植物功能性状对城市湿地水体富营养化的响应研究进展     

肖涛  宋垚彬  姜丹  李文兵  董鸣 《湿地科学与管理》2014,(2):62-65

城市湿地是构成城市复合生态系统重要的生态系统类型,在维持城市生态系统安全方面具有不可替代的作用。城市湿地面临的主要问题之一是水体富营养化,主要是由于人类活动引起的氮、磷元素的过量输入和N∶P比例失调所导致的一系列生态问题。从植物全株性状、叶片性状、茎和根性状以及繁殖性状等方面综述了湿地高等植物功能性状对湿地水体富营养化的响应,并展望了今后可能的研究方向。  相似文献   

专家解读:不动产登记是一种“倒逼”力量     

王立彬 《西部资源》2014,(4):55-55

<正>国务院常务会议讨论《登记暂行条例(征求意见稿)》,强调建立不动产统一登记制度是推进简政放权,整合部门职能职责,方便企业和群众的有效举措,并决定将征求意见稿向社会公开征求意见,之后再推进相关法律修改工作。近日召开的国务院常务会议讨论《登记暂行条例(征求意见稿)》,强调建立不动产统一登记制度是推进简政放权,整合部门职能职责,方便企业和群众的有效举措,并决定将征求意见稿向  相似文献   

临潭 秦岭淮河零度等温线上的靓丽城市     

谭敏章 《中国地名》2014,(3):68-69

临潭,古称洮州,地处中国内陆青藏高原东北边缘,甘肃省南部,甘南藏族自治州东部。东邻岷县,北接康乐、渭源两县,与卓尼县插花接壤。临潭县地形西高东低,大多地区属高山丘陵地带,  相似文献   

西安秦岭淮河零度等温线上享有“天然历史博物馆”盛誉的美丽城市     

安萍 《中国地名》2014,(5):67-68

西安,是举世闻名的世界四大文明古都之一,居中国古都之首,是影响力最大的都城,是中华民族的摇篮、中华文明的发祥地、中华文化的代表。历史上,西安曾经是中国的政治、经济、文化中心和最早对外开放的城市,是著名的丝绸之路的起点。西安以中国历史上建都时间最长、建都朝代最多的城市,素有“秦中自古帝王州”的美称、以秦始皇陵兵马俑的出土而享有“世界第八大奇迹”诞生地之美誉、以历史文化悠久享有“天然历史博物馆”之盛誉。  相似文献   

荷兰首都阿姆斯特丹 人居水上水入城中人水相依的景观城市     

黄建华 《中国地名》2014,(6):80-80

水全市有160多条大小水道桥全市有1000余座桥船全市河面上有近2万家“船屋”荷兰首都阿姆斯特丹位于艾瑟尔湖西南岸,人口79万（2012年）。阿姆斯特尔河从市内流过,从而使该城成为欧洲内陆水运的交汇点。阿姆斯特丹是一座奇特的城市。全市共有160多条大小水道,由1000余座桥梁相连。漫游城中,桥梁交错,河渠纵横。从空中鸟瞰,波光如缎,状似蛛网。市内地势低于海平面1—5米,被称为“北方威尼斯”。由于地少人多,河面上泊有近2万家“船屋”。过去,城市的建筑几乎均以涂了黑柏油的木桩打基,  相似文献   

有巴蜀之雄浑刚强 有荆楚之柔媚清丽 有三秦之古朴粗犷 安康 蕴有“万年丰乐 安宁康泰”之意的美丽城市     

张占国 《中国地名》2014,(8):46-46

安康市位于陕西省东南部,居川、陕、鄂、渝交接部,南依巴山北坡,北靠秦岭主脊,东与湖北省的郧县、郧西县接壤,东南与湖北省的竹溪县、竹山县毗邻,南接重庆市的巫溪县,西南与重庆市的城口县、四川省的万源市相接,西与汉中市的镇巴县、西乡县、洋县相连,西北与汉中市的佛坪县、西安市的周至县为邻,北与西安市的户县、长安区接壤,东北与商洛市的柞水县、镇安县毗连。安康市在石器时代已有人类活动。  相似文献   

太原城市下垫面扩张对边界层特征影响的个例研究   总被引：1，自引：0，他引：1  

董春卿  郭媛媛  赵桂香  邱贵强 《干旱气象》2014,32(6):916-925

通过高分辨率卫星夜间灯光数据获取最新的城市地表分布,并利用高分辨率数值模式对2013年8月14~16日太原区域的一次高温过程进行研究,探讨城市下垫面扩张对大气边界层的影响。结果表明：基于DMSP/OLS夜间灯光数据对模式中地表参数修正后,能够更准确地反映太原主城区和高速公路沿线小规模建筑群的扩张,有效改善了模式的预报性能,显著提高对近地面气温、地表温度的预报能力。城市下垫面的扩张,使城区夜间升温明显,热岛强度增强。与1992年的城市化状况相比,晴空天气条件下,2012年太原城区夜间气温上升5℃,热岛强度升高2~3℃。城市下垫面扩张,改变了地表能量分配关系,使得地表感热传输明显加强,潜热通量明显减弱,城市冠层作用下的储热能力增强。边界层内部湍流交换、水汽输送等的进一步研究表明：城市地表水汽输送减弱,边界层水汽含量减少,2~4 km高度的水汽含量增加,湍流动能的影响高度增高,湍流混合加剧;14：00,城区边界层高度抬高了800 m,城市上空混合层加深,持续时间更长。  相似文献   

Urban Economic Cluster Template and Its Dynamics of Beijing,China     

YANG Zhenshan  LIANG Jinshe  CAI Jianming 《中国地理科学(英文版)》2014,(6):740-750

Economic clusters have been a central focus of current urban and regional research, policies and practices. However, a meth- odology to identify and analyze policy-relevant economic cluster dynamics is still not well developed. Based on input-output （I-O） data of 1987, 1992, 1997, 2002 and 2007 of Beijing, this article presents an adapted principle component analysis for identifying the evolu- tion of local economic cluster patterns. This research addresses the changes of economic interaction of industries with complementary and common activities over time. The identified clusters provide an insight into the reality of economic development in a diversifying urban economy： the increasing importance of services and the growing interaction between service and manufacturing industries. Our method therefore provides the analysts with a better understanding of the emergence, disappearance and development of economic clus- ters citywide. The results could be used to assist monitoring urban economic development and designing more practical urban economic strategies.  相似文献   

Spatial structure of central places in Jilin Central Urban Agglomeration,Jilin Province,China   总被引：1，自引：1，他引：0  

Shijun Wang  Yongchao Wang  Dan Wang 《中国地理科学(英文版)》2014,24(3):375-383

Using the radius of gyration from fractal theory, this paper describes the calculation of fractal dimensions for the four tiers of central places in the Jilin Central Urban Agglomeration(JCUA), Jilin Province, China and the structural characteristics of each tier: 1) the 1st tier central place, Changchun Proper(not including Shuangyang District), provides the most service functions and has the most stable primate position; 2) the 2nd tier central places, Jilin Proper, Siping Proper, Liaoyuan Proper and Songyuan Proper have unclear statuses and do not provide certain functions; 3) the 3rd tier central places comprise 23 county-level cities, counties and urban districts(including Shuangyang District of Changchun), exhibiting a dense spatial structure that agrees with theory; 4) the 4th tier contains the largest number of central places(248 designated towns), but they are loosely distributed. In this study, a spatial image of the JCUA was created, based on vectorized data of the urban settlement distribution, which was then modified and abstracted to create a hexagonal network covering the JCUA. Compared to the traditional central place model, the modified spatial image conforms to the K = 3 principle. In reality, however, the growth of some 3rd tier central places should be increased with the cities being upgraded to the 2nd tier so as to overcome that tier′s functional deficiency. The loose distribution in the 4th tier should also be changed. This apparent anomaly can be explained by the fact that the classic hexagon model used to describe the way market areas layout does not exist in the real world. However, this should not be viewed as an obstacle to using central place theory. If its assumptions are properly applied, it can still assist research into the spatial structure of regions.  相似文献   

Empirical Analysis of City Contact in Zhujiang （Pearl） River Delta,China     

TONG De  LIU Tao  LI Guicai  YU Lei 《中国地理科学(英文版)》2014,24(3):384-392

In traditional urban geography, city contact research is a classic study element in city research. In general, researchers use the traditional gravity model to characterize the contacts that exist between two cities. The traditional gravity model assumes ideal condi- tions, but these preconditions and their results often do not exist in realistic conditions. Thus, we used a modified gravity model to char- acterize the city contacts within a specific region. This model considers factors such as intercity complementarities, government inter- vention, and the diversity of the transportation infrastructure which is characterized as the transportation distance instead of the tradi- tional Euclidean distance. We applied this model to an empirical study of city contact in the Zhujiang （Pearl） River Delta （PRD） of China. The regression results indicated that the modified gravity model could measure city contact more accurately and comprehen- sively than the traditional gravity model, i.e., it yielded a higher adjusted R2 value （0.379） than the traditional gravity model result （0.259）. Our study also suggests that, in addition to urban-regional and metropolitan development, the complementarities of the basic functions of cities at the administrative and market levels, as well as the corporeal and immaterial levels, play very significant roles in the characterization of city contact. Given the complexity of city contact, it will be necessary to consider more relevant influential fac- tors in the modified gravity model to characterize the features of city contact in the future.  相似文献