基于遥感技术对黄河口水色与岸线季相变化特征研究     

马安青  胡泓  袁道伟  胡婷 《中国海洋大学学报(自然科学版)》2008,38(1):151-156

使用Landsat-5 TM 2004年11月24日与2005年5月13日黄河口遥感影像,配合准同期外业实测资料,进行黄河口水体水色物质叶绿素a与悬浮泥沙的动态反演与河口岸线解译.研究表明由于秋末与春初黄河上游来水物质含量的差异,上述悬浮指标值存在显著的季相差异.根据样值与光谱特征建立的反演模型得出的反演值与实测值有平均在0.85以上的相关关系,具有很好的反演效果.岸线解译成果表明,黄河口岸线演变迅速,在河流平枯水量时期仍然具有较强的变化,岸线推进尤以新河口附近显著.这表明,使用遥感手段是进行河口生态环境质量监测的有效手段,是进行岸线动态变化研究的一种基本技术支撑手段.  相似文献   

AREAL DIFFERENTIATION AND CONSTRUCTION OF OASIS AGRICULTURAL ECOSYSTEM IN THE SHIYANG RIVER BASIN     

张维祥  梁智睿 《中国地理科学(英文版)》1993,3(4):357-364

On the basis of the study on areal differentiation of the natural environment of oasis agriculture ecosystems in the Shiyang River Basin, this paper comparatively analyzes the natural productivities, water economic benefits, production efficiency, ecological stabilities and developmental conditions of the Wuwei Oasis agricultural ecosystem in the middle reaches of the river basin and the Minqin Oasis agricultural ecosystem in the lower reaches. Under a same management level and investment of . material and energy, primary productiveness and economic benefits of the former are higher than those of the latter. Construction directions of Wuwei and Minqin oases should be different in order to alleviate the water- use contradiction between the middle and lower reaches. The construction objective of Wuwei Oasis should be efficient irrigated farming production system and Minqin Oasis should become a mixed forestry-pastoral-farming ecosystem taking ecological protection as its major function.  相似文献   

IMPACTS OF FUTURE SEA LEVEL RISE ON SALT WATER INTRUSION IN THE CHANGJIANG RIVER ESTUARY   总被引：1，自引：0，他引：1  

杨桂山 《中国地理科学(英文版)》1992,2(1):30-41

Sea level rise could increase the salinity of an estuary by altering the balance between fresh water and salt water. The implications of sea level rise for increasing salinity have been examined in the Changjiang (Yangtze) River estuary. By correlative analysis of chlorinity, discharge and tidal level and calculation of two-dimensional chlorinity, distribution of the Changjiang River estuary, the changes of the intensity and lasting hours of salt water intrusion at Wusong Station and the changes of chlorinity distribution in the South Branch of the Changjiang River estuary have been estimated when future sea level rises 50-100 cm. The intensity of salt water intrusion in the future will be far more serious than current trend.  相似文献   

Is Precipitation the Dominant Controlling Factor of High Inorganic Nitrogen Content in the Changjiang River and Its Mouth？   总被引：1，自引：1，他引：0  

沈志良 《中国海洋湖沼学报》2003,21(4):368-376

The main reasons for the high content of inorganic N and its increase by several times in the Changjiang River and its mouth during the last 40 years were analysed in this work. The inorganic N in precipitation in the Changjiang River catchment mainly comes from gaseous loss of fertilizer N, N resulting from the increases of population and livestock, and from high temperature combustions of fossil fuels. N from precipitation is the first N source in the Changjiang River water and the only direct cause of high content of inorganic N in the Changjiang River and its mouth. The lost N in gaseous form and from agriculture non-point sources fertilizer comprised about 60% of annual consumption of fertilizer N in the Changjiang River catchment and were key factors controlling the high content of inorganic N in the Changjiang River mouth. The fate of the N in precipitation and other N sources in the Changjiang River catchment are also discussed in this paper.  相似文献   

FUZZY COMPREHENSIVE EVALUATION OF CONTAINER TRANSPORTATION MODES ALONG THE CHANGJIANG RIVER MAIN LINE AND ITS DELTA AREA   总被引：1，自引：0，他引：1  

ZHANGShi-yu XIAOHan-liang 《中国地理科学(英文版)》2003,13(3):259-261

The Changjiang River (Yangtze) is one of the fastest growth areas of container transportation in Chi-na. Rail, road and water transportation have competed against each other for container transportation in the Chang-jiang River main line and its delta area. It is of significance to assess these different transportation modes scientifi-cally in order to organize container transportation efficiently in this area and make decision for integral plan and construction of transportation system in this area. This paper outlines application of fuzzy comprehensive evaluation to appraise different modes of typical direction of containers. Twelve assessment indexes were decided. Membership functions were formulated. Evaluation results indicated that road transportation was optimal mode in the Changjiang River delta area, however water transportation was the primary way in the Changjiang River main line.  相似文献   

长江三峡工程地壳形变监测网络   总被引：19，自引：10，他引：9  

邢灿飞  龚凯虹  杜瑞林 《大地测量与地球动力学》2003,23(1):114-118

长江三峡工程地壳形变监测网络，采用了当今高精度GPS、INSAR空间大地测量技术，并与精密水准测量，精密重力测量，精密激光测距和峒体连续形变监测等技术相结合，构成一个空间上点、线、面结合，时间上长、中、短兼顾的高精度，高时空分辨率的地壳形变监测网络。该网络既可获取三峡库区特别是库首区区域形变场和区域应变场的动态变化，监测库区主要断层活动，为水库诱发地震预测及研究服务，又可用于气象、滑坡地质灾害监测等，该监测网络于1997年底开始建设，2001年6月建成，到目前为止，已获得大量宝贵的观测资料，必将产生显著的经济效益和社会效益。  相似文献   

澜沧江云南德钦古水一带第四纪堰塞湖的沉积特征及其环境意义     

张永双  赵希涛 《地质学报》2008,82(2):262-268

在云南省西北部德钦县古水一带深切的澜沧江河谷中,发现了一套第四纪湖相沉积物,以纹层状粘土、粉砂质粘土和粉砂的互层组合为特征,构成了第三和第四级阶地的基座.笔者对该湖相剖面进行了U系、孢粉和若干地球化学指标的分析测试,并以这些结果讨论了古湖的形成时代和成因,以及古湖堆积时期的古植被和古气候.剖面顶部、中部和中下部粘土的U系法年龄测定结果分别为52.3±3.4 ka、64.2±5.6 ka和81.9±6.5 ka,说明古水古湖形成于晚更新世早中期的末次间冰期晚期和末次冰期的早冰阶与间冰阶早期,很可能是大型冰川(如下游的明永冰川等)或巨量的冰水沉积物堰塞了澜沧江河谷而造成的结果.  相似文献   

Heavy metals in sediments of the Tecate River, Mexico   总被引：1，自引：0，他引：1  

F. T. Wakida  D. Lara-Ruiz  J. Temores-Peña  J. G. Rodriguez-Ventura  C. Diaz  E. Garcia-Flores 《Environmental Geology》2008,54(3):637-642

Ten sites along the Tecate River, Mexico were sampled to evaluate the cadmium, lead, nickel and chromium concentrations in sediments. The result shows contamination for cadmium in most of the sites, where two sites were class 4 (polluted to strongly polluted) according to geoaccumulation index proposed by Muller. Two sites were found polluted for all the heavy metals analyzed (Cr, Cd, Pb and Ni), indicating the effect of anthropogenic activities. A correlation between Ni and Cd concentration had been found indicating a common source. These metals are usually used in electroplating industry. The results of this study can be used for decision makers to prioritize measures to control the pollution for these metals.  相似文献   

Response of groundwater chemistry to water deliveries in the lower reaches of Tarim River,Northwest China   总被引：2，自引：0，他引：2  

Yongjin Chen  Kefa Zhou  Yaning Chen  Weihong Li  Jiazhen Liu  Tao Wang 《Environmental Geology》2008,53(6):1365-1373

In this paper, we analysed the monitored data from nine groundwater-monitoring transects in the lower reaches of Tarim River during the five times of stream water deliveries to the river transect where the stream flow ceased. The results showed that the groundwater depth in the lower reaches of Tarim River rose from −9.30 m before the conveyances to −8.17 and −6.50 m after the first and second conveyances, −5.81 and −6.00 m after the third and fourth the conveyance, and −4.73 m after the fifth. The horizontal extent of groundwater recharge was gradually enlarged along both sides of the channel of conveyance, i.e., from 250 m in width after the first conveyance to 1,050 m away from the channel after the fourth delivery. With the rising groundwater level, the concentrations of major anions Cl⁻, SO₄²⁻ and cations Ca²⁺, Mg²⁺, Na⁺, as well as total dissolved solids (TDS) in groundwater underwent a significant change. The spatial variations in groundwater chemistry indicated that the groundwater chemistry at the transect near Daxihaizi Reservoir changed earlier than that farther from it. In the same transect, the chemical variations were earlier in the monitoring well close to watercourse than that farther away from the stream. In general, the concentration of the major ions and TDS at each monitoring well increased remarkably when the water delivery started, and decreased with the continued water delivery, and then increased once again at the end of the study period. Hence, the whole study period may be divided into three stages: the initial stage, the intermediate stage and the later stage. According to the three stages of groundwater chemistry reaction to water delivery and the relationships between groundwater chemical properties and groundwater depths, we educe that under the situation of water delivery, the optimum groundwater depth in the lower reaches of the Tarim River should be −5 m.  相似文献   

Natural radioactivity in sediment of Wei River,China   总被引：1，自引：0，他引：1  

Xinwei Lu  Xiaolan Zhang  Fengling Wang 《Environmental Geology》2008,53(7):1475-1481

The concentrations of natural radionuclides in sediment of Wei River of China were measured using γ-ray spectrometry with the aim of estimating the radiation hazard as establishing a database for radioactivity levels of river sediment of China. The activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in sediment samples ranged from 10.4 to 39.9 Bq kg⁻¹, 15.3 to 54.8 Bq kg⁻¹ and 514.8 to 1,175.5 Bq kg⁻¹, respectively. The concentrations of these radionuclides were compared with the typical world values and the average activities of Chinese soil and Shaanxi soil. Radium equivalent activity (Ra_eq), external hazard index (H _ex) and representative level index (I _γr) were calculated for the samples to assess the radiation hazards arising due to the use of these sediment samples in the construction of dwellings. All the sediment samples have Ra_eq lower than the limit of 370 Bq kg⁻¹, H _ex less than unity and I _γr close to 1 Bq kg⁻¹. The overall mean outdoor terrestrial gamma dose rate is 64.8 nGy h⁻¹ and the corresponding outdoor annual effective dose is 0.079 mSv. None of the studied location is considered a radiological risk and sediment can be safely used in construction.  相似文献