总共搜索到30620条文献 排序方式 从年到年 仅显示OA的文献 |
高原湖泊的演化研究是全球环境研究的重要组成部分,本文以西藏过布错湖泊为研究对象,利用RS、GIS技术,以TM图像为遥感信息源,根据遥感图像上过布错湖泊演化过程中所留下的相关沉积物的影像特征,反演古湖泊在四个不同时期的水域范围,并进一步分析了演化原因以及相应解决对策。研究表明,从更新世晚期至今,湖泊面积缩小了258.2km2。水位下降了76m,其中,在更新世晚期至全新世早期湖泊萎缩速度最快,其间分离出了一些小湖泊,此后湖泊退缩较慢。
Schistosomiasis is a serious public health problem in the middle-lower Yangtze River Basin in China. Study of spatial variation of snail distribution that is related to microgeographic factors can help to choose pertinent measures for snail ...
利用DEM生成等高线模拟静态水平面的方法,模拟水库和地震造成的堰塞湖水淹没模型,叠置二维和三维地理信息数据进行GIS综合分析,用于分析评估淹没损失、预测淹没区域及应急指挥调度。
建立了包含青海湖水下地形的流域DEM(LBD);利用LBD和各时期水位数据,计算湖泊面积和水量;利用LBD和遥感影像,通过三维可视化技术,最终实现一万多年来湖面时空变化的动态模拟。结果表明,青海湖东西两岸的退缩幅度明显大于南北两岸,水位降低对于青海湖湖岸形态有很大的影响;利用恢复水下地形来进行水量计算,简单易行。
The lake level history, here based on the relative abundance of Ca (gypsum), is used for tracing past hydrological conditions in Central Asia. Lake level was close to a minimum before approximately a.d. 300, at abo ...
The mountain yellow-legged frog (Rana muscosa) was once a common inhabitant of the Sierra Nevada (California, USA), but has declined precipitously during the past century due in part to the introduction of nonnative fish into nat ...
Sr isotope and Ca/Mg/Sr chemical compositions of freshwater ostracode tests separated from a sediment core represent the last 16 ka of sedimentation in Lake Constance, Central Europe. The chemical evolution of the paleowater's dissolved load of ...
Mercury contamination in fish is a serious public health concern that contrasts with other health benefits of eating fish. Like most US states, Illinois has monitored fish mercury contamination for decades to warn the public of mercury exposure risks ...
Sediment traps were deployed in the three major basins of Lake Erie, and the central (Mississauga) basin of Lake Ontario, and refurbished seasonally over the period 2000–2002. In Lake Ontario, sediment down-flux rates and correspon ...