《地球科学与环境学报》2016,(4):527-546

秦岭造山带广泛发育新元古代、古生代、早中生代和晚中生代岩浆作用,是长期复杂造山作用的结果。胭脂坝花岗岩岩体出露于南秦岭宁陕地区五龙岩体群的最东部,是南秦岭早中生代花岗岩的重要组成部分。5个花岗岩样品的锆石U-Pb定年结果分别为(202.9±3.5)、(201.0±3.0)、(202.1±2.6)、(200.4±5.4)、(~(205).5±3.3)Ma,平均年龄为(201.9±1.5)Ma,属于早中生代五龙岩体群岩浆作用中晚期的产物。岩石地球化学成分显示该岩体的主体为黑云母花岗岩,具有高硅、富碱的地球化学特征,富集大离子亲石元素,亏损高场强元素,属于弱过铝质、高钾钙碱性岩石系列。初始Sr同位素组成为0.704 31~0.706 78,ε_(Nd)_(t)值为-5.2~-2.0,初始Pb同位素组成相对高,(N(~(206) Pb)/N(~(204) Pb))_(t)=17.737~18.191,(N(~(207) Pb)/N(~(204) Pb))_(t)=15.511~15.574,(N(~(208)Pb)/N(~(204)Pb))_(t)=37.439~38.071。较高的放射性成因Pb同位素组成说明胭脂坝岩浆源区具有扬子地块的属性;初始Sr同位素组成和ε_(Nd)_(t)值随着SiO2含量的升高呈现出线性变化趋势,说明胭脂坝花岗质岩浆在上升侵位过程中存在围岩物质的同化作用;结合与新元古代火山沉积岩(如耀岭河群、武当群、碧口群)相似的初始Sr-Nd同位素组成,推测胭脂坝岩体的岩浆源区主要是具有扬子地块属性的新元古代地壳物质。  相似文献   

多因素耦合下三峡库区土地利用未来情景模拟   总被引：21，自引：3，他引：18  

邓华  邵景安  王金亮  高明  魏朝富 《地理学报》2016,71(11):1979-1997

模型模拟和情景变化分析是未来土地利用变化研究的核心内容,本文以2000年三峡库区土地利用现状为基期数据,利用Binary Logistic模型回归分析驱动因子与土地利用间的关系,利用CLUE-S模型对2010年土地利用进行模拟,校验并确定影响库区土地利用驱动因素的主要参数后,基于自然增长、粮食安全、移民建设和生态保护对2020年、2030年库区土地利用情景予以模拟。结果表明：① 通过Binary Logistic模型分析和检验,水田、旱地、林地、草地、建设用地和水域的ROC曲线下面积值均大于0.8,表明所选驱动因子对土地利用的解释能力较强,可用来估算土地利用概率分布;② 2010年各地类模拟结果经验证得Kappa系数分别为水田0.9、旱地0.92、林地0.97、草地0.84、建设用地0.85和水域0.77,总体上能满足模拟与预测需求;③ 多情景模拟显示库区不同土地利用类型在空间上的竞争关系,以及所带来的对库区粮食安全、移民建设、生态保护的影响,包括水田大量转换为旱地（“水改旱”）、耕地与林草地被建设占用、林草地开垦为耕地、陡坡耕地退为林草地等行为,需要在土地利用优化中平衡各方面的需求;④ 多因素、多情景模拟能为库区土地利用提供更为清晰的、可供抉择的政策调控思路。  相似文献