Covariation of the Indonesian Throughflow and South China Sea Throughflow Associated with the 1976/77 Regime Shift   总被引：4，自引：0，他引：4  

LIU Qinyan  WANG Dongxiao  ZHOU Wen  XIE Qiang  ZHANG Yan 《大气科学进展》2010,27(1):87-94

Changes in the Indonesian Throughflow(ITF) and the South China Sea throughflow—measured by the Luzon Strait Transport(LST)—associated with the 1976/77 regime shift are analyzed using the Island Rule theory and the Simple Ocean Data Assimilation dataset.Results show that LST increased but ITF transport decreased after 1975.Such changes were induced by variations in wind stress associated with the regime shift.The strengthening of the easterly wind anomaly east of the Luzon Strait played an important role in ...  相似文献   

Long‐wave radiation and heat flux estimates within a small tributary in Catamaran Brook (New Brunswick,Canada)     

Loubna Benyahya  Daniel Caissie  Mysore G. Satish  Nassir El‐Jabi 《水文研究》2012,26(4):475-484

River water temperature is an important water quality parameter that also influences most aquatic life. Physical processes influencing water temperature in rivers are highly complex. This is especially true for the estimation of river heat exchange processes that are highly dependent on good estimates of radiation fluxes. Furthermore, very few studies were found within the stream temperature dynamic literature where the different radiation components have been measured and compared at the stream level (at microclimate conditions). Therefore, this study presents results on hydrometeorological conditions for a small tributary within Catamaran Brook (part of the Miramichi River system, New Brunswick, Canada) with the following specific objectives: (1) to compare between stream microclimate and remote meteorological conditions, (2) to compare measured long‐wave radiation data with those calculated from an analytical model, and (3), to calculate the corresponding river heat fluxes. The most salient findings of this study are (1) solar radiation and wind speed are parameters that are highly site specific within the river environment and play an important role in the estimation of river heat fluxes; (2) the incoming, outgoing, and net long‐wave radiation within the stream environment (under the forest canopy) can be effectively calculated using empirical formula; (3) at the study site more than 80% of the incoming long‐wave radiation was coming from the forest; (4) total energy gains were dominated by solar radiation flux (for all the study periods) followed by the net long‐wave radiation (during some periods) whereas energy losses were coming from both the net long‐wave radiation and evaporation. Conductive heat fluxes have a minor contribution from the overall heat budget (<3·5%); (5) the reflected short‐wave radiation at the water surface was calculated on average as 3·2%, which is consistent with literature values. Results of this study contribute towards a better understanding of river heat fluxes and water temperature models as well as for more effective aquatic resources and fisheries management. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Geomorphic controls and transition zones in the lower Sabine River     

Jonathan D. Phillips 《水文研究》2008,22(14):2424-2437

Instream flow science and management requires identification of characteristic hydrological, ecological, and geomorphological attributes of stream reaches. This study approaches this problem by identifying geomorphic transition zones along the lower Sabine River, Texas and Louisiana. Boundaries were delineated along the lower Sabine River valley based on surficial geology, valley width, valley confinement, network characteristics (divergent versus convergent), sinuousity, slope, paleomeanders, and point bars. The coincidence of multiple boundaries reveals five key transition zones separating six reaches of distinct hydrological and geomorphological characteristics. Geologic controls and gross valley morphology play a major role as geomorphic controls, as does an upstream‐to‐downstream gradient in the importance of pulsed dam releases, and a down‐to‐upstream gradient in coastal backwater effects. Geomorphic history, both in the sense of the legacy of Quaternary sea level changes, and the effects of specific events such as avulsions and captures, are also critical. The transition zones delineate reaches with distinct hydrological characteristics in terms of the relative importance of dam releases and coastal backwater effects, single versus multi‐channel flow patterns, frequency of overbank flow, and channel‐floodplain connectivity. The transitional areas also represent sensitive zones which can be expected to be bellwethers in terms of responses to future environmental changes. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

黄河北、章丘、淄博煤田煤层气开发前景     

范士彦  魏怀习等 《中国煤田地质》2001,13(4):27-28

黄河北、章丘、淄埔煤田煤层在深成变质演化的基础上,受岩浆浸入的影响，局部迭加了区域岩浆热变质和接触变质作用，导致煤阶增高，对煤层生气具有重要作用。通过煤层气的基本特征和有利烃源条件的分析，估算了黄河北、章丘、淄博煤田煤层气资源量为1333．31亿m^3，可作为今后勘探开发的目标区。  相似文献   

长江口岸滩近期演变及南水北调工程的可能影响   总被引：5，自引：0，他引：5  

杨世伦  赵庆英  朱骏 《上海国土资源》2001,(2):7-11

根据近几十年长江口前沿滩的地形观测资料和大通站输沙量资料，揭示了入海泥沙量变化对河口前沿岸滩冲淤的重要影响，初步估计：在年调水总量不超过450亿吨的背景下，入海泥沙的减少将＜0．2亿t/a，河口潮滩的冲淤动态不会发生实质性变，但同时指：当南水北调和流域的其它入人类活动叠加时，其影响不容忽视。  相似文献   

河流纵向分散系数研究   总被引：8，自引：1，他引：8       下载免费PDF全文

邓志强  褚君达 《水科学进展》2001,12(2):137-142

研究了天然河流纵向分散系数理论公式及其参数的确定问题.借助于抛物型断面型态方程确定了河道垂线水深沿河宽的分布及流速分布对断面平均流速的偏离u‘的横向分布,给出了横向混合系数计算方法.在此基础上通过对Fischer的三重积分的直接求解,建立了新的天然河流纵向分散系数计算公式.这一新建立的纵向分散系数计算公式与原有的有代表性的经验公式以及26条美国河流上实测的59组资料进行了比较,比较结果表明,本文建立的纵向分散系数计算公式能给出与实测纵向分散系数最接近的预测值.与现有的其它纵向分散系数计算公式相比,本文建立的天然河流纵向分散系数公式理论上更加合理,机理上更加清楚,并且具有最小的预测误差.  相似文献   

基于遗传算法的地下水位动态预测双线性模型   总被引：10，自引：0，他引：10       下载免费PDF全文

金菊良  杨晓华  金保明  丁晶 《水科学进展》2001,12(3):361-366

提出了建立双线性模型(BM)的一套简便通用的方法。用加速遗传算法可同时估计BM 模型各参数,成功地解决了BM建模这一难题,为BM模型的广泛应用提供了新工具。实例计算 结果说明:用这套方法预测地下水位动态是可行而有效的;通过利用预测过程中产生的残差信 息进行反馈矫正,保证了BM模型劫高的拟合精度和稳健的预测性能,增强了对复杂非线性动态 系统的适应性。  相似文献   

宁蒗6．2级地震前丽江井水位异常特征     

和国文 《四川地震》2001,1(1):36-38

1998年11月19日宁蒗发生6．2级地震前，丽江井水位在长中短期、临震阶段出现了较明显的异常。异常的阶段性明显，并随地震的临近其幅度和种类方面逐渐增加。出现了自有观测以来下降幅度和上升幅度最大的破年变异常。短临异常主要表现为突降、固体潮畸变、锯齿波、毛刺、脉冲等。  相似文献   

山西太原西山地区汾河河谷地貌   总被引：2，自引：0，他引：2  

梁全武 《山西地震》2001,(2):6-10

论述了汾河上游六家河-中兰村峡谷段6级河流阶地的特征及形成时代，并在此基础上分析了汾河河谷的发育历史及山西太原西山和太原盆地的新构造差异升降运动的特征。  相似文献   

关于珠江河海划界的意见   总被引：13，自引：2，他引：13  

赵焕庭  王丽荣 《热带地理》2001,21(3):218-222

大河河海划界不能简单地把河流入海由窄变宽的口门断面作为河海分界线。文中分析了大河珠江河口的自然与开发利用的有关情况后，提出主要根据咸水入侵和淡水冲出程度以及生态环境，并参考港口航道、水利和环境监测等因素，划出河口段和河口延伸段。由水行政机关主管河口段和河口延伸段的开发利用、整治和管理的行政事务是适宜的，要大力协调段内所有涉水项目的规划和工程的计划行动。  相似文献