Assessing urban flood and drought risks under climate change,China     

Chen Liang  Dingqiang Li  Zaijian Yuan  Yishan Liao  Xiaodong Nie  Bin Huang  Xinliang Wu  Zhenyue Xie 《水文研究》2019,33(9):1349-1361

Risk analysis of urban flood and drought can provide useful guidance for urban rainwater management. Based on an analysis of urban climate characteristics in 2,264 Chinese cities from 1958 to 2017, this study evaluated urban flood and drought risks. The results demonstrated that the annual average values of precipitation, aridity index, frequency and intensity of extreme precipitation and extreme drought events differed significantly in these cities. The values of the above six climatic indicators in the cities ranged from 9.29–2639.30 mm, 0.47–54.73, 1.08–8.79 time, 7.82–107.25 mm, 0.76–2.99 time, and 10.30–131.19 days, respectively. The geographical patterns of urban precipitation, aridity index, intensity and frequency of extreme precipitation and drought events in China fit well to the Hu‐Huanyong Line that was created in 1940s to identify the pattern of population distribution. Extreme precipitation in most cities has upward trends, except for those around the Hu‐Huanyong Line. The extreme drought events had upward trends in the cities east of the Hu‐Huanyong Line, but there were downward trends in the cities west of the line. The risk assessment indicated that 3.80% cities were facing serious flood and 6.01% cities were facing serious drought risks, which are located in the coast of southern China and northwestern China, respectively, and other 90.19% cities were facing different types of drought and flood risks in terms of their intensity and frequency.  相似文献   

Determination of the local tidal parameters for the Borowiec station using Satellite Laser Ranging data     

Jagoda  Marcin  Rutkowska  Miłosława 《Studia Geophysica et Geodaetica》2019,63(4):509-519

Studia Geophysica et Geodaetica - The values of regional tidal parameters h2, l2 associated with the tidal variations of ground stations were estimated for the Polish Satellite Laser Ranging (SLR)...  相似文献   

Numerical SHPB Tests of Rocks Under Combined Static and Dynamic Loading Conditions with Application to Dynamic Behavior of Rocks Under In Situ Stresses     

J. B. Zhu  Z. Y. Liao  C. A. Tang 《Rock Mechanics and Rock Engineering》2016,49(10):3935-3946

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中国地图上应标注的藏南重要地名——巴昔卡   总被引：1，自引：0，他引：1  

郝晓光  廖小韵  胡小刚  徐汉卿  吴鹏飞  刘根友 《大地测量与地球动力学》2010,30(Z1)

对藏南地名——巴昔卡进行了研究与考证。介绍了巴昔卡作为中国雨都和雅鲁藏布大峡谷末端的基本情况,并根据汉藏语系中的珞巴语的特点,将巴昔卡的珞巴语含义推测为雅鲁藏布江边;强调了在《中国地图》上标注藏南地名点巴昔卡的重要性。  相似文献   

黄河入海悬沙季节输送变化与输送机制的数值研究(英文)     

李国胜  王海龙  廖和平 《地理学报(英文版)》2010,20(6):923-937

Based on sediment and discharge flux data for the Yellow River, realistic forcing fields and bathymetry of the Bohai Sea, a suspended sediment transport module is driven by a wave-current coupled model to research seasonal variations and mechanisms of suspended load transport to the Bohai Sea. It could be concluded that surface sediment concentration indicates a distinct spatial distribution characteristic that varies seasonally in the Bohai Sea. Sediment concentration is rather high near the Yellow River estuary, seasonal variations of which are controlled by quantity of sediment from the Yellow River, suspended sediment concentration reaches its maximum during summer and fall. Furthermore, sediment concentration decreases rapidly in other seas far from the Yellow River estuary and maintains a very low level in the center of the Bohai Sea, and is dominated by seasonal variations of climatology wind field in the Bohai Sea. Only a small amount of sediments imported from the Yellow River are delivered northwestward to the southern coast of the Bohai Bay. Majority of sediments are transported southeastward to the Laizhou Bay, where sediments are continuously delivered into the center of the Bohai Sea in a northeastward direction, and part of them are transported eastward alongshore through the Bohai Strait. 69% of sediments from the Yellow River are deposited near the river delta, 31% conveyed seaward, within which, 4% exported to the northern Yellow Sea through the Bohai Strait. Wind wave is the most essential contributor to seasonal variations of sediment concentration in the Bohai Sea, and the contribution of tidal currents is also significant in shallow waters when wind speed is low.  相似文献   

黄河入海泥沙悬移输送机制的控制试验(英文)     

李国胜  黄薛华  刘英  王海龙  廖和平 《地理学报(英文版)》2010,20(1):49-63

Five diagnostic experiments with a 3D baroclinic hydrodynamic and sediment transport model ECOMSED in couple with the third generation wave model SWAN and the Grant-Madsen bottom boundary layer model driven by the monthly sediment load of the Yellow River, were conducted to separately diagnose effects of different hydrodynamic factors on transport of suspended sediment discharged from the Yellow River in the Bohai Sea. Both transport and spatio-temporal distribution of suspended sediment concentration in the Bohai Sea were numerially simulated. It could be concluded that suspended sediment discharged from the Yellow River cannot be delivered in long distance under the condition of tidal current. Almost all of sediments from the Yellow River are deposited outside the delta under the condition of wind-driven current, and only very small of them are transported faraway. On the basis of wind forcing, sediments from the Yellow River are mainly transported north-northwestward, and others which are first delivered to the Laizhou Bay are continuously moved northward. An obvious 3D structure characteristic of sediment transport is produced in the wind-driven and tide-induced residual circulation condition. Transport patterns at all layers are generally consistent with circulation structure, but there is apparent deviation between the depth-averaged sediment flux and the circulation structure. The phase of temporal variation of sediment concentration is consistent with that of the bottom shear stress, both of which are proved to have a ten-day cycle in wave and current condition.  相似文献   

有利环流形势下北京降雪空报原因     

魏东  廖晓农  杨波 《四川地震》2010,(1)

利用常规资料及微波辐射计、风廓线等新型探测资料,分析了2007年2月7日当大尺度环流形势非常有利并且华北东部地区出现大范围降雪的情况下,京津地区未产生降水及导致预报失误的主要原因。大范围环流形势演变分析结果表明,700 hPa以上辐合系统前部的偏南气流将水汽输送到降水区,且回流冷空气形成的冷楔和华北倒槽提供了有利的背景条件。弱冷空气南压导致倒槽填塞没有影响京津地区而且边界层内辐合系统产生的上升气流较弱是造成京津绝大部分地区未出现降水的原因之一。大湿度区层次高、湿层薄是北京城区没有降雪的另一重要原因。造成此次降雪空报的主要原因是:数值模式对边界层相对湿度预报过高,且时效间隔较长、其间的天气形势难以判断;不利于降雪的实况信息显现得过晚。北京东部个别测站出现降水的可能原因是在短时回流条件具备的同时有高空槽过境,但动力抬升条件差。在较强偏南暖湿气流提供水汽的同时,海拔高、水汽易于凝结是北京西北部的几个较高海拔测站出现降雪的原因。  相似文献   

福建闽清梅埔井水位异常判识     

廖丽霞  刘其寿  郑永通  陈莹 《地震地磁观测与研究》2010,31(4):51-56

根据地下流体前兆异常落实工作指南,对福建闽清梅埔井水位大幅下降的成因作分析,通过观测技术系统故障、水口水库排水干扰、趋势动态、抽水干扰等因素的排除,认为闽清梅埔井水位呈规律性下降是固体潮固有韵律,非外界干扰引起;而水位大幅下降则有可能是区域应力情况的真实反映,可能反映了井区周围断裂活动的加剧。  相似文献   

Internal reflection pattern of Korea Strait shelf mud (Nakdong River subaqueous delta) off southeast Korea and implications for Holocene relative base-level change     

Gwang H.  Lee  Dae C.  Kim  Mi K.  Park  Soo C.  Park  Han J.  Kim  Hyeong T.  Jou  Boo K.  Khim 《Island Arc》2010,19(1):71-85

The Korea Strait shelf mud (KSSM) (Nakdong River subaqueous delta) is the most conspicuous Holocene sedimentary feature in the inner shelf off southeast Korea. Analysis of multi-channel sparker profiles and ¹⁴C ages of sediment cores reveals that the KSSM consists of three seismic units at the depocenter (>60 m thick): (i) the thin transgressive bottom (> ca 8000 cal bp ); (ii) thick (>40 m) obliquely progradational middle ( ca 8000– ca 2600 cal bp ); and (iii) thin transgressive top ( ca 2600 cal bp –present) units. The relative base level, predicted from the internal reflection pattern of the KSSM, remained significantly deeper (up to >70 m) than global sealevel during much of the Holocene. The apparent gradual drop (∼20 m) of the relative base level during the deposition of the middle unit, followed by a rise, further suggests that base level does not conform to sealevel and is more sensitive than the relative sealevel is to the local oceanographic regime and processes.  相似文献   

赣南葛廷坑钼矿辉钼矿Re-Os年龄及其地质意义   总被引：1，自引：0，他引：1       下载免费PDF全文

吴俊华  赵赣  屈文俊  袁承先  龚敏  刘爽  李牟  周雪桂  廖明和  魏俊浩  马振东 《地学前缘》2011,18(3):261-267

赣南葛廷坑钼矿为产在花岗斑岩与围岩内外接触带的中型斑岩型钼矿床。通过对矿区含矿石英脉中7个辉钼矿样品进行Re Os同位素测定,获得等时线年龄及模式年龄的加权平均值分别为(1594±16)和(1588±13) Ma。等时线初始187Os为(0001±0055)ng/g,MSWD=17。葛廷坑钼矿形成于中侏罗世中晚期,其成矿年龄对应于华南中晚侏罗世第二成矿阶段(170～150 Ma),与区域内160 Ma左右的钨锡矿成矿作用基本一致。区域上华南钼的成矿时间具有连续性,在165～90 Ma均有发生。  相似文献