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过去 2000 年新疆北部的湿度变化及其控制机理
No full text新疆北部过去 2000 年的气候变化一直备受相关研究者的关注，因为理解新疆北部过去2000年的气候变化有助于提高我们对大尺度气候-水资源内在关联的认知，也有助于提高我们应对新疆北部未来气候变化的能力。但是，新疆北部过去 2000 年气候变化的已有研究存在分辨率低、测年误差大的缺陷。而且，新疆北部也鲜有关于气候-水资源内在关联以及人类活动对水资源影响的报道。本文通过基于泥炭和湖芯的高分辨率代用指标，揭示了新疆北部过去 2000 年气候-水文变化之间的联系，探讨了最近百年来人类活动对水资源的影响。基于四个序列的资料，我们得出了下列结论：1）位于阿尔泰南部青河县的玉什库勒（YSKL）钻孔泥炭藓（非维管束植物）δ13Ccelluose所指示的土壤湿度表明：在约 170 BC 至 460 AD 期间，δ13Ccelluose所指示的湿度整体较高。在约 460 AD 至 870 AD 期间，湿度比前期（约 170 BC 至 460AD）更高。在约 870 AD 至 1590 AD 期间，湿度出现频繁的波动但整体偏低。在约 1590 AD 至 1830 AD 期间，湿度再次升高。在约 1830 AD 至 2010 AD 期间，泥炭芯的泥炭藓很匮乏，取而代之的是大量的苔草植物。偏正的苔草植物δ13Ccelluose 实际上指示了较低的土壤湿度。过去两千多年阿尔泰南部的暖季湿度变化主要受到降水量变化的影响，暖季温度也参与了湿度的变化过程。YSKL 的资料显示，北大西洋涛动（NAO）主导了 YSKL 的湿度变化过程，即正相的 NAO有利于湿度增加，负相的 NAO 导致了湿度下降。2）我们利用位于阿尔泰南部的黑阳坡（HYP）泥炭芯的纤维素 δ13Ccelluose和泥炭吸光度反演了 HYP 过去 650 年来的水文变化。HYP 泥炭 δ13Ccelluose所指示的地表湿度表明：在过去约 650 年来 HYP 的湿度一直是下降的。其中，在约1360 AD-1725 AD 期间，湿度下降可能是由低温条件下暖季降水下降引起的；在约 1725 AD-2013 AD 期间，湿度下降则可能是由高降水条件下暖季温度上升导致的蒸发增强引起的。泥炭吸光度所指示泥炭腐殖化程度表明：在约 1360 AD 至1725 AD 期间，泥炭的分解是增强的；在约 1725 AD 至 2013 AD 期间，泥炭的分解是减弱的。其原因可能是：在约 1360 AD 至 1725 AD 期间，暖季降水的减少使得地表湿度下降，从而改进了地表土壤层的氧化环境，更有利于有机质的分解，导致吸光度增加。在约 1725 AD 至 2013 AD 期间，随着湿度的继续下降，制约泥炭分解的因素由之前地下水位控制的氧化还原环境变成了地表土壤的可利用水的多寡。HYP 的资料表明该地区的降水在过去 650 年里很可能一直受到大西洋年代际振荡（AMO）的影响。3）我们对位于中天山的大龙池（DLC）湖芯进行了地球化学指标和硅藻组分的分析，并在这些分析的基础上重建了过去约 470 年的水文历史。作为温度代用指标的脆杆藻丰度（即 Fragilaria%）显示：约 1620 AD 至 1700AD 期间的温度接近过去约 470 年的平均值；约 1700AD 至 1825 AD 期间的温度显著偏低，其中约 1690 AD 至 1780 AD 为过去约 470 年以来的最低温度时段；约 1825 AD 至 2013 AD 期间的温度整体偏高并呈增加趋势。DLC 的温度变化很好地响应了北半球的温度变化，而后者是由太阳辐射和大气 CO2 所驱动的。过去约 470 年来，DLC 湖水盐度的变化受降水、温度、冰川融水量的控制。具体地讲，约 1540 AD 至 1570 AD 期间湖水中等水平的盐度是由适中的温度和适量的降水导致的。约 1570 AD 至 1700 AD 期间湖水极高的盐度是由极低的降水量导致的。约 1700 AD 至 1825 AD 年间湖水适中的盐度是由适中的降水和低温导致的低蒸发量共同调控的。约 1825 AD 至 1945 AD 年间极低的湖水盐度是由高温导致的冰川融化引起的。即前一时段（1700 AD 至 1825 AD）在低温条件下的冰川扩展为本时段（1825 AD 至 1945 AD）高温条件下的冰川融化提供了条件。约 1945 AD 至 2013 AD 期间的湖水盐度是由降水和温度二者调控的。较低的湖水盐度不仅是降水增加的结果，也是在高温条件下冰川融化的结果。我们的结论是：过去近 470 年来，天山中部的降水很可能一直受到 AMO 的影响。4）我们对位于新疆北部腹地的艾里克湖（ALK）的湖芯进行了地球化学和硅藻组分的分析，并据此重建了过去约 130 年的水文历史。我们重建的 ALK 湖面积的变化可分成两个主要阶段：自然因子控制阶段（约1884 AD 至 1960 AD）和人类因子控制阶段（约 1960 AD 至 2013 AD）。在自然因子控制阶段，ALK 湖依次出现了低湖面积（约 1884 AD 至 1920 AD）及高湖面积（约 1920 AD 至 1960 AD）的变化。我们推测，自然阶段的 ALK 湖面积很可能与新疆北部的暖季降水有关，而后者很可能受到 AMO 的影响。在人类因子控制阶段，湖面积完全受控于人类活动。由于人类开采地下水以及直接从 ALK上游的白杨河引水，ALK 湖出现了湖面积的逐渐缩小直至干涸（约 1960 AD 至2000 AD），之后通过引额济克人工沟渠调度了额尔齐斯河河水补充到 ALK 湖，湖面积才得到了恢复（2000 AD 至 2013 AD）。5）通过对比新疆北部及其周边地区（下称北疆）、新疆南部及其周边地区（下称南疆）过去 2000 年的湿度变化，我们发现，北疆和南疆的湿度变化具有较好的一致性。我们的比较结果显示，北疆和南疆过去 2000 年的湿度变化呈现如下特征：在约 0 AD 至 700 AD 期间，湿度偏高；在约 700 AD 至 1350 AD 期间，湿度偏低；在约 1350 AD 至 1900 AD 期间，湿度偏高，尤其是在约 1500 AD 至 1750AD 时段，北疆和南疆都进入了稳定的湿润期；在约 1900 AD 至 2000 AD 期间，湿度偏低，但是最近 50 年的湿度却是增加的。总得来说，北疆和南疆的湿度变化与东亚季风区的湿度表呈现了反相关系。6）新疆过去 2000 年来的湿度主要受到 NAO 和 AMO 的影响。其中 NAO可能更多的影响了新疆冬季降水而 AMO 可能更多的影响了北疆夏季降水。NAO通过与西伯利亚高压的交互作用，影响了西风环流中最大水汽传输轴的位置，最终影响到了新疆的冬季降水。正相的 AMO 有利于水汽进入西风系统，能够在北疆上空 1000-400 hPa 的区域形成了一个经向的水汽输送路径，将北太平洋的水汽输送到北疆，能够引起印度季风的强度以及持续时间增加，最终导致北疆地区夏季降水增加
新疆屯垦文化与旅游开发模式研究
No full text屯垦文化是具有高度爱国主义精神、兼收并蓄气度、独一无二的地域文化。鲜明的特征使屯垦文化形成了强大的吸引力，激发了人们的好奇心和旅游动机。作为旅游活动的重要资源，屯垦文化及遗产具有巨大的旅游产业价值。本研究构建的屯垦文化旅游资源分类及评价体系合理、普适，研究结论不仅为屯垦文化旅游资源的研究提供定量研究的方法与思路，也为屯垦文化旅游开发提供了重要的参考依据。主要研究内容如下：1.分析汉晋、隋唐、清代民国及新中国等历史阶段屯垦文化形成、变迁及特征；丰富的聚落、语言、制度等屯垦文化景观使屯垦文化内涵丰富,旅游吸引力大。2.提出了屯垦文化旅游资源分类方案：（1）按照资源性质将屯垦文化旅游资源划分为物质文化类和非物质文化类 2 个主类。（2）根据资源赋存状态与主导要素分为 10 个亚类。（3）按照景观单元及成因确定 56 个基本类型。3.非物质类屯垦文化旅游资源类型结构特征和空间分布特征。（1）非物质文化遗产：类型数量来看，民俗类非遗项目（13 项/26.53%）、传统（手工）技艺类(9 项/18.36%)最多。空间分布方面，集中分布在北疆与东疆地区，其中察布查尔县（14项/28.57%）最多。（2）旅游节庆：类型数量来看，物产餐饮型>自然景观型>民俗风情、娱乐游憩型>综合型>历史文化型>博览会展型、运动休闲型。从空间分布来看，昌吉州数量最多。从时间分布来看，多集中于 6-8 月底，占全年节庆的 42.2%。4.物质类屯垦文化资源类型结构和空间分布特征。（1）历史遗址遗迹类资源涵盖各种类型。其中，古遗址（137 处/68.2%），古建筑(25 处/12.4%)，近现代重要建筑(23 处/11.4%)所占比重较大多。空间分布呈明显的带状、凝聚型分布，主要集中在丝绸之路北道、中道、南道、伊犁河谷 4 条集聚带上。（2）博物馆类：自治区博物馆中综合性博物馆最多（74 家/84.1%），呈现整体分散的空间分布特征。兵团 88 个博物馆集中分布在天山北麓一带、塔城地区、伊犁地区、阿克苏地区、巴州及和田地区，具有“整体分散，局部集中”的空间分布格局。5.运用特尔非法，从屯垦文化价值及旅游资源要素价值、自然社会环境，开发条件 3 个方面构建屯垦文化旅游资源综合评价指标评体系。通过层次分析法分析得出，屯垦历史文化及观赏游憩价值权重值（0.69）最大，是吸引游客的物质基础。以新疆生产建设兵团为例进行实证研究分析得出，目前兵团屯垦文化旅游资源的资源品质特征是“两头小中间大”，即 I 级资源（6 个/15.8%）Ⅲ级资源（2 个/1.6%）。在类型数量结构上，产业休闲类旅游资源>文化场馆类和人文综合类>历史遗址遗迹类。呈现出南北疆的不均衡的空间分布特征。6.从微观、宏观、中观三个尺度提出博物馆、5A 屯垦名城（镇）、遗址公园、特色街区等屯垦文化旅游开发模式。针对非物质文化遗产资源提出遗产研习中心开发模式
聚苯乙烯微粒和蒽的联合作用对斑马鱼的影响
No full text水环境中的微塑料污染不仅破坏生态系统，而且危害水生动物。生物体会误食微塑料，微塑料的粒径是影响生物摄取和累积的主要因素之一。本文使用激光扫描共聚焦显微镜观察20-1000 nm的聚苯乙烯微粒在斑马体内的累积情况，除了摄取，聚苯乙烯微粒还可能是通过肠的渗透作用能进入到鱼体内，这可能是小粒径的塑料进入生物体的另一个途径。并且只研究单一的污染物已经不能够完全了解复杂的污染体系对水生动物的毒害效应，所以，本文选择聚苯乙烯微粒和蒽这两种物质，通过单细胞凝胶电泳技术和超细纤维光纤氧气传感器测量斑马鱼的DNA损伤和氧气的消耗量。同时通过模拟胃肠液的吸附解吸附实验，研究聚苯乙烯微粒和蒽之间的相互作用。微塑料被海洋生物摄入后，会沿着食物链向上传递，最终可能会对人类的健康造成潜在危害。本文研究聚苯乙烯微粒在无蒽和有蒽两种情况下，从团藻到斑马鱼的营养转移。本研究的主要结论如下：（1）20、50、200、500、1000 nm的聚苯乙烯微粒，均能在斑马鱼肠道累积；而只有20和50 nm的聚苯乙烯微粒，能在斑马鱼鳃和鱼肉组织中累积。同时发现20和50 nm的聚苯乙烯微粒能渗透鱼肠黏液，这可能是小粒径的塑料进入生物体组织的另一个途径。（2）在20-1000 nm的范围内，聚苯乙烯微粒对斑马鱼几乎没有毒害性，但蒽能严重损伤斑马鱼的腮细胞，聚苯乙烯微粒和蒽同时胁迫斑马鱼时，聚苯乙烯微粒阻碍了蒽的毒性。通过测量鱼的呼吸频率也证实了这一结果。这可能是因为聚苯乙烯微粒和蒽发生了吸附作用，减少了蒽接触生物体的几率，研究发现聚苯乙烯微粒和蒽的吸附反应能自发进行，但在含有高浓度胆汁盐的肠液中，蒽能从聚苯乙烯微粒上解吸附下来。（3）在没有蒽的情况下，20 nm的聚苯乙烯微粒更容易并且更多的附着在活的团藻上，因此被斑马鱼摄入团藻后，小粒径的聚苯乙烯微粒更容易进入斑马鱼体内。而在含有蒽的情况下，发现低浓度的蒽促进团藻生长，而高浓度的蒽则抑制团藻的生长状态，以及200 nm的聚苯乙烯微粒更容易附着在已死亡的团藻上，更易被斑马鱼摄入，在鱼肠内和食物累积在一起。总之，20和200 nm的聚苯乙烯微粒都能从活的或者死亡的团藻上传递到斑马鱼体内，并且经过团藻传递后，聚苯乙烯微粒和蒽的联合作用对斑马鱼的毒性降低
基于 GIS 的无人机地理视频三维可视化
No full text地理视频（GeoVideo）是集成视频数据与空间数据进行地理信息表达的新方法，近20年来，国内外学者在视频GIS领域进行了相关研究。已有研究所表达的地理视频空间信息直观性差，不利于视频影像判读。此外，已有研究成果大多采用地面采集设备获取视频数据，而利用无人机获取资料的研究较少，其中关于无人机视频与三维GIS集成的相关研究更是少有报道。无人机遥感具有机动灵活、成本低、时效性强等优势，已成为获取地面数据的重要手段。提出适用于三维GIS的无人机地理视频数据模型，将无人机遥感获取的视频信息与三维GIS集成，实现无人机视频在三维场景中的动态渲染，不仅能发挥无人机自身优势，还可以充分利用三维GIS提供的空间信息快速判读无人机视频中丰富的影像信息。本文在回顾国内外学者对视频 GIS 相关研究的基础上，总结目前研究中存在的问题及发展趋势，提出了无人机地理视频数据模型的描述方法，将其抽象为视频数据、空间数据和元数据。其中元数据和空间数据分别采用 XML 文件和 CSV 文本文件存储。在此基础上开发三维无人机视频 GIS 系统，改进了许多传统视频 GIS 系统的缺陷，拓宽了地理视频的应用领域。本文的研究思路是：（1）提出无人机地理视频数据模型的描述方法，即设计无人机视频和空间数据的物理存储方法；（2）基于 MFC 和OSG 图形引擎开发三维 GIS，通过 Esri CityEngine 创建主要的三维模型，并采用VirtualPlanetBuilder（VPB）构建数字地形影像；（3）将无人机视频动态渲染到三维场景，按照真实的飞控记录模拟无人机航拍过程，计算航摄仪拍摄范围，将视频帧以纹理映射的方式显示到此范围内；（4）提出无人机地理视频数据的定量评价方法，通过测试视频帧在不同位置的定位误差，对无人机地理视频数据的精度进行定量评价。通过对本文设计的三维无人机视频 GIS 进行系统测试，结果表明：（1）本文提出的无人机地理视频数据与三维 GIS 的集成方法是可行的，且技术实现比较简单；（2）无人机的飞行模拟能够反映真实航拍过程；（3）针对二维纹理映射和三维纹理映射设计的两种视频显示模式，两种方法优势互补，可以根据实际环境进行切换；（4）视频帧显示的空间信息与对应的地理实体位置非常接近，能够反映真实地理空间信息
艾比湖流域沉积物元素地球化学特征及其揭示的环境信
No full textSoil is an important basis material for the survival of plants and animals on the earth. It is also an important resource for the development of human production. Element as an important component of soil, its natural content depends on the natural factors such as parent material, soil formation, topography, regional climate, biology and other natural factors. Lake sediments are faithful records of the natural environment evolution (climate, hydrology) and information of human activities in different periods. The elements in the soil of the river basin are imported into the lake under the action of erosion and transportation, and are deposited on the bottom of the lake. The changes in the records of its material sources, the degree of geochemical weathering and erosion, the intensity of human activities, regional climate change and the history of lake geochemical evolution are important indicators of regional environmental change. Therefore, in this study, physicochemical proxies (focus on elements) of sediment core in Ebinur Lake are studied, statistical analysis, the semi-variance function model, IDW method and potential ecological risk index method are using to analyze the elements spatial heterogeneity and influence factors of elements in topsoil are also analyzed; using enrichment factor correction method, sequential clustering analysis method to analyze the geochemical characteristics and the environment evolution history, heavy metal pollution history of watershed are also analyzed. This study, in order to give basic scientific guides for the coordinated development of the regional ecological environment and human society, a basic information of the regional environmental change and its response to human activities in Ebinur Lake basin. The main conclusions are listed as follows: （1） Descriptive statistics of element concentrations in topsoil showed: The average contents of Ba, Mn, V, Pb, Cr, Co, Ni, Cu in the topsoil of Ebinur Lake were lower than those of Xinjiang soil background value, while other elements of the average value are higher. The spatial distribution of the contents of elements Ca, Mg, Na, Sr, Ni and Cd shows the most obvious difference from medium to strong variability, while the other elements shows weak variability. The high value area of most elements is mainly located in the fields of farmland, traffic trunk, river and urban residential areas, which indicates that the distribution of surface elements in the study area is affected by human activities and local environment. （2） The environmental proxies of particle size, total organic carbon and elementsin Ebinur Lake shows that there are two obvious differences at the deep of 23cm (1960 AD): the content of each environmental proxy was lower and changed small before 1960; after 1960, the content suddenly increased and fluctuated significantly, especially heavy metals Co, Cr, Cu, Ni, Pb, V, Zn and so on. （3） The influence factors of elements in topsoil were analyzed by classical statistical and geostatistics analysis, which shows that elements Al, Fe, K, Ti, Ba, Be, Mn, V, Ti, Ba and so on have a medium to strong spatial autocorrelation and the spatial structure of the element P and the heavy metal elements Zn, Pb, Ni and Cu are more complicated due to random factors such as tillage fertilization, transportation, industrial and agricultural production. Elements Ca、Sr、Mg have a strong active geochemical characteristic, in addition to under the influence of regional soil parent material, and easily influenced by local factors lead to complicated spatial structure. Cd is a heavy metal element, however, it is divided into the same class with Ca, Sr and other activity chemical elements, which may be affected by the man-made industrial and agricultural activities, traffic and other anthropogenic resulting in large differences of the distribution and strong spatial variability in the study area, then there is no spatial autocorrelation at the sampling scale. Element Na shows a poor spatial structure due to the regional natural environment changes and the impact of man-made farming. （4） Elements in sediment core are divided into three assemblage: Fe, Mn, V, Ni, Li, Cr, K, Al, Co, P, Ti, Be, Pb, Cu, Ba and Zn are mainly derived from watershed terrestrial debris, and the content of those elements are mainly affected by the watershed erosion intensity. Among them, the changes of heavy metals Co, Cr, Cu, Ni, Pb, V, Zn and nutrient P were nearly different in the past 150 years. The ordered specimen cluster analysis method was applied to study the lake environmental changes base on the enrichment factors of heavy metals and P. The results show that the environmental evolution history nearly 150 years can divide into two distinct stages taking 23 cm (1960) as the boundary in the Ebinur Lake basin:Stage I. From 1875 to 1960 AD, at this stage the level of social development of the basin is low, human activities lead to less input of heavy metals, the basin environment is mainly affected by regional natural changes; Stage II. From 1960 ~ Present, with the increase of population, economic development, industrial and agricultural activities increased, especially agricultural water consumption increased, most of the heavy metal elements and P relative to the early have a more obvious increase. The second type of elements includes Mg and Na, mainly from the evaporation of salt crystals in lake water. Due to the development of oasis agriculture and the increase of irrigation water, the lake water level fluctuates violently under the influence of climate change and human activities which lead to the fluctuations Mg, Na and other elements. The third class elements include Ca and Sr, which are controlled by the weathering leaching of readily soluble elements in the watershed （5） The enrichment coefficient and the potential ecological risk assessment show that most of the heavy metal elements in the topsoil of the basin have been affected by human activities, and the enrichment of Cd is most obvious, its Er i value is up to 287.6 which means a highly potential ecological risk; followed by Ni and Cu, Ni Er i value of up to 25.7; Overall, 8 kinds of heavy metal elements in the topsoil comprehensive potential ecological risk (RI) average is 85.5 showing a slight ecological risk. And most of the high RI value areas are located in the main road, farmland and urban areas where human activities are relatively intensive. The accumulation of heavy metals in lake sediments core is lower than that in topsoil, although the accumulation of heavy metals has increased since 1960, but the total cumulative index and potential ecological risk are lower. The results showed the potential ecological risk of elements in sediment core followed the order: Ni(4.7)＞Pb(4.6)＞Cu(4.2) ＞Co(2.6)＞Cr(1.7)＝V(1.7)＞Zn(1.1), and the potential ecological risk of those heavy metals were slight
不同灌溉模式下绿洲土壤盐分再分布研究
No full textIt is an effective measure to manage saline-alkali land and prevent and control theoasis soil secondary salinization through the way of irrigation. Facing serious watershortage in arid areas, this is the basis of determine the salt leaching system ofwater-saving irrigation through further study of soil salt movement characteristicsunder different irrigation mode, which is of great significance for the sustainabledevelopment of oasis agriculture. This study’s operation is in Fukang DesertEcosystem Observation Experimental Station, Chinese academy of sciences, we usethe method of combining field test and laboratory experiments, and discuss thevariation characteristics of spatial and temporal of soil salinity under differentirrigation modes and different irrigation quota combination, and identify theimprovement effects on saline soil and salt leaching efficiency under differentirrigation quota of different irrigation patterns. In this paper, the main conclusions areas follows.(1) Under different irrigation patterns, when the irrigation quota is set at 2500-7000 m3/ hm2, the soil salinity all show a trend of desalination from 0cm to 80cm in the growthperiod, but it shows a trend of increasing in less than 80 cm, this indicates that the soilsalinity changes from surface poly to bottom poly under water leaching. During theirrigation period, the change of soil salinity in the surface layer is more severe than thatin the bottom layer.(2) Under mulch drip irrigation, the greater the amount of irrigation, the higher thedesalination rate, the better the effect of salt leaching. In vertical direction, the greaterthe amount of irrigation, soil salinity leaching deeper, the leaching depth reaches 1.2meters when the irrigation quota is 7000m3/hm2,while the leaching depth reaches onemeters and more than one meter of soil layers when the irrigation quota is 4000m3/hm2and 3000m3/hm2; In horizontal direction, the greater the amount of irrigation, thegreater the difference that soil salinity between film and soil film in different soil layers, when the irrigation quota is 7000m3/hm2, the difference between the membraneand the membrane of different soil salinity is higher than 0.03g/kg.(3)Under the condition of furrow irrigation and border irrigation, the higher salinitybackground value, the better the soil salt leaching. The soil salinity of No. 5 plots forexperimental field is highest than other testing field, its average soil salinity is 0.82g/kg and far more than other plots, the desalination effect is also the best, there is adesalination phenomenon within 1.4 m even deeper soil layer when the irrigation quotais 6000m3/hm2.(4)From looking at the rate of desalination, under the same irrigation quota, thedesalination rate of drip irrigation is lower than the desalination rate of borderirrigation and furrow irrigation, among the desalination rate of drip irrigation under themembrane is below 35%, while the desalination rate of furrow and border irrigationrate are more than 20%; From looking at the leaching efficiency, the same amount ofwater to salt leaching of film drip irrigation is higher than that of border irrigation andfurrow irrigation. In general, the greater the amount of the irrigation water, the betterthe leaching effect of soil salt
粗枝猪毛菜对不同降水添加处理的生理生态响应研究
No full textWater is the primary limiting factor for plant growth in arid desert areas. As the averageannual precipitation became less and uneven distribution in arid area, the frequency of thelarge scale precipitation events which plants can uptake and utilization is lower than thesmall scale precipitation that couldn’t penetrate plant roots for the use of its absorption.With the global climate change, the frequency and intensity of heavy rainfall events areincreasing year by year. In order to explore the water use strategy of plants and the influence for its development,nutrient absorption and the adaptability to the environment under different frequencyrainfall and precipitation. We chose Salsola subcrassa M.Pop. As subject investigated andmade three precipitation patterns: once per month/ 20 mm, twice per month/ 10 mm, forthper month/ 5 mm and contrast. By measuring its physiological and ecological index underthe situation that there have identical precipitation but different frequency. The main resultsare as follows: (1) Small rainfall pulse could only affect the surface soil water content, and a largenumber of precipitation ( > 10 mm) could be affected by soil water content to 50 cm oreven deeper. (2) A large class of precipitation (20 mm) would stimulate the rapid growth of S.subcrassa M.Pop. and the biomass accumulated; Monthly 2/ 10 mm precipitationtreatments resulted in lower R/S. (3) A large amount of precipitation per month promotes the accumulation ofunderground biomass, a small amount of precipitation is conducive to plant seedreproduction. (4) The content of N, P in plants were affected by the frequency of precipitation. N, P inleaves increased first and then decreased, while the content of them in stems and fruitsshowed a trend of gradual accumulation. In this study, through the comprehensive analysis of S. subrassa M.Pop. physiologicaland ecological indicators, we obtained the results which showed the optimum precipitationthreshold of desert plants growth, namely regardless of natural rainfall conditions, themonthly rainfall of 4/ 5 mm wasn’t conductive to the desert plants growth. Therefore, weinitially obtained a large precipitation once a month or several small rainfall was conduciveto plants growth and reproduction
土壤中不同形态锂的浸提方法及应用
No full textA large number of experiments have proved that the arid area of salt-tolerant plantsenrich Lithium ion ,also low dose of Lithium was beneficial to plant growth and the humanbody. So far, soil agricultural analyses were lack of extraction methods of Lithium ion.Therefore, The study took the methods of laboratory research with field investigationcombined , discussed the extraction methods of soil available Lithium, soil exchangeableLithium, soil total Lithium and water soluble Lithium . Based on this method , soil Lithiummorphology and distribution of the Sangong River Basin (FuKang) were studied. Thestudy has important scientific significance and practical value.The main results were asfollows:(1) The extraction methods of soil available Lithium, soil total Lithium, soilexchangeable Lithium and soil water-soluble Lithium have been preliminarily determined.extraction method of available Lithium: the ratio of soil to solvent was 1:10, under thecondition of 1mol/L CH3COOH concussed 6min(200r/min) , the extraction effect was thebest; extraction method of total Lithium: the ratio of soil to solvent of 1:100, under theconditions of concentrated nitric acid and perchloric acid volume ,when the ratio of 3:1 ,the extraction effect was the best; extraction methods of exchangeable Lithium: under thesame experimental conditions, ammonium chloride as extracting agent, the exchangeableLithium leaching effect was the best; extraction methods of water soluble Lithium :in thematerial ratio of 1:10, under the condition of concussed 9min(200r/min) ,the extractioneffect was the best.(2) The effect of pH on the availability of soil Lithium was demonstrated .Underacidic conditions, with the increase of pH value, the content of soil available Lithium wasreduced; under alkaline condition, with the increase of pH value, the content of Lithiumincreases. (3) The morphology and distribution characteristics of Lithium in the soil and water indifferent regions of the basin were preliminarily recognized. There was a significantpositive correlation between the content of soil total Lithium and soil available Lithium inSangong river basin. The distribution characteristics of Lithium content in water and soilshow an increasing trend from upstream to downstream. The content of upstream soilLithium in the lower layer was highest, the content of downstream soil Lithium in themiddle and lower layers was highest, the content of soil Lithium of desert area in the upperlayers was highest
卢旺达植被和湿地监测
No full text准确地认识和预测植被动态变化对于最大限度地解决发展中国家粮食短缺问题至关重要。植被的动态变化趋势与可持续发展紧密相连，例如可以通过观测植被动态变化趋势来制定相应的政策，便于野生动物保护区和栖息地管理。因气候变化、不合理的土地利用加剧了土地的退化，其评估研究是近年来的研究热点。关于植被和土地资源退化的评估研究可以为政府决策提供依据，为全国生态环境保护工作做出针对性的调整，可以大大提高政府管理部门的工作效率。本研究主要是在全球气候变化背景下，对 1990~2015 年卢旺达最大的湿地—Akagera 湿地资源进行分析并对本国的植被退化的状况进行评估。研究内容的第一部分是监测卢旺达 Akagera 湿地并制图，具体方法和结果参见本文第三章， 采用的数据有 Landsat TM，ETM +和 OLI 卫星影像，和 SRTM 数字高程模型（30m 分辨率）。湿地位于卢旺达 -坦桑尼亚边界，沿 Akagera 河由北向南延伸，总面积约为 100,229.76 公顷。水体占到湿地总面积的 30％，河马草和莎草面积分别占 29.8％和29％，还有小部分洪泛平原和沼泽的森林。虽然近些年湿地面积趋于稳定，但由于物种入侵给湿地生态系统带来了很大的不稳定性。通过分析近年来的影像数据，结果表明 Mihindi 湖，Ihema 湖，Hago 湖和Kivumba 湖面积减少，而 Rwanyakizinga 湖面积略微增加。研究内容的第二部分，文章根据 NDVI 和网格气象数据调查了植被的时空特征和植被绿度与降水之间的相互关系，具体方法和结果参见本文第四章。在这项研究中，利用 AVHRR 和 MODIS NDVI 数据集，并结合降雨趋势，对卢旺达植被 1990~2014 年的第一个生长季的时空动态变化进行评估。基于回归分析和赫斯特指数方法，利用 NDVI 和网格气象数据，研究了植被绿度和降水时空分布特征的相互关系。通过研究发现，植被覆盖总体呈上升趋势，年最大变化率为 0.043。在整个研究期间，全国 81.3％的植被有所改善，另外中轻微度退化占到7.5％，大幅度恶化占到 6.6％，其中 Kigali 市和东部省的退化现象严重。对植被类型变化的分析表明，五种植被受到严重威胁：“马赛克草原/森林或灌丛”严重退化，其次是稀疏的植被、草地或木本植被，人工植被和洪泛区阔叶林。通过计算 Hurst 指数，发现指数变化趋势与植被生长态势相一致，可持续的植被面积为 40.16％，不可持续面积为1.67％，不可预测面积为 58.17％。这项研究能够为政府和地方管理部门提供了有关生态保护的信息，为全国环境保护和可持续发展做出有针对性的意见
不同外形粗糙元覆盖沙床面防风蚀效益的风洞模拟实验
No full textIn the hinterland of the Taklimakan Desert, it was found that there were Gravel-size Sand Cemented Bodies(SCB), and that the SCB had similar wind erosion benefits to the gravel-stone. The shapes of Gravel-size Sand Cemented Bodies were irregular. In order to study the inhibitory effect of the geometric shape of the sand surface roughness covering on the surface sand movement, this paper uses the spherical, triangular pyramid, cylindrical, square, pie and hemispherical six kinds of roughness（keep the single grain quality is equal), and choosethe coverage is 10% on the sand surface which is a emprical value that the influence each other is weak.Respectively, in the non-sand wind and sand wind conditions were carried out wind tunnel simulation experiments. Experimental results show:(1) Under the non-sand wind conditions,The wind erosion of the spherical, triangular pyramid, cylindrical and square roughness covering the bed surface is obviously smaller than that of the cake and hemispherical cover, square, and the anti-erosion efficiency of cylindrical, triangular and spherical is also better than pie and hemisphere. In the range of 1cm height (roughness height), the sediment transport capacity is in the order of CK> cake, hemispherical> spherical, cylindrical, triangular,square shapes. When the wind speed 10m/s, 0 ~ 5cm height capcity 90% of the sediment transport sand. With the increase of wind speed, the characteristic value of sand flow structure is easy to be eroded.(2) Under the conditions of sandstorm, the spherical, triangular prismatic and cylindrical covered sand surface is transformed from wind erosion to wind erosion with the increase of wind speed. The wind erosion increases with the increase of wind speed. When the wind speed is more than 10m/s, the sand bed surface showed a strong erosion, which cake shape and hemispherical ‘s sand barrier function is weak, which the wind erosion rate of the largest. On the 1cm height range, the sediment transport rate from large to small in order: CK> pie, hemispherical> spherical,cylindrical, square and triangular pyramid. Under each wind speed, 0 ~ 7cm height contains 90% of the sediment transport. When the wind speed is 8m / s, the surface roughness covering the bed surface exhibits an eutectic equilibrium state. With the increase of the wind speed, the bed surface is easy to be eroded.(3) There are also differences in the wind profiles of the bed with the different shpes element roughness. Within the height of the roughness, the wind speed decreases as the ratio of the roughness direction increases. In the case of spherical and square shapes with the same directional ratio, the chimeric effect of the square-shaped roughness is better than that of the spherical shape. When the height is greater than 7cm, the wind profiles is tend to be stable.(4) Whether it is non-sand wind, or sand wind conditions, the wind erosion are affected by the roughness’s direction of the ratio, height and spacing and other factors, on the conditions of the same coverage, fine high, with a clear boundary roughness’s protection benefits better than lower round roughness