石羊河流域历史时期山区地表水资源时空分布特征的树轮记录研究

In the past few years, many serious ecological problems caused by the shortage of water resources have emerged in the Shiyang River Basin. Shortage and irrational utilization of water resources severely restricts its sustainable development. How to solve water and eco-environment problems has been one of the most popular problems which is widely concerned and focused by academic circles. Additionally, to better understand the dynamic distribution and evolution patterns of the Shiyang drainage basin, it is important to identify the relationships between the water resources and climatic variations on a long time scale, because it can enable the recent observed changes to be viewed from a long-term perspective. But hydrologic observation data are short and clearly insufficient for understanding the extreme changes, and how hydrological variability may be changing in a warming world is worthwhile studying. Compared with most of palaeoclimatological proxies, tree-ring shows advantages in its relative high-resolution and annual time-series for calibrating the relationships between climate and proxy, and it has been well established as records of past climate and runoff changes. The upstream of the Shiyang River is chosen as the focuses of this study. A comprehensive study on hydrologic changing history of the study area is conducted, using the multi-disciplinary theory and method, such as natural geography, hydrology, ecology, RS, GIS and so on. Objectives of this study are as follows: (1) Tree-ring width chronologies, gray chronologies at each sampling sites are developed, establishing tree-ring chronology networks of study area. (2) Calculate the surface water resource value based on DEM data, GIS and mathematical models. (3) Reconstruct past changes of surface water resources (SWR) utilizing principal components extraction and stepwise regression, analyze its characteristic, discuss the linkages between SWR series with other runoff, drought series in adjacent areas and SST, PDO, AO indexes, explorer the mechanism of SWR change. We try to draw the runoff depth isograms of different abundant and deficient runoff periods, discuss the character of spatial distribution of runoff depth during historical period. This study provides scientific basis for the optimal allocation, rational utilization and evaluation of water resources, and it is significant in theoretical and practical fields.

石羊河流域人地关系的不协调程度正在加剧，水资源已成为制约该流域经济社会发展的关键影响因素，如何解决水资源及其引发的生态环境问题是当前学术界关注的重点问题之一。本项目以石羊河流域山区为研究区，以地表水资源重建为主线，基于多种树轮指标的树木年轮场、地表水资源计算、不同时期径流深度等值线绘制以及多种数学模型，再结合RS、GIS分析方法，对该区过去高分辨率的水文演变过程进行多学科交叉研究，进而揭示研究区地表水资源历史变化规律、多时间尺度变化特征以及历史时期径流丰枯期的空间分布特征；进一步综合邻近地区的气候、水文序列及太平洋海温、PDO指数等资料，探讨该区地表水资源在更大尺度上的变化规律及驱动机制。该研究为水文、水资源学研究提供新的研究视角和技术方法，并且为水资源优化配置、区域生态环境规划、水资源发展趋势预报等提供了科学依据，具有重要的理论和实践意义。

石羊河流域人地关系的不协调程度正在加剧，水资源已成为制约该流域经济社会发展的关键影响因素，如何解决水资源及其引发的生态环境问题是当前学术界关注的重点问题之一。本项目以石羊河流域山区为研究区，以地表水资源重建为主线，对该区过去高分辨率的水文演变过程进行多学科交叉研究，进而揭示研究区地表水资源历史变化规律、多时间尺度变化特征以及历史时期径流丰枯期的空间分布特征。.研究表明：①上游降水与地表径流的高凝聚性正相关更显著，降水对上游径流的形成起主导作用，人类活动与气候要素共同影响着下游夏季径流的短周期振荡。②各时间尺度SPEI与太阳黑子数在整个研究期内具有极显著的8-12年主共振周期；较长时间尺度SPEI与NAO和PDO在准10年共振周期上显著相关（1970s-1990s）；而ENSO（El Nino-Southern Oscillation）对SPEI的影响主要表现在短时间尺度的高频段上。③影响春季径流形成和丰枯变化的关键区域在河西走廊中东部；影响秋季径流的关键区域在青藏高原的东北缘和河西走廊东部，核心区在100°-105°E，33°-41°N；影响夏季和年径流的关键区域在东亚夏季风北边缘，核心区在100°-110°E，33°-42°N，呈东北－西南走向。④对比青藏高原东北部和东部的多条冬温序列，在过去251a冬温变化的年代际趋向性一致。但小冰期后期和20世纪后期的升温过程，高原区的启动时间早于高原边缘区，呈现由高原区向边缘区推移的趋势，同时高原区的升温速率小于边缘区。⑤在1954年以前西部地区的5条干旱序列具有一致的变化，但在1954年以后其呈现相反的趋势；在季风边缘区的14个干旱序列，过去251a其长期变化一致，显示出在季风边缘区具有相似的大尺度水分背景。⑥过去190a上游山区流量场呈现稳定的同步变化以及中部与东西部流域、东部与西部流域间的差异性。.该研究为水文、水资源学研究提供新的研究视角和技术方法，并且为水资源优化配置、区域生态环境规划、水资源发展趋势预报等提供了科学依据，具有重要的理论和实践意义。

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