The temporal-spatial variation of water resources constraint on urbanization in the northwestern China: examples from the Gansu section of west Longhai–Lanxin economic zone     

Xiang Gao  Tengfei Yu 《Environmental Earth Sciences》2014,71(9):4029-4037

Based on more than 2,000 data points reflecting various meaningful aspects of urban systems and water-resource systems, and using a quantitative measurement model and ArcGIS, this study discusses the temporal-spatial variations of water resources constraint on urbanization in the Gansu section of China. The conclusions were: (1) from 1989 to 2007 the water resources constraint intensities (WRCIs) of Gansu section and its 9 cities have been generally decreasing, albeit with much fluctuation, and the decrease has been more rapid since 2000, with Lanzhou and Jinchang as the most representative cities. There is, however, a great deal of variation of WRCI among the 9 cities: Lanzhou changed from intensive constraint to relatively strong constraint, with a significant decline in its WRCI; 5 cities changed from extreme constraint to intensive constraint, including Wuwei and Jiuquan with significant declines in their WRCI, Jiayuguan and Jinchang with no dramatic declines and Dingxi with a fluctuating decline; and 3 cities remained at the same level of water resources constraint, including Zhangye and Baiyin with extreme constraint, and Tianshui with intensive constraint. (2) Looking at the 20-year average of WRCI, there are three types of spatial variations among the 9 cities in the Gansu section: Lanzhou, the capital city of Gansu Province, belongs to the relatively strong constraint-high type; 4 cities—Jiuquan, Jiayuguan, Jinchang and Tianshui—belong to the intensive constraint-high type; and the remaining 4 cities—Zhangye, Wuwei, Baiyin and Dxingxi—belong to the extreme constraint-low type. These results show that the Gansu section will continue to be affected by water resources constraint on urbanization and local economic development for some time to come.  相似文献   

云南两次中尺度对流雷暴系统演变和地闪特征   总被引：3，自引：2，他引：1       下载免费PDF全文

张腾飞  尹丽云  张杰  谢屹然  朱莉 《应用气象学报》2013,24(2):207-218

在利用NCEP/NCAR再分析资料诊断分析2010年9月21—23日中尺度对流雷暴系统形成的环流背景基础上,通过云南省闪电定位系统地闪监测资料和FY-2E卫星云图资料的同步叠加, 分析两个中尺度雷暴系统的演变和地闪特征。结果表明:台风凡亚比 (1011) 西行减弱的热带低压为中尺度对流雷暴系统提供有利的暖湿和抬升动力环流背景,促使中尺度弧状对流云带、中尺度雷暴云团和中尺度对流复合体生成和发展。雷暴云团结构和地闪活动空间分布不均匀并随时间变化,且正、负地闪频数与云顶亮温 (TBB) 相关,当TBB降低和等值线密度变大,雷暴云团发展,低TBB中心偏于云团的前部云区,负地闪频数剧增;当TBB达最低值时,雷暴云团成熟,负地闪频数达峰值,正地闪出现;当TBB升高且等值线密度变小时,雷暴云团减弱,低TBB中心靠近云团中心,负地闪频数迅速减小,正地闪频数达到峰值;密集的负地闪出现在雷暴云团前部大的TBB梯度区和TBB不大于-56℃的低值中心附近,正地闪分散在TBB不大于-56℃的低值中心附近,偏于负地闪区域后部发生。  相似文献   

利用日晕光度计反演大气水汽含量     

宋腾飞  刘顺庆  张雪飞 《气象科技》2013,41(1):46-50

大气总水汽含量是天文观测和气象科学领域最为重要的参量之一.介绍云南天文台研制的新一代日晕光度计反演大气水汽含量的原理和方法,分析了新一代日晕光度计在天文选址和气象科学中的应用,给出了其在丽江高美古地区测试的结果,并和其他仪器测试结果进行了对比分析.结果表明:新一代日晕光度计反演大气水汽含量方法直观,性能稳定,能很好地应用于云南天文台的西部太阳望远镜选址及气象科学研究工作.  相似文献   

遥感结合地面观测估算陆地生态系统蒸散发研究综述   总被引：2，自引：1，他引：1  

鱼腾飞  冯起  司建华  席海洋  陈丽娟 《地球科学进展》2011,26(12):1260-1268

地面观测和遥感模拟作为陆地生态系统蒸散发研究的2种基本手段,有着各自的优缺点且存在互补性。因此,有效地将遥感和地面观测站点资料相结合,探讨陆地生态系统蒸散发的时空分布规律及不同尺度转换理论与方法,实现蒸散耗水地面观测结果的尺度扩展和生态需水量估算成为普遍关注的焦点。从遥感与地面观测结合确定陆地生态系统蒸散发入手,论述目...  相似文献   

C波段双偏振天气雷达降雨和部分地形遮挡衰减订正研究     

夏丰  刘显通  郑腾飞  冯璐  万齐林  欧冠华  张晓飞 《热带气象学报》2021,37(4):556-568

天气雷达可为中尺度对流系统研究提供高时空分辨率资料, 但降雨衰减和地形遮挡等因子会对雷达信号产生严重影响。针对广东省韶关市新丰县C波段双偏振天气雷达, 选取了2018年6月8日台风“艾云尼”、8月30日华南季风降水和9月16日台风“山竹”三次降雨过程, 采用基于差分相位(Φ_DP)数据的扩展自适应降雨廓线算法对雷达反射率因子(Z_H)数据进行了降雨衰减和部分地形遮挡衰减订正研究, 并将订正结果与广州S波段双偏振天气雷达探测结果进行了直接对比检验, 与中国气象局龙门云物理野外科学试验基地的4台二维视频雨滴谱仪(2D Video Distrometer, 2DVD)实测雨滴谱数据反演的雷达仿真探测量及国内外Z_H-K_DP经验统计公式进行了间接对比检验, 获得较好结果。最后选择具体降雨个例, 订正结果清晰展现了台风螺旋雨带中对流单体雷达回波强度从地面到高空的垂直结构特征, 提高了复杂地形区域雷达对极端天气的近地面探测能力。   相似文献   

基于SQL的坝体监测系统数据运算优化   总被引：1，自引：0，他引：1  

杨阳  包腾飞 《武汉大学学报(信息科学版)》2011,(2):244-247

为适应大坝监测系统中对大量数据进行快速复杂计算的要求,利用SQL语言对数据集灵活操作的优势,提出了一种基于SQL数据计算的运算结构,通过对SQL软件的二次开发,并结合大坝监测系统中统计计算建模的特点,将原本软件对数据的运算操作转化为SQL的直接运算,最终达到数据计算集成的一体化。系统运行结果显示,新方法的应用提高了系统的运算速度和软件的操作性能,简化了系统算法的编写,达到了系统的优化开发。  相似文献   

胡杨(Populus euphratica)树干液流特征及其与环境因子的关系     

赵春彦  司建华  冯起  鱼腾飞  李炜 《中国沙漠》2014,34(3):718-724

以2012年4—10月实测数据,对黑河下游胡杨树干液流特征及其与环境因子的关系进行了分析。结果表明:在整个生长季,胡杨(Populus euphratica)树干液流速率日变化具有明显的昼夜节律性,夜间存在明显的树干液流以补充白天蒸腾损失的大量水分,恢复植物体内的水分平衡;与其他天气条件下树干液流速率特征比较,阴雨天液流启动时间推迟,液流停止时间提前,液流历时缩短,且峰值显著缩小;树干液流的季节变化特征表现为液流速率在夏季的启动时间、到达峰值的时间、液流停止时间均早于春季和秋季;单株蒸腾耗水表现出明显的季节性格局,4月和10月中下旬耗水量较低,5—8月为主要耗水期,占整个生长季的75%;日间液流速率主要受到土壤含水量、水汽压差、光合有效辐射、相对湿度和气温的影响,夜间液流速率主要受到水汽压差、相对湿度的影响,整个生长季胡杨树干液流主要受光合有效辐射、土壤水分、气温和相对湿度的影响。  相似文献   

Variability of the deep South China Sea circulation derived from HYCOM reanalysis data     

Yaohua Zhu  Guojiao Cao  Yonggang Wang  Shujiang Li  Tengfei Xu  Dingqi Wang  Fei Teng  Zexun Wei 《海洋学报(英文版)》2022,41(7):54-64

This study aims to investigate variability of the deep South China Sea (SCS) circulation using the Hybrid Coordinate Ocean Model (HYCOM) global reanalysis product. The results reveal that annual cycle is a dominant component in the deep SCS circulation. Meanwhile, the boundary circulation strength is the weakest in January and peaks between June and September. The eastern and southern boundary currents strengthen/weaken one to three months earlier than that in the western and northern boundaries. Vector Empirical Orthogonal Functions (VEOF) analysis results reveal that semiannual and intraseasonal fluctuations are significant components, of which the spatial patterns are mainly confined in the northern and western boundary areas as well as the southwestern sub-basin. Wavelet analysis results show the strength of significant fluctuation varies year to year. Trend analysis results indicate a decadal weakening in the deep SCS circulation. An anomalous anticyclonic circulation, 50–70 km apart from the slope break, tends to weaken the cyclonic boundary circulation in the western and northern boundaries as well as the southwestern sub-basin. This trend is similar to the observed decadal weakening in the North Atlantic deep circulation. Thus, the findings of this study reveal that the variation of the deep SCS circulation has a remarkable response to the climate change. The mechanisms responsible for the variation are worth pursuing if more observations are available.  相似文献   

Vertical velocity and transport in the South China Sea     

Yaohua Zhu  Dingqi Wang  Yonggang Wang  Shujiang Li  Tengfei Xu  Zexun Wei 《海洋学报(英文版)》2022,41(7):13-25

Deep water in the South China Sea is renewed by the cold and dense Luzon Strait overflow. However, from where and how the deep water upwells is poorly understood yet. Based on the Hybrid Coordinate Ocean Model reanalysis data, vertical velocity is derived to answer these questions. Domain-integrated vertical velocity is of two maxima, one in the shallow water and the other at depth, and separated by a layer of minimum at the bottom of the thermocline. Further analysis shows that this two-segmented vertical transport is attributed to the vertical compensation of subsurface water to the excessive outflow of shallow water and upward push of the dense Luzon Strait overflow, respectively. In the abyssal basin, the vertical transport increases upward from zero at the depth of 3 500–4 000 m and reaches a maximum of 1.5×106 m3/s at about 1 500 m. Deep water upwells mainly from the northeastern and southwestern ends of the abyssal basin and off the continental slopes. To explain the upward velocity arising from slope breaks, a possible mechanism is proposed that an onshore velocity component can be derived from the deep western boundary current above steep slopes under bottom friction.  相似文献   

三沙永乐蓝洞成因机制初探*     

高金尉  付腾飞  赵明辉  张汉羽  田丽艳 《热带海洋学报》2022,41(1):171-183

海洋蓝洞保留了原始的水体、沉积物、化石残骸和完整的生物骨骼, 是重要的自然遗产和地质奇观, 具有重要的科学研究价值。三沙永乐蓝洞是目前全球已发现的最深海洋蓝洞, 有着独特的洞体结构和水体化学特征, 但其成因仍是未解之谜。本文结合南海的构造演化, 分析了永乐环礁碳酸盐岩台地的发育历史, 认为永乐环礁的形成以加积和退积为主, 其台地边缘属于陡崖型台地斜坡, 有利于发育断层/裂缝; 永乐环礁之上钻井岩心的氧同位素数据表明, 永乐环礁在14.75~168.60m的深度范围内发生了地下水溶蚀作用, 这与实际观测到的158m深洞体转折处之上发生的洞穴垮塌作用相符。通过综合对比分析认为, 三沙永乐蓝洞的形成是断层/裂缝溶蚀机制与深部洞穴垮塌机制综合作用的结果。地下水(淡水、海水)首先沿着台地边缘发育的断层/裂缝进行溶蚀, 在158m以上通过洞穴垮塌作用形成了近垂直的洞穴, 而在158m以下则沿着断层/裂缝继续向下溶蚀形成了略倾斜的深部洞穴结构, 最终由于海平面的上升淹没而形成了蓝洞。本研究可为未来寻找更多海洋蓝洞提供重要的经验与借鉴。  相似文献