珠江三角洲治水方针的实施和发展

珠江三角洲网河区治水方针从联围筑闸、以防为主,到合理导治、以泄为主,再到近期以清障为主。联围筑闸,利多弊少。洪水位长期呈上升趋势,但堤围的标准偏低。十余年来,口门的水沙分配发生了很大变化,口门整治必须合理围垦和适当疏浚。三角洲腹心地区洪峰水位异常壅高,主要是由于北江的分流比增大。近期有必要清除河障,疏浚主干河道,但是长远之计是兴建思贤和南华水闸,调控西江、北江的流量,确保防洪安全。     

低空遥感影像匹配与拼接技术研究

介绍了无人驾驶飞行器低空遥感的优势和特点,阐述了低空遥感影像的自动匹配及全景图拼接方法,试验结果验证了其匹配和全景影像图自动拼接方法的正确性。     

Sulphate generation in South African underground and opencast collieries

Deterioration in the water quality results from coal mining, and the significant impact on the environment in South Africa has been reported (Funke in SA Water, Sci Technol 15:115–144; 1983). Pyrite in with South African coal can be oxidised to yield acidic and high salinity water. This study deals with the rate at which sulphate could be produced for collieries under different conditions. Four collieries in the Witbank coalfield were selected for this investigation. The boreholes were investigated with an in-situ multi-parameter probe, and then sampled at different times with a specific depth sampler to determine the chemical composition of the water in the collieries. Water level measurements and volumetric calculations were done to determine influx rates. Daily sulphate generation rate for underground mining was found to be in the range of 0.4–2.7 kg/ha, depending on the availability of oxygen and the residence time of the water (the time available for neutralising agents present to react) in the mining void. The exclusion of oxygen due to flooding and the presence of calcareous carbonates influences the observed sulphate generation.     

Climatic effects on ice phenology and ice-jam flooding of the Athabasca River in western Canada

ABSTRACT

In cold region environments, any alteration in the hydro-climatic regime can have profound impacts on river ice processes. This paper studies the implications of hydro-climatic trends on river ice processes, particularly on the freeze-up and ice-cover breakup along the Athabasca River in Fort McMurray in western Canada, which is an area very prone to ice-jam flooding. Using a stochastic approach in a one-dimensional hydrodynamic river ice model, a relationship between overbank flow and breakup discharge is established. Furthermore, the likelihood of ice-jam flooding in the future (2041–2070 period) is assessed by forcing a hydrological model with meteorological inputs from the Canadian regional climate model driven by two atmospheric–ocean general circulation climate models. Our results show that the probability of ice-jam flooding for the town of Fort McMurray in the future will be lower, but extreme ice-jam flood events are still probable.     

Prehistorical frequency of high‐energy marine inundation events driven by typhoons in the Bay of Bangkok (Thailand), interpreted from coastal carbonate boulders

Rapidly rising populations of low‐lying megacities in Asia mean that understanding the potential risk of coastal flooding by storm surge is of paramount concern. The city of Bangkok and the wider Chao Phraya River delta at the head of the Gulf of Thailand is a region topographically vulnerable to coastal flooding, but without the record of a high‐energy marine inundation (HEMI) event in historical time owing to the atypical path that a typhoon must take to be able to produce such an event. This work builds upon previous findings that identified coastal depositional evidence for HEMI events in the form of coastal carbonate boulders (CCBs) located on Ko Larn Island in the eastern Bay of Bangkok. The HEMI events were most likely driven by typhoons and the CCBs are therefore interpreted as typhoon deposits. Through uranium/thorium dating, it is revealed that from ad 1400 to ad 1600 the Bay of Bangkok possibly experienced a phase of relatively heightened storm impact. During this period, the frequency of typhoon‐driven HEMI events was approximately four events in 200 years. Waves generated onshore minimum flow velocities (MFVs) in excess of 5 m/s. Such exceptional MFVs are unlikely to be produced during the annual northeast monsoon, but are consistent with typhoon‐impacted coastlines elsewhere in the tropical Asia–Pacific region where similar CCB evidence exists. Since ad 1600, the Bay of Bangkok has enjoyed a relatively quiescent phase, recording less frequent HEMI events and of lower magnitude. However, the re‐occurrence of a typhoon‐driven HEMI event on the scale of the prehistorical events that emplaced carbonate boulders at elevation on Ko Larn Island would threaten low‐lying coasts in the Bay of Bangkok, including the Chao Phraya delta, with potentially damaging inundation. Copyright © 2015 John Wiley & Sons, Ltd.     

江淮平原水网区汛期雨量与洪涝水位关系——以江苏里下河腹部地区为例

利用江苏里下河腹部地区8个雨量站和5个水位站1957～2006年的50年气象水文资料,采用Mann-Kendall方法检验面雨量变化趋势,并应用Pearsorl和Spearman方法揭示雨量同水位的相关关系.结果表明:近50年来汛期面雨量、单站雨量和时段雨量的长期变化都呈减小趋势.最大15日和最大3日雨量是水位变化的敏...     

氢化物发生-原子荧光光谱法测定土壤中水溶态和可交换态锑(Ⅲ)和锑(Ⅴ)

在0.10 mol/L酒石酸介质中,采用氢化物发生-原子荧光光谱法测定土壤中水溶态和可交换态Sb(Ⅲ)和Sb(Ⅴ)。以氢气发生器为氩-氢火焰提供氢气,明显降低了硼氢化钾浓度,改善了测定检出限。考察了酒石酸掩蔽Sb(Ⅴ)的量及共存干扰元素的允许量。方法检出限Sb(Ⅲ)为0.026 ng/L,总Sb为0.019 ng/L。加标回收试验表明,方法准确、可靠。     

河口涨潮槽的研究进展

河口涨潮槽是河口的重要地貌单元。对河口涨潮槽的发育过程与演化规律的研究在理论上可以丰富河口动力地貌的内容，而在实践上对港口和通航等具有重要的意义。文章认为河口涨潮槽不仅指河口涨潮流作用下形成的冲刷槽，还包括涨潮冲刷坑、涨潮冲刷槽和涨湖水道。国内外关于河口涨潮槽研究较为薄弱，研究内容多集中于涨潮槽的几何形态、涨落槽优势流判别和悬沙输移等方面，定性研究较多，缺乏全面而系统的定量研究，尤其缺乏成因机制方面的深入研究和沉积环境的研究。长江口涨潮槽种类较多，具有一定的研究基础，对其进行系统全面的研究具有重要的意义。     

上海外滩防汛墙的高度

本文提出上海外滩防汛墙的建立及以后几次加高主要是上海城市地面沉降引起的。防汛墙安全递增率随时间、地点而不同,其决定性因素为地面沉降率和海面上升率。祗有在地面基本稳定的条件下,上海市区防汛墙的高度才主要取决于气象、风暴潮引起的高潮位。     

东北春夏季降水气温异常的时空分布以及与旱涝的关系

利用东北地区19个测站的1951--2000年逐月降水、气温资料，采用综合的经验正交函数展开等诊断方法，研究了春、夏季节降水、气温异常的空间分布特征、时间变化规律以及与旱涝年份之间的关系。结果表明，所得到的降水、气温异常的典型配置场及其时间系数能较好地反映东北地区降水、气温异常的时空特征，且夏季时间系数出现极值的年份与东北地区不同区域发生较严重旱涝的年份存在很好的对应关系。