河西走廊地区现代沙尘暴演化特征、影响因素与源区界定

The Hexi Corridor located in the key position of the "Silk Road Economic Belt", its sustainable and stable development of society, economy and ecology plays an important role in the implementing strategy of the "Silk Road Economic Belt". The Hexi Corridor area is the most frequent sandstorm occurring area in China or even the whole Asia, where sandstorm is one of the most serious disasters. Therefore, to carry out the research of sandstorm in the area is imminent. Some previous studies on sandstorm were mainly focused on the formation mechanism, variation characteristics, source areas (identified some macroscopic source areas by doing simulations) on macro scale and influences on human healthy, that provide the valuable basic data for our study. In order to weaken the sandstorm influence, the evolution characteristics and the major influencing factors of sandstorm need to be reveal on a smaller scale, and the source areas and their dust material contribution should be find out. By doing these, it could provide theoretical support and effective ways for sandstorm prevention and control. This project proposed to collect modern sandstorm samples in the Hexi Corridor area. By used remote sensing data, the influencing ranges of the sandstorm were recognized and surface soil samples were collected in the different geomorphic units. The proxies' indicators of the samples were used to deduce the dust material contribution of the every potential source area. The sandstorm evolution characteristics as well as the major influencing factors were revealed by analyzing basic data of the modern sandstorm combined with meteorology, NDVI and humanities.

河西走廊地处“丝绸之路经济带”的关键部位，其社会、经济、生态持续稳定发展对目前所实施的“丝绸之路经济带”战略具有重要意义。由于河西走廊是中国乃至整个亚洲沙尘暴发生最频繁的地区，沙尘暴是该地区最严重的灾害之一，因此开展该地区沙尘暴研究迫在眉睫。以往针对沙尘暴的研究主要是在宏观尺度上探讨其形成机理、变化特征、源区（主要是通过模拟识别出一些宏观源区）及其对人体健康的影响，这为我们的研究工作提供了宝贵的基础资料。要削弱沙尘暴所产生的危害需要在更小尺度上揭示其演化特征与主要影响因素，找出各个源区并识别出其沙尘物质贡献率，为今后具体防治工作提供理论支持并指明方向。本项目拟在河西走廊地区采集现代沙尘暴样，利用遥感资料识别出沙尘暴的影响范围并在不同地貌单元采集表土样，通过样品代用指标给出各潜在源区沙尘贡献率。通过对现代沙尘暴基础资料分析揭示其演化特征，结合气象、NDVI以及人文数据，找出其主要影响因素。

河西走廊是中国乃至亚洲沙尘暴发生最频繁的地区之一，尘暴的频发制约了社会经济的持续发展和“丝绸之路经济带”的建设，并对其生态环境造成严重危害。鉴于此，本项目以河西地区为主展开相关研究。项目执行期间，我们在河西地区不同地表单元共采集表土样2064个；于2017-2019年在河西主要城镇布置尘暴采集点24个，共采集尘暴样200余个。在此基础上，利用野外考察、卫星遥感、地面监测等数据，结合数值模拟、统计分析、模型模拟等手段，揭示了河西地区乃至中国北方现代尘暴的演化特征与驱动机制；界定出主要沙尘源并反演沙尘传输轨迹；利用复合指纹识别技术建立沙尘源区样与尘暴样之间的端元模型，进而示踪并量化各源区的贡献。研究结果可为今后防沙治沙工作提供理论与科学数据支撑。.通过研究我们发现：.1. 包括河西走廊在内的中国北方沙尘暴易发生于春季，1960-2007年尘暴频数基本呈现波动下降趋势。空间上，尘暴多发区呈现出以高频区为中心向外辐散的态势，尘暴高发旬从西到东呈现由上旬到下旬过渡的特点。风速、降水、温度、植被是尘暴的主控因子。风速与尘暴在时空尺度上均呈现较好的相关性。其中最大风速与尘暴频率呈显著正相关，是尘暴最重要的驱动力，临界起沙风速是尘暴旬差异的主控因子。.2. 影响河西地区的主要沙尘源包括以古尔班通古特沙漠为主的新疆北部地区(A)、塔克拉玛干沙漠与库姆塔格沙漠及周边地区(B)、柴达木盆地(C)、河西地区及其周边的戈壁沙漠(D)。其中，源区B中大多数沙尘起源于库姆塔格沙漠，源区D对河西地区PM10浓度贡献最大。.3. 复合指纹技术在河西地区沙尘源示踪和源贡献量化方面表现出较好的适用性。总体上自然源贡献大于人为源，但是后者(主要是农业源)对河西地区各城市的贡献基本维持在40%左右。河西地区西部戈壁和农田对区内各城市沙尘的贡献由于距离效应基本呈现由西向东减少的趋势；受盛行西风影响，东部各城市沙尘来源较为广泛。.研究成果主要以科研论文的形式呈现，其中与本项目直接相关的第一标注SCI论文有10篇。