一次台风外围特大暴雨的结构特征   总被引：3，自引：0，他引：3  

李云川  张杏敏  周须文 《气象》1999,25(7):21-24

分析了１９９６年８月３￣５日河北省西南部致洪暴雨最大时段的卫星云图、雷达回波、地面风场及θｓｅ场的分布特征。结果发现,中－α尺度云团中的中－β和中－γ尺度云团不仅可使降水增幅,而且可以直接引起强降水产生;另外湿中性结构有利于特大暴雨的产生和加强。  相似文献   

美国内华达卡林成矿带的金矿地质特征   总被引：2，自引：0，他引：2  

赵省民  聂凤军  江思宏 《内蒙古地质》2000,(2)

卡林成矿带是北美规模最大的金矿富集带。本文旨在通过对此成矿带地质背景、岩石特征、构造特征与成矿特征的详尽研究 ,分析成矿作用机理 ,确定有利成矿控制因素 ,为在地质环境类似地区寻找金矿床提供理论依据。  相似文献   

WT模型在山区高速公路风预报订正中的应用     

曲晓黎  张杏敏  尤琦  张中杰  吴丹 《气象科技》2022,50(2):267-272

利用2001—2020年河北省142个国家气象站逐日最大风速资料分析了近20年河北风速变化背景。择选2021年2—5月张家口、崇礼区域日极大风速13.9 m/s以上、日10 min平均风速最大值8 m/s以上的30个代表日,运用张承高速公路沿线崇礼国家气象站、南窝铺及场地2套区域气象站、高家营及西湾子2套交通气象站的逐分钟风向风速观测资料,ECMWF数值模式输出的地面10 m风预报资料,以及3″分辨率的SRTM3地形资料,应用Meteodyn WT模型对张承高速公路沿线2个解域区域内的风预报结果进行了订正和检验。结果表明：WT模型输出风速与实际观测风速相关系数可达0.6225并通过0.001显著性检验,各代表站模拟的结果与实况的误差80%以上在±2 m/s之间,地形开阔处误差明显减小;风向也表现出很高的一致性。说明应用WT模型对山区高速公路沿线风数值预报进行订正是可行的,各地可结合本地地形数据以及相对稳定可靠的风的数值预报产品作为WT模型的驱动数据源,开展本地山区高速公路沿线风的订正应用。  相似文献   

Run-off affected by climate and anthropogenic changes in a large semi-arid river basin     

Xiaonan Yang  Wenyi Sun  Xingmin Mu  Peng Gao  Guangju Zhao 《水文研究》2020,34(8):1906-1919

A rapid reduction in run-off has been observed in the middle reaches of the Yellow River basin in recent decades. Understanding the contributions of climate change and human activities, such as vegetation restoration and water consumption, to surface water resource reduction has become urgent and very important for future regional planning. Here, we use attribution approaches to explore the effects of climate change and human activities on run-off over the past six decades. The results showed that the observed annual run-off at Tongguan station, which is located within the mainstream of the Yellow River, exhibited a significant decreasing trend of −0.69 mm year⁻¹ (p < .01) and varied from −0.28 to −1.46 mm year⁻¹ (p < .01) in the eight selected tributaries from 1960 to 2015. Two relatively abrupt changes in the double mass curves occurred around 1979 and 1999; compared with Period 1 (P1; 1960–1979), the average catchment run-off decreased 32% during Period 2 (P2; 1980–1999) and up to 49% during Period 3 (P3; 2000–2015). We calculated that approximately 29% of the reduction in the run-off during P2 and 18% during P3 were attributed to climate change. Increased surface water consumption resulted in effective run-off reduction, with relative contributions of approximately 27% and 28% during P2 and P3, respectively. With the implementation of the “Grain-for-Green” project, the vegetation coverage rapidly increased from 36% in P1 to 52% in P3 and reduced run-off by 35% during P3. These findings explain the run-off reduction and benefit water resource management in the middle reaches of the Yellow River basin.  相似文献   

基于地质灾害的陇南山区生态风险评价——以陇南市武都区为例     

巩杰  赵彩霞  王合领  孙朋  谢余初  孟兴民 《山地学报》2012,(5):570-577

陇南山区地质构造活动强烈,频繁的地质灾害对生态环境和生态安全构成严重威胁。分别以陇南市武都区的主要地质灾害(滑坡、泥石流和地震)和景观类型为风险源和受体,以景观结构指数和易损性指数作为评价指标,构建生态风险评价模型,进行生态风险特征评估。结果表明:武都区生态风险特征的分布主要受地质灾害风险分布和景观格局的影响,人类活动、植被覆盖度和海拔梯度也是重要的影响因素。极高风险区和高风险区主要集中分布在东江镇以东的白龙江沿岸及整个白龙江南岸、安化、马街、汉王和两水镇北部等地;低风险区和较低风险区主要分布在武都区东部和南部以及西部和西北部区域。基于景观结构的多风险源生态风险评价对于区域生态风险管理具有重要的现实和指导意义。  相似文献   

Variations in runoff,sediment load,and their relationship for a major sediment source area of the Jialing River basin,southern China     

Yiting Shao  Xingmin Mu  Yi He  Kai Chen 《水文研究》2021,35(7):e14297

Investigation of the variations in runoff, sediment load, and their dynamic relation is conducive to understanding hydrological regime changes and supporting channel regulation and fluvial management. This study is undertaken in the Xihanshui catchment, which is known for its high sediment-laden in the Jialing River of the Yangtze River basin, southern China, to evaluate the change characteristics of runoff, sediment load, and their relationship at multi-temporal scales from 1966 to 2016. The results showed that runoff changed significantly for more months, whereas the significant changes in monthly sediment load occurred from April to September. The contributions of runoff in summer and autumn and sediment load in summer to their annual value changes were greater. Annual runoff and sediment load in the Xihanshui catchment both exhibited significant decreasing trends (p < 0.05) with a significant mutation in 1993 (p < 0.05). The average annual runoff in the change period (1994–2016) decreased by 49.58% and annual sediment load displayed a substantial decline with a reduction of 77.77% in comparison with the reference period (1966–1993) due to climate change and intensive human activity. The power functions were satisfactory to describe annual and extreme monthly runoff–sediment relationships, whereas the monthly runoff–sediment relationship and extreme monthly sediment-runoff relationship were changeable. Spatially, annual runoff–sediment relationship alteration could be partly attributed to sediment load changes in the upstream area and runoff variations in the downstream region. Three quantitative methods revealed that the main driver for significant reductions of annual runoff and sediment load is the human activity dominated by soil and water conservation measures, while climate change only contributed 22.73%–38.99% (mean 32.07%) to the total runoff reduction and 3.39%–35.56% (mean 17.32%) to the total decrease in sediment load.  相似文献   

1919—2010年黄河上中游区径流量变化分析   总被引：5，自引：0，他引：5       下载免费PDF全文

李二辉  穆兴民  赵广举 《水科学进展》2014,25(2):155-163

应用Mann-Kendall秩次相关检验、流量历时曲线法、双累积曲线法等方法对黄河干流陕县站和河口镇站1919—2010年径流量演变过程进行了分析。结果表明:区域面平均降水量趋势性变化不显著,而上游（河口镇站以上）及中游（河口镇—陕县）年径流量自1985年以来呈显著减少趋势,中游径流量的降幅高于上游。黄河径流量变化具有明显阶段性,上游和中游径流量变化都经历了枯水期—丰水期—枯水期3个时期,现在黄河正处于枯水期。采用双累积曲线法,定量分析降水和人类活动对径流量的影响,上游和中游人类活动对径流量减少的影响程度分别占88.1%和84.9%,水利水保工程、生产生活用水等人类活动是引起黄河径流量减少的主要因素。  相似文献   

Assessment of urban effect on observed warming trends during 1955–2012 over China: a case of 45 cities     

Kai Jin  Fei Wang  Deliang Chen  Qiao Jiao  Lei Xia  Luuk Fleskens  Xingmin Mu 《Climatic change》2015,132(4):631-643

  相似文献   

内蒙古西部额济纳旗及邻区二叠纪暗色泥岩微量元素和稀土元素地球化学特征   总被引：2，自引：0，他引：2  

宋健  赵省民  陈登超  邓坚  苗忠英  明承栋  陆程 《地质学报》2012,86(11):1773-1780

对泥岩微量元素系统分析表明,额济纳旗及邻区二叠纪整体为半咸水环境;纵向上,二叠纪水体盐度逐渐降低,海水逐渐淡化的过程与裂谷盆地演化消亡的过程同步;横向上,东部（雅干以东）古盐度明显高于西部（北山地区）,这与区内水体东深西浅的沉积古地理格局有关,与古生物分布特征反映的古盐度一致。综合泥岩V/V+Ni、Ceanom分析,认为区内二叠纪整体为缺氧、还原环境,该环境有利于有机质保存;区内水体的还原性西强东弱,北强南弱,其特征控制着该区有机质的分布,这对进一步寻找潜在有利烃源岩具有一定的指导意义。综合泥岩稀土元素配分模式及野外地质调查资料分析表明,区内泥岩的原始物质应来自上地壳,其母岩可能为花岗岩和粘土岩的混合成因。  相似文献   

新疆西天山霍尔果斯岩浆岩带成矿地质条件分析          下载免费PDF全文

张全  高洪生  胡醒民 《地质找矿论丛》2014,29(3):336-343

新疆霍尔果斯岩浆岩带广泛出露晚石炭世—早白垩世侵入岩,文章通过对岩带中晚石炭世混源序列含斑含黑云母二长花岗岩的岩石学、岩石化学、岩石地球化学等特征进行分析与对比研究,并结合其成矿构造背景、地质建造、岩浆活动、岩石类型、蚀变矿化等特征,确定了霍尔果斯岩带内的找矿靶区。  相似文献