Ganjiang River Research Articles

Impact of Climate change on the Runoffs from Hanjiang River and Ganjiang River in the Yangtze River Basin

近几年来,国家气候中心己经建立了中国主要四大流域气候对水资源影响评估的模式框架.本文拟进一步证明其中之一的两参数分布式月水量平衡水文模式对长江之上汉江和赣江两子流域径流的模拟能力,结果表明该水文模式对目前气候条件下径流模拟效果较好,运行稳定,可用于实时业务运行.在此基础上,利用ECHAM4和HadCM2两GCM(General Circulation Model)未来气候情景模拟结果及目前实测气候情况,对汉江和赣江两子流域的径流对未来气候变化的敏感性进行评估.经检验,两GCM对未来气候,特别是降水情景模拟存在一定差异,因此,造成径流对气候变化的响应不同,这充分反映了全球模式模拟结果不确定性在气候变化影响研究中的重要性.;During the last few years, a modeling framework on the assessment of climatic impact on water resources for four main basins in China has been established at National Climate Center (NCC) of China. This work aims at demonstrating the capability of one of the hydrological models in simulating observed river flow and in assessing the sensitivity of the runoff to climate changes in two sub-basins of the Yangtze River. The study area includes Hanjiang River and Ganjiang River sub-basins. A distributed water balance model was used to simulate monthly water balance under present day and future climate scenarios. First, a control simulation for the period 1961-2000 using the observed climatic input was performed. A method to grid the station data into a 30 km×30 km grid system is described and tested, which provides the input to the hydrological model. A comparison between the simulated and measured runoff demonstrates capability of the model. A baseline period from 1961-1990 is chosen to represent the current climate. The potential impacts of future climate change are simulated by perturbing the observed driving climate variables (rainfall and temperature) during the baseline period and re-running the model for another two 30-year periods (2021-2050 and 2051-2080) with climate change scenarios estimated by General Circulation Model (GCM). The scenarios were constructed from the output of ECHAM4 and HadCM2 experiments. The experiments assume a 1% per year increase in atmospheric CO2 concentrations from 1990 to 2100. Monthly differences between 2021-2050 and 1961-1990, as well as between 2051-2080 and 1961-1990 were used to force the hydrological model. The results for the two sub-basins were analysed, focusing on the changed runoff. While temperature changes are essentially consistent between the two GCMs, precipitation change shows a relatively large difference, which causes different response of runoff. This underlines the importance of uncertainties associated with GCM.

Comparison of quaternary deposit environment among Lushan, Huangshan and Tianmu mountains

The data of Fe3+/Fe2+ show that the lowest annual air temperature of the Lushan, Huangshan and Tianmu mountains was not below 0°C, therefore, glacier couldn’t develop in these regions. According to palaeomagnetic test combined with the phenomenon of reticulate pattern ground and lithologic identification, the authors elaborate that the “Poyang moraine” is mainly the fluvial sediments of the early period of the Middle Pleistocene. It was formed by transportation of the ancient Ganjiang River under the humid hot climate. For CM image, the Dajiaochang profile of the Lushan Mountain is very similar to periglacial and the debris flow deposits, but the profile of Jiangpochang and Yaoshaling have many kinds of geneses, i.e., debris flow, water debris flow and alluvial etc. In the south piedmont of the Huangshan Mountain, slope gravity and slope seasonal running water transportation are mainly deposit factors. In the “glacial varve” of the Denglongqiao profile of the Tianmu Mountain, its CaO and Na2O content is lower than the nonglacial varve, the fact shows that it has the features of the violent leaching, weathering and nonglacial action.

Historical documents on the origin and evolution of Poyang Lake

本文通过大量史料分析和地质钻孔证据,认为鄱阳湖大水面形成于公元400年前后,为距今约1600年的年青湖泊。鄱阳湖形成的直接和主导因素是长江主泓道南移到湖口一带,因江水阻碍赣江水的下泄,使湖泊水域向南扩张,到唐初面积最大时曾达6000km²。之后,鄱阳湖水位和面积的变化主要取决于湖口处长江水位的变化。;According to the quantitative analysis on historical records and deposit evidences,Poyang Lake, formed in about 400 A.D., can be regarded as a relatively young lake.The direct and main reasons of its formation were due to the shift of the Yangtze River's main cause to the vsouth.As the river obstructed the out-flow of the Ganjiang River, its lake water was extended southwards to form Poyang Lake.The variation of the surface area and water level of Poyang Lake mainly depends on the fluctuation of the Yangtze River at the Hukou section.The evolution of Poyang Lake may undergo the following 4 stages: 1.During the Han Dynasty (206 B.C.-220 A.D.) Water in the northern lake basin used to be a relict part of the ancient lake (the Pengli), and no large water body existed on the ancient Ganjiang River Plain to the south of Yingzikou, where both Xiaoyong City and Haihun City were ever built.2.From the Six Dynasties (222-618 A.D.) to the early stage of the Tang Dynasty (618-718) Water body in the northern lake basin rapidly extended southwards to cover an area of about 6000km² (the highest water level).3.From the last stage of the Tang Dynasty to the Song Dynasty (618-1280A.D.) In the southern basin the lake delta developed rapidly and the lake began to descend.4.From the Ming Dynasty to the Qing Dynasty (1368-1911 A.D) The lake area enlarged again and the Ganjiang River mouth was submerged, as a result many tributaries were formed.

Eco-environment of wintering habitat of migratory birds in poyang lake and prediction of impacts of the theer-gorges project on it

鄱阳湖是我国最大的淡水湖泊。每年秋冬枯水期，在赣江和修水入湖三角洲前缘，由草滩-泥滩-积水洼地组成的湿地生态环境为越冬候鸟提供了良好的栖息条件。调查表明，高程12-13m低地最适宜候鸟越冬生存。三峡建坝后，10月份水库蓄水长江下泄流量减少，引起鄱阳湖的提前退水和滩地提前显露，虽使动物性饵料略有减少，但对食草候鸟影响不大。人类提前对草滩资源利用和利用下限的扩大，使候鸟隐蔽条件变差。;Poyang lake is the largest freshwater lake in China.During the low water level in autumn and winter, ecological environment of wetland in the delta front of the Ganjiang River consists of grass bank, muddy beach and back depression, providing favourable conditions for migratory birds to survive their winter. The investigation shows that the wetland at altiude of 12-13m is the most favourable place for migratory birds7 wintering. However the building of Three-gorges Reservoir may alleviate the discharge of the Changjing River in October, thus, may lead to the falling of the water level and to the exposedness of the lake bcach earlier than expected. The above-mentioned results exert less influence on herbivorous birds, but may reduce the numbers of animal foods slightly, the grass bank resources may be used not only earlier, but alse fully, because of the expanding of the lake beach, but the shelter condictions for migratory birds' wintering may get worse.