塘沽海洋站水位变化及其极值与海面风的相关关系研究

在海洋工程设计中,水位极值是一个重要的设计参数。对塘沽海洋站54a每小时的水位观测资料(1950—2003)和38a的海面风观测资料(1965—2003)进行了分析,探讨了该站水位的变化特征及海面风与水位极值的相关关系。分析结果表明,在水位时间序列中M2分潮占总能量的60%以上,六个主要分潮M2,S2,N2,K2,K1和O1占总能量的93%以上。年平均海平面的变化并不是简单的线性变化,而是存在3~5a的周期性波动,这可能与厄尔尼诺、太阳黑子活动和交点周期等周期性和准周期性变化过程有关。由54a实测资料计算得的年平均海平面的年变率为1.64mm/a。54a中最高水位为5.81m,发生在1992年9月;最低水位为-0.99m,发生在1968年11月。100a一遇的最高水位为6.02m,由偏东向风引起,而西向风引起塘沽海洋站减水。对于100a一遇的各向最大风速,北向偏东风的100a一遇的风速为最大,其值为26.78m/s,其可能引起的最大增水为2.06m。西风的100a一遇最大风速为20.5m/s,其可能引起的减水水位为2.28m。     

橄榄坝水电站水库浸没问题分析评价

针对橄榄坝电站所处的地理位置,并结合水库运行特征,选定了水库特征水位对该水库的浸没问题进行分析评价,同时根据云南滇池、阳宗海等内陆湖泊对周边浸没影响的调查,将浸没区按浸没影响程度不同分为严重浸没区、中等浸没区和轻微浸没区,并对不同的浸没区提出了处理措施建议。     

Recent lake level variations in Lake Haubi, central Tanzania, interpreted from pollen and sediment studies

Variations in pollen assemblages and in physical and chemical composition of a dated sediment record from the small Lake Haubi in north central Tanzania, reveal lake level fluctuations since the late 19th century. Lake Haubi changed from a seasonally inundated swamp to a lake in the beginning of the 20th century. With the exception of 1942-44, when it dried out completely, it remained water filled until 1994 when it again turned into a swamp. The lake level fluctuations in Lake Haubi are largely in phase with fluctuations of the larger East African lakes levels during the 20th century, and are therefore interpreted as being mainly controlled by regional climatic fluctuations. However, the initial formation of Lake Haubi at the turn of the century was likely due to local catchment specific causes, e.g. changes in land use, as the rapid increase in the water level at this time does not correspond to other lake level records from the region.     

Impacts of climate change on groundwater recharge in Küçük Menderes River Basin in Western Turkey

Groundwater is an important component of the global freshwater supply and is affected by climate. There is a strong need to understand and evaluate the impacts of climate change over the long term, in order to better plan and manage precious groundwater resources. Turkey, located in Mediterranean basin, is threatened by climate change. The purpose of this study was, through a quantitative overview, to determine the impacts of climate change on the groundwater recharge rates in Küçük Menderes River Basin in western Turkey. According to the data of Ödemi? and Selçuk meteorological stations located in the basin, there is a significantly decreasing trend in precipitation combined with increasing trends in temperature and evaporation observed in 1964–2011. The calculations of groundwater recharge with hydrologic budget method for the observation period showed an approximately 15% decline in groundwater recharge in the basin. Thus, the combined impacts of climate change and excessive groundwater pumping, due to increasing water demand, have caused a significant decline in groundwater levels. Consequently, the proper management of the groundwater resources threatened by climate change requires effective governance to both mitigate the adverse impacts of climate change and facilitate the adaptation of sustainable integrated water management policies.     

Storm extreme levels and coastal flood hazards: A parametric approach on the French coast of Languedoc (district of Leucate)

Coastal flooding is a significant risk on the shores of Languedoc-Roussillon. The storms that periodically hit the coast can generate strong swells and storm surges. Most beach resorts, built on a low elevation dune ridge, are periodically flooded during major storms. Although risks zoning regulations take into consideration coastal flood hazards, the delineation of vulnerable areas is still insufficient and the commonly accepted threshold is regularly exceeded during most severe storms. This paper presents a method to improve the assessment of extreme storm-related water levels. It relies on fieldwork carried out in the Leucate commune (Aude), which is particularly exposed to the risk of sea level rise. It considers both storm surges and wave phenomena that occur within the surf zone (set-up and swash), calculated from the Simulating WAves Nearshore (SWAN^®) numerical wave model and the Stockdon formula. Water levels reached during several recent storm events have been reconstructed and simulations of submerged areas were carried out by numerical modelling.     

1951-2006年黄河和长江流域雨涝变化分析

 根据1951-2006年黄河和长江流域雨涝灾害灾情统计资料,分析了两个流域雨涝灾害发生频率的时空分布特征,结果表明：近50 a以来,特别是20世纪80年代以来,受气候变化影响,黄河和长江流域雨涝灾害不断增加,农作物受灾、成灾面积呈增加趋势,损失日趋严重,且长江流域受雨涝灾害影响范围较大,灾害发生频率大于黄河流域。受暴雨影响,夏季两个流域雨涝发生频率最高、范围最广。20世纪80年代末以来,黄河流域雨涝灾害增加趋势较为明显,而长江流域80年代初雨涝受灾面积和成灾面积显著增加。两个流域雨涝灾害的受灾率均自上游至下游逐渐增加,其中长江流域中下游地区受雨涝灾害影响较大。     

Effect of strong magnetic field on cosmic quark-hadron phase transition and baryon inhomogeneity

The effect of intense magnetic field on the cosmic quark-hadron phase transition and also on the baryon number inhomogeneity has been investigated using phenomenological MIT bag model for the quark sector. For the sake of simplicity an ideal gas equation of state has been considered for the hadronic phase.     

The application of integrated urban inundation model in Republic of Korea

In urban areas with a high building density, features such as roads, buildings and river dykes significantly affect flow dynamics and flood propagation. This should therefore be accounted for in the model set‐up. While 2D hydraulic models of densely urban areas are at the forefront of current research into flood inundation mechanisms, these models are constrained by inadequate parameters of topography and insufficient data. In order to solve these problems, topographic information obtained from digital elevation model (DEM) is directly programmed into the urban inundation model for a densely urban area, without exchanging the input data. In this paper, the extraction of building area is described using a tight coupling approach within a GIS environment, and its influence on the extent of flood inundation with a high building density is estimated. Copyright © 2009 John Wiley & Sons, Ltd.     

Correlation between coastal geomorphology and tsunami inundation along the coast of Kanyakumari, India

An investigation has been carried out in the vicinity of the coastal villages of Kanyakumari District,India to decode the influence of coastal geomorphology on inundation degree and run-up level.Even though the tsunami waves approach the study area in different patterns,the consequences are found to be mainly dependent upon the coastal configuration and local geographic setting,the study area are considered to be of three types based upon the geomorphic arrangement,namely shallow coast,elevated coast and estuarine coast.The inundation and run-up level vary from coast to coast even though there is no remarkable variation in the intensity of the approaching tsunami surge.The inundation extent ranges from to 54 m to 413 m with maximum along estuarine coast and minimum along elevated coast.Estuarine coast recorded the maximum run-up level of about 6 m and the minimum of about 1 m along the elevated coast.The percentage of inundated area in the total coastal area varies between 19% to 10% along estuarine coast and elevated coast respectively.Inundation and run-up level cannot be appreciable in the inland along the elevated coast.The beaches of elevated coast are less affected whereas those of estuarine coast are highly affected.Inundation is limited in the elevated beaches along the study area.