三峡水库的运行显著改变了河流原有的水动力条件,引起江心洲形态冲淤调整。为进一步探究三峡水库蓄水对江心洲形态调整的影响,选取库区5个典型江心洲为研究对象,采用Landsat遥感影像以及三峡水库2003—2017年实测的地形和水沙资料,定量分析了不同阶段江心洲的形态调整及时空演变特征。研究表明:伴随三峡库区水位波动,江心洲出露面积逐渐减少,河床呈现累计淤积态势,加快了江心洲的冲淤变化,其中156 m蓄水高程(2006年10月—2008年10月)的淤积强度最大,而2012年后淤积显著变缓;在空间尺度上,距离大坝越远,江心洲淤积强度越小,变动回水区江心洲因受采砂影响,河床局部地形出现不规则变化;同时,受三峡回水影响,江心洲发育模式改变,洲尾顺水流朝下游发育淤长,洲头受清水冲刷垮塌。

为探讨植被根系对河岸冲刷过程的影响作用,取新疆塔里木河岸坡原状土,选取当地优势灌木红柳、乔木胡杨根系,通过室内水槽试验,分析不同植被根系对河岸冲刷起防护作用的贡献率。结果表明:①无根系河岸水下淘刷形式主要为圆弧状,下部抗冲能力差;有根系河岸的淘刷形式主要为三角形,下部抗冲能力强,上部悬空层的稳定性好。②根系的网络固土作用使河岸的抗冲能力提高12%~42%;相同植被根系河岸,根系的布置方式对河岸的固土能力有显著差异,V型根系的固土作用优于竖直型;不同植被根系河岸,红柳根系的固土能力大于胡杨根系,平均提高27%。③根土胶结崩塌体堆积形式主要为三角形,且堆积体的占比大于无根系崩塌体;红柳根系胶结崩塌体的分解速率最慢;根系牵拉系数可作为反应根系对河床防护作用贡献的参数,实际计算中可按1.15~2.52进行估算。研究结果可为塔里木河河道岸坡防护提供理论参考。

In the purpose of exploring the effect of vegetation roots on riverbank erosion process, the contribution rate of different vegetation roots to riverbank erosion protection was examined via indoor flume experiments. The undisturbed soil samples were taken from the banks of the Tarim River in Xinjiang, and the roots of local dominant shrubs <i>Tamarix ramosissima</i> and <i>Populus arbores</i> were selected as research objects. Results demonstrated that: (1) Rootless river bank mainly suffered from arc-shaped erosion with insufficient anti-scouring ability in the lower part, while rooted river bank mainly saw triangular erosion with strong anti-scouring ability in the lower part and good stability in the upper suspended layer. (2) The soil-fixing effect of the root system enhanced the impact resistance of river bank by 12%-42%. Given the root system of the same vegetation, the soil-fixing ability of the river bank differed remarkably with the arrangement of the root system: V-shaped root system had a superior soil-fixing effect than vertical system.<i> Tamarix ramosissima</i> root system had a better soil-fixing ability than <i>Populus euphratica</i> by 27% on average. (3) Root-soil cemented collapse body accumulated mainly in a triangular shape, and the proportion of accumulation is larger than that of non-rooted collapse; <i>Tamarix ramosissima</i> root cement collapse decomposed in a smallest rate. In addition, the root traction coefficient can be used to reflect the contribution of roots to riverbed protection, and can be estimated as 1.15~2.52 in calculation. The research findings offer theoretical basis for the slope protection of the Tarim River.

基于2010—2019年的MODIS卫星影像数据与实地调查,在地理信息技术的支持下,从宏观角度实现了塔里木河流域土壤湿度的遥感监测。研究结果表明,MODIS第7波段的反射率与土壤湿度呈负相关,塔里木河流域上、中、下游土壤湿度在年内空间上、时间上差异较大:通过同期不同河段的对比分析可知,塔里木河流域土壤湿度上游&gt;中游&gt;下游;同河段不同时期对比分析可知,塔里木河土壤湿度增加量表现为上游&gt;中游&gt;下游;塔里木河流域土壤(0~10 cm)湿度年内季节性变化较大,在2019年6月达到最大土壤湿度,约为6.29%,全年最低土壤湿度出现在2月份,仅为4.16%左右;近10 a来,每年2月份土壤湿度的数据变化较大, C_V均超过15%,下游的土壤湿度数据变化较大,C_V均超过15%。研究成果为探明该区域生态气候、土壤湿度提供了依据。

Based on the MODIS satellite image data and field survey from 2010 to 2019, we accomplished the remotely-sensed monitoring of soil moisture in the main stream of Tarim River from a macroscopic perspective with the support of geographic information technology. Results revealed that the reflectance of MODIS band 7 was negatively correlated with soil moisture. Soil moisture in the upper, middle and lower reaches of the main stream of Tarim River varied greatly in space and time during the year. By comparing different river reaches in the same time period, we found that the soil moisture in the upper reaches of Tarim River was higher than that in the middle reaches and that in the lower reaches in sequence. Meanwhile, by comparing different time periods of the same reach, we discovered that the increment of soil moisture in the upper reaches was larger than that in the middle reaches and lower reaches in sequence. Moisture of soil (0-10 cm) in the main stream of Tarim River varied markedly among seasons. In 2019, the maximum soil moisture (6.29%) occurred in June, while the lowest (around 4.16%) in February. In the past decade, each February and lower reaches witnessed the biggest changes in soil moisture data, with the <i>C</i>_V both exceeding 15%.

造床流量是反映河床冲淤的表征指标,也是河道整治的主要参数。基于1960—2019年实测数据,运用改进马卡维耶夫法、平滩水位法、地貌功法,计算并分析了石嘴山、巴彦高勒、三湖河口、头道拐水文站造床流量。结果表明:时间上,1960—1989年、2010—2019年造床流量为2 100～3 540 m³/s,中水河槽冲刷,1990—2009年造床流量为740～1 300 m³/s,河槽淤积萎缩严重;空间上,造床流量呈现上站大于下站的特点;造床流量受来水量影响较大,在汛期水量低于105亿m³的情况下,可以通过刘家峡、龙羊峡、海勃湾水库三库联调适当增大汛期来水量,强化黄河内蒙古段造床作用。研究结果显示改进马卡维耶夫法物理意义明确,计算结果相对合理,可为冲积性河流造床流量确定及黄河内蒙古段河道治理提供参考。

塔里木盆地是亚洲大陆腹地独特的巨型地质地貌单元，是研究新生代地球系统的天然实验室。新生代以来，它经历了古近纪海湾、新近纪湖泊&mdash;三角洲平原、河流&mdash;湖泊&mdash;沙漠、沙漠&mdash;河流的地质演化过程，古地理格局变化的主要因素是远程碰撞造山作用，造成盆地的封闭、气候干旱。古近纪以来，海湾盆地西低东高，构造挤压造成周缘山脉隆升和盆地逐渐封闭，这是盆地演化最主要的动力因素。新近纪南高北低，随着青藏高原隆升，周围山脉持续隆升，早先形成的河湖等地质地貌单元不断被周边山脉所封闭，形成塔里木盆地，发育大湖泊。第四纪以来，盆地西高东低，经历了最快速的地球系统演化，形成中国较大的内流水系以及最大沙漠。内、外动力的耦合作用及其相互作用，控制了塔里木盆地新生代地球系统演化，塔里木盆地周缘新构造活跃，在巨型盆地内发育了河流、湖泊、沙漠、戈壁、雅丹、干盐湖等多种第四纪的地貌类型。不同地质因素时空上相互作用，塑造着巨型盆地地球系统演化，塔里木盆地展示了极干旱地区地球系统第四纪快速的演化过程。

The Tarim Basin is a unique giant geological and geomorphic unit in the hinterland of the Asian continent. It is a natural<br>laboratory for studying the new generation of the Earth system. Since the Cenozoic, it has experienced the geological evolution, such as<br>Paleogene Gulf, the Neogene lake-delta plain, the river-lake-desert, and the desert-river. The main factor affecting the change of<br>paleogeographical pattern is the long-range collisional orogeny, resulting in the closure of the basin and the onset of arid climate. Since<br>the Paleogene, the Gulf Basin has been low in the west and high in the east. The tectonic compression caused the uplift of the<br>surrounding mountains and the gradual closure of the basin, which is the most important driving factor for the basin evolution. During<br>the Neogene, it was high in the south and low in the north. With the uplift of the Qinghai-Tibet Plateau, the surrounding mountains<br>continued to rise, and the geological structure was constantly closed by the surrounding mountains, forming the Tarim Basin and<br>developing large lakes. Since the Quaternary, the basin has been high in the west and low in the east, and has experienced the fastest<br>evolution of the Earth system, forming China's largest inland water system and the largest desert. The coupling and interaction of<br>internal and external dynamics control the evolution of the Cenozoic Earth system in the Tarim Basin. The new tectonic structures in<br>the Tarim Basin are active. In the giant basin, rivers, lakes, deserts, Gobi, Yadan, dry salt lakes, etc. Different geological factors<br>interact in space and time, shaping the evolution of the Earth system in the giant basin. The geological history of the Tarim Basin<br>demonstrates the rapid evolution of the Quaternary Earth system in the extremely arid regions.