【作者】 连英立；

【导师】 张光辉； 聂振龙；

【作者基本信息】 中国地质科学院 ， 地质工程， 2011， 博士

【摘要】 本文以西北内陆黑河流域的张掖盆地地下水对气候变化响应特征与机制为主题,以流域水循环理论为指导,应用水文地质学、地统计学和灰色数学专业理论方法以及MapGIS空间分析等技术手段,采用定性判断和定量分析相结合方法,首先,对上游补给水来源祁连山区和地下水赋存地平原区的大气降水、气温、出山径流、地下水位和地下水温度等关键要素多年监测资料进行系统分析和有机相关耦合,包括全面深入踏勘和了解研究区气候、水文、地形地貌、区域地质构造、地层岩性、地下水埋藏条件和水资源开发利用状况,梳理和识别影响研究区地下水变化主要因素及其年内、年际和年代变化规律；然后,量化解析了上游祁连山区气候变化对张掖盆地地下水补给源结构和补给水量变化影响特征,以及识别了人类活动对张掖盆地水循环过程影响的年际和年内变化特征；最后,探讨了张掖盆地地下水变化对气候变化响应非均一性特征和机制。据此,提出了不同气候条件下张掖盆地地下水合理利用与涵养对策。主要成果与创新性认识如下：(1)近30a来研究区气候由冷干向暖湿转变,祁连山区降水量是影响出山径流量和张掖盆地地下水补给量的主要影响因子研究区多年平均气温分别为-0.95℃(祁连山区)和7.59℃(张掖盆地),降水量分别为408.67mm/a(祁连山区)和118.12 mm/a(张掖盆地),气温和降水量的年际波动变化幅度较大,与区域气候变化密切相关。研究区气温呈波动上升趋势,自20世纪60年代至今祁连山区气温累计上升1.48℃,张掖盆地气温累计上升1.33℃,其中4月份和10月份气温升高对年均气温升高贡献率最大,90年代之后研究区气温升高速率明显增加。自20世纪90年代开始祁连山区降水量显著增加,由1991年的311.85 mm/a增加至2009年的502.60 mm/a,平均增速为10.60 mm/a,其中7、8月份降水量增加对全年降水量增加的贡献率最大。由于张掖盆地为干旱区,年降水量不足150 mm,所以,近年来祁连山区降水量增大是张掖盆地地下水位有所恢复的主要原因。出山径流量与祁连山区年降水量显著相关,其双侧皮尔逊相关系数达0.845,并且达到了0.01置信度的显著性水平。而出山径流量与祁连山区气温关联性不大,其双侧皮尔逊相关系数仅为0.306,置信度显著性水平为0.05。这表明,祁连山区降水量是出山径流量变化的主要影响因子。由于出山地表径流是张掖盆地地下水的主要补给源,且出山地表径流量占总补给量的80%以上,因此,根据祁连山区降水量与出山径流的线性回归模型,若不考虑气温和人类活动影响,当祁连山区降水量大于125 mm/a时,每增加10mm/a,出山径流量增加0.40×108m3/a,地下水补给量增加0.34×108m3/a。(2)张掖盆地地下水对祁连山区气候变化的响应具有滞后延续性在时间上,张掖盆地潜水温度最大值的出现,分别滞后于祁连山区和张掖盆地气温、降水最大值2个月；承压水温度最大值,分别滞后于祁连山区和张掖盆地的气温、降水最大值3个月。祁连山区气候变化对张掖盆地地下水温度的影响,具有明显的滞后延续性。在极端干旱、或者极端降水条件下,它们对张掖盆地地下水温度的影响可持续2-3a,承压水温度对祁连山区气候变化响应的滞后延续性更为明显。(3)张掖盆地地下水对气候变化和人类活动响应在空间分布上具有非均一性1984～2009年期间张掖盆地潜水位和承压水头均呈现不同程度下降过程,其中承压水头下降幅度大于潜水位,在空间上地下水位变幅差异较大。距离河道越远,降幅越大：距离河道越近,降幅越小。反之,距离河道越近,上升速度越快;距离河道越远,上升速度越慢。在张掖盆地东南部倾斜平原,由于远离河道带,地下水位降幅最大；在黑河干流带,地下水位降幅较小。张掖盆地的地下水埋藏条件、地形地貌和地表径流条件是地下水位对气候变化响具有非均一性特征的基础,气候变化和人类活动是动因。河渠入渗量减少和水库的大量修建,造成了张掖盆地东南部山前倾斜平原地下水位连续下降。黑河调水方案实施和近年来祁连山区降水量增大,使得黑河干流径流量和河道渗漏量增加,是张掖盆地南部沿河道带地下水位上升的源泉。(4)遵循祁连山区气候周期性变化规律,有针对性适时调控地下水开发利用强度,有利于地下水环境涵养和水资源可持续利用张掖盆地地下水主要依赖祁连山区出山径流水量补给,因此,应遵循祁连山区气候周期性变化规律,针对张掖盆地不同分区地下水埋藏和补给条件,适时调整地下水开发利用强度,合理涵养地下水,开源与节流并举。重视山前戈壁带地下储水空间的调蓄能力,在丰水期强化人工增加地下水补给调蓄,加强浅埋地带地下水开采,袭夺潜水无效蒸发,防降土壤盐渍化。更多还原

【Abstract】 Based on hydrological cycle theory, this thesis is themed with variation characteristics and mechanism of groundwater response to climate change in Zhangye Basin. Using hydrogeology, geostatistics, and gray theory of mathematics methods and spatial analysis techniques of MapGIS, and combining qualitative judgments and quantitative analysis together, firstly, systematic analyzing and coupling the years of monitoring data of key elements like precipitation, temperature, runoff, groundwater table and temperature which comes from upstream of Qilian Mountains areas and plain areas, including site visit and overall thorough research of climate, hydrology, topography, regional geological structure, formation lithology, groundwater embedment features and water resources development in study area, and identifying the main factors that affect the groundwater change in Zhangye Basin and its intra-annual and inter-annual variation. Then, quantitative analyzed the impact characteristics that how the climate change in upstream of Qilian Mountains impact the groundwater recharge source structure and recharge amount in Zhangye Basin. Also identified the characteristic of intra-annual and inter-annual variation of water cycle process that affected by human activities in Zhangye Basin. Finally, the non-uniformity characteristic and mechanism that the groundwater of Zhangye Basin responded to the climate change were discussed. According to the discussion results, rational utilization and conservation measures of groundwater in Zhangye Basin under different climate conditions were proposed.Main achievements and creative cognitions as follows:(1)The climate of study area is transforming from cold-dry to warm-wet, and the precipitation of Qilian Mountain area is the main infection factors of mountainous runoff and the groundwater recharge of Zhangye Basin.The multi-year average temperature are -0.95℃(Qilian Mountain area) and 7.59℃(Zhangye Basin) respectively. The multi-year average precipitations are 408.67 mm/a (Qilian Mountain area) and 118.12 mm/a (Zhangye Basin) respectively. Annual temperature and precipitation fluctuated greatly, and regional climate change is closely related with it. There is a wavelike rises trend of temperature in study area. Since 1960s, the temperature of Qilian Mountain area has risen 1.48℃and the temperature of Zhangye Basin has risen 1.33℃. Temperature increase on April and October are the largest contribution rate of annual temperature increase in those areas. Since 1990s, the temperature rising rate is significantly increased. Since 1990s, it has a significant increase in precipitation of Qilian Mountain area. The precipitation of Qilian Mountain area has increased from 311.85 mm/a (1991) to 502.60 mm/a (2009), and the average increase rate is 10.60 mm/a. Precipitation increase on July and August are the largest contribution rate of annual precipitation increase. As the annual precipitation is less than 150 mm in arid Zhangye Basin, so the reason of its groundwater table rising is the increase of precipitation in Qilian Mountain area.The mountainous runoff is significantly correlated with precipitation of Qilian Mountain area, and its bilateral Pearson correlation coefficient is up to 0.845 with significance of the 0.01 confidence level. The mountainous runoff is not significantly correlated with the temperature of Qilian Mountain area, and its bilateral Pearson correlation coefficient is just about 0.306 with significance of the 0.05 confidence level. It shows that, the precipitation of Qilian Mountain area is the main influencing factors of mountainous runoff. Because the mountainous runoff is the main recharge source of the groundwater of Zhangye Basin and the mountainous runoff accounting for more than 80% of the total recharge, so, according to the linear regression model between precipitation of Qilian Mountain and mountainous runoff, if didn’t consider the temperature and human activities impact, when the precipitation of Qilian Mountain is greater than 125 mm/a and increase 10 mm/a, the mountainous runoff increase 0.40×108m3/a, and the groundwater recharge increase 0.34×108m3/a.(2) The groundwater of Zhangye Basin response to climate change of Qilian Mountain area has a lag-continuity characteristic.The maximum shallow groundwater temperature is lagging behind the temperature and precipitation (both in Qilian Mountain area and Zhangye Basin) for 2 months, and the maximum confined groundwater temperature is lagging behind for 3 months. The climate of Qilian Mountain area has a significant influence on groundwater of Zhangye Basin with a lag-continuity characteristic. Under the condition of extreme drought and extreme wet, its affection on groundwater of Zhangye Basin can last for 2-3 years, and the confined groundwater of Zhangye Basin has a more obvious response to climate change of Qilian Mountain area(3) The groundwater of Zhangye Basin response to climate change and human activities has non-uniformity characteristic.During the year 1984 to 2009, the shallow groundwater table and confined groundwater head had declined in different degrees. The decrease amplitude of confined groundwater head was more than shallow groundwater table, and there was a great difference of groundwater table change amplitude in space. Farther from the river, greater of the groundwater table decline; closer to the river, smaller of the groundwater table decline. Conversely, closer to the river, greater of the groundwater table rising; farther from the river, smaller of the groundwater table rising. Because far from the river belt, the southeast clinoplain of Zhangye Basin has a maximum groundwater table decline. Near the Heihe mainstream area, the groundwater table decline smaller.The groundwater buried condition of Zhangye Basin, topography and geomorphology and surface runoff condition are the basis of non-uniformity characteristic that the groundwater responses to the climate change, and the climate change and human activities are the motivations. The decrease of river water infiltration and the construction of reservoirs lead to the continuously decrease of groundwater table of the southeast clinoplain of Zhangye Basin. The implementation of Heihe water transfer project and the increasing of precipitation of Qilian Mountain area in recent years lead to increase of river water infiltration which was the main reason of groundwater table rising at the southeast clinoplain of Zhangye Basin.(4) Following the periodic variation law of climate change in Qilian Mountain area, target and timely regulate the groundwater exploitation intensity are beneficial to groundwater conservation and sustainable use of water resources.The mountainous runoff of Qilian Mountain area is the main recharge source of groundwater of Zhangye Basin, so it should follow the laws of climate periodic variation regularity and based on different partitions groundwater buried conditions and recharge conditions, adjust intensity of groundwater exploitation timely and conserve groundwater reasonably. Broaden the sources of income and reduce expenditure simultaneously. Pay attention to the regulation and storage capacity of the Gobi zone of piedmont, increasing groundwater recharge storage in the wet season artificially and strengthening groundwater exploitation in shallow-buried zones in order to capture shallow groundwater invalid evaporation and prevent soil salinization.更多还原