基于核主成分分析和粒子群优化支持向量机的滑坡位移预测

利用核主成分分析法对滑坡位移影响因子进行特征提取,以获得的主成分作为支持向量机的特征向量建立支持向量机模型,其中模型参数通过粒子群算法进行选择优化,构建出核主成分分析和粒子群优化支持向量机协同模型,对滑坡相对位移进行预测.预测结果的平均绝对误差和相对误差分别为0.760和7.563％,与其他预测模型相比,其拟合和泛化能力最优,表明核主成分分析和粒子群优化支持向量机协同模型的预测结果与实际监测值具有很好的一致性.     

长江中上游冬季山地雾边界层特征及生消过程分析

利用2010年12月在湖北宣恩观测山地雾获得的边界层廓线、雾滴谱、能见度资料,分析了该地雾过程的边界层特征及其生消过程。结果表明:1)宣恩山地雾主要由夜间辐射冷却引起,且能见度多在200 m以上;垂直发展深厚,成熟时厚度达到400~600 m。2)夜间风场主要由山风环流控制,风向多为东南风;入夜及雾生前期,地面风速不超过0.5 m/s,雾消前增大至2.0 m/s左右。3)雾生前观测到"C"字型温度层结,中下层气温降温率在0.3~1.0℃/(100 m)之间;结合该时段近地层露点温度逆温,离地200 m左右率先饱和成云;雾消时低空相对湿度依然保持较大值,重新变为空中雾层。4)雾前1~2 h地面及植被表明温度显著上升,个别升温率达1℃/h,对应时段地面相对湿度达到饱和,与其他地区有明显区别,对预报宣恩山地雾有积极意义。     

THE CHARACTERISTICS OF THUNDERSTORM FREQUENCY VARIATION AND THEIR POSSIBLE RELATION WITH THE ADJUSTMENT OF CROP DISTRIBUTION IN THE LEIZHOU PENINSULA

In order to research possible influences of the adjustment of plant distribution on the development frequency of thunderstorms over the Leizhou Peninsula, mathematic statistic methods, including correlation analyses, 11 kinds of fitting models and all-variable regression methods, were used for analyses and research. The results show that the average trend of the number of annual thunderstorm days is descending obviously, and there are thunderstorms in all seasons, in which warm post-midday thunderstorms have taken up the most part, and high frequency is found from May to September, and the starting and ending dates of thunderstorms have a great annual discrepancy. The vegetation structure has been improved along with the reduction of rice fields and the area increment of sugarcane and fruits planting, which results in the decrease of the number of thunderstorm days; the change in the characteristics of winter spare fields, which is caused by the planting of vegetables, limits the formation of thunderstorms in early winter and late spring. Meanwhile, the area adjustment of peanut planting has little influence on the variation of thunderstorm days. The adjustment of principal crop distribution, such as rice, sugarcane, fruits and vegetables, may have obvious influence on the formation of thunderstorms, and sugarcane has the largest effect, followed in turn by rice, vegetables and fruits, and the adjustment of crop distribution has little influence on the starting and ending dates of thunderstorms.     

Vertical Structures of Convective and Stratiform Clouds in Boreal Summer over the Tibetan Plateau and Its Neighboring Regions

Cloud is essential in the atmosphere, condensing water vapor and generating strong convective or large-scale persistent precipitation. In this work, the relationships between cloud vertical macro- or microphysical properties, radiative heating rate, and precipitation for convective and stratiform clouds in boreal summer over the Tibetan Plateau (TP) are analyzed and compared with its neighboring land and tropical oceans based on CloudSat/CALIPSO satellite measurements and TRMM precipitation data. The precipitation intensity caused by convective clouds is twofold stronger than that by stratiform clouds. The vertical macrophysics of both cloud types show similar features over the TP, with the region weakening the precipitation intensity and compressing the cloud vertical expansion and variation in cloud top height, but having an uplift effect on the average cloud top height. The vertical microphysics of both cloud types under conditions of no rain over the TP are characterized by lower-level ice water, ice particles with a relatively larger range of sizes, and a relatively lower occurrence of denser ice particles. The features are similar to other regions when precipitation enhances, but convective clouds gather denser and larger ice particles than stratiform clouds over the TP. The atmospheric shortwave (longwave) heating (cooling) rate strengthens with increased precipitation for both cloud types. The longwave cooling layer is thicker when the rainfall rate is less than 100 mm d^?1, but the net heating layer is typically compressed for the profiles of both cloud types over the TP. This study provides insights into the associations between clouds and precipitation, and an observational basis for improving the simulation of convective and stratiform clouds over the TP in climate models.     

郯庐断裂带早白垩世走滑运动中的构造、岩浆、沉积事件

郯庐断裂带内一系列走滑糜棱岩类的^40Ar/^39Ar测年表明，郯庐断裂早白垩世发生了左旋走滑运动。这一大规模的走滑运动，造成了两类走滑构造，一类为变质岩中低绿片岩相左旋韧性剪切带，另一类为中生代火成岩、沉积岩中的脆性、脆-韧性左行平移断层。这反映断裂带的走滑运动从早白垩世初期持续到早白垩世后期。断裂带的走滑运动诱发大规模的、以富钾、中酸性为主的岩浆活动。地球化学分析显示，这些岩浆岩既有壳源的信息，也有幔源的贡献，反映是断裂减压、壳-幔相互作用下形成的岩浆活动，也暗示断裂带在走滑期切入壳-幔边界。该断裂带走滑运动中，除了在莱阳盆地形成了拉分盆地外，还在合肥盆地东部造成了走滑挠曲盆地，控制下白垩统朱巷组的沉积，郯庐断裂带早白垩世走滑运动中的构造、岩浆、沉积事件，是西太平洋伊泽纳崎板块高速斜向俯冲的结果，属于滨太平洋构造。     

冀北滦平盆地陆相侏罗系-白垩系界线候选层型剖面初步研究

在发现陆相侏罗系—白垩系界线地层连续剖面的基础上,补充大北沟组和大店子组的含义,将2组系统分为7个岩段,命名4个标志层;确定年代地层层序,完善大北沟阶和义县阶定义内容;研究重点门类化石分布和演化,建立系统生物地层分带序列,包括7个介形虫带和6个叶肢介带;划分陆相生物群发展阶段,将侏罗系—白垩系界线置于“早期热河生物群”阶段的底部;开展旋回地层和层序地层学研究,建立地层等时格架,识别盆地演化的3个阶段和5个构造期;测得界线层型剖面点存在O同位素高值异常;锆石206Pb/238U测得张家口组顶部年龄为135.4Ma±1.6Ma,大北沟组中部为133.9Ma±2.5Ma和130.1Ma±2.5Ma。综合多学科研究成果,将界线层型剖面点定在张家沟剖面第9层底,以介形虫化石Cyprideastenolonga的首现为标志。     

历史专题图的大空间范围湿地专题图自动更新

湿地专题图的更新无论是对湿地研究还是湿地管理和保护都具有重要价值。但是由于湿地本身具有显著的时空动态性和空间异质性特征,使得大空间范围湿地专题图的更新面临着周期长、时效性差的挑战。为应对这一挑战,实现大空间范围湿地地图的快速更新,本文提出一种通过提取历史湿地专题图中的信息,对新遥感影像进行自动化的湿地分类制图方法——"迭代解译再组织" IIR (Iterative Interpretation and Reorganization)。针对湿地空间异质性强、稳定样本获取困难等特点,IIR方法通过分别获取不同湿地类型的空间信息和类别属性两个步骤完成湿地的自动更新。为验证该方法在大空间范围湿地图更新中的应用效果,随机选取了位于高海拔地区、高纬度地区、低纬度地区和滨海地区等不同自然地理环境的4个湿地保护区(若尔盖湿地保护区、莫莫格湿地保护区、鄱阳湖湿地保护区和黄河三角洲湿地保护区)进行验证。结果表明IIR方法的湿地制图的总体精度在70%—90%,总体上优于传统监督分类方法。IIR方法对于大的时空尺度背景下湿地专题图更新面临的高时空动态特征具有较好的解决能力。     

钟形地形动力抬升和重力波传播与地形云和降水形成关系研究

地形云和降水过程在区域水循环、水资源、生态环境及气候变化中具有十分重要的作用。本文利用中尺度数值模式WRF 数值模拟试验,以及通过引入表示大气层流速度、层结稳定度和地形特征的关系参数——湿Froude 数(F_w),研究了北京2009 年5 月1 日湿条件不稳定大气层结下,地形云和降水形成过程与地形动力抬升和地形重力波传播之间的关系及形成机理。研究表明,在地形最大高度2 km、半宽10 km 的条件下,层流速度从2.5 m/s 逐步增加到25 m/s 时,对应的湿F_w 数从0.19 增加到1.81。当F_w≤1 时,地形的阻挡起主要作用,由地形抬升形成的地形云主要产生在迎风坡一侧。地形重力波主要产生在迎风坡,并向上游传播,先形成层状云,最后演变为准稳定浅对流波状云。最大降水主要发生在紧靠山顶的迎风坡一侧,但当F_w 很小时,地形云不产生降水。当F_w>1 时,地形抬升形成的云主要发生在山顶附近,而地形重力波主要形成在背风坡,并向下游方向传播,形成准稳定波状云。最大降水主要产生在紧靠山顶的背风坡一侧。另外,在弱湿条件不稳定大气层流下,地形降水主要由地形动力抬升造成的暖云微物理过程产生,地形重力波形成的波状云几乎不产生降水。     

MODIS监测雾的方法及分析

根据云雾及下垫面在可见光、长波红外和中红外波段的反射及辐射特性差异，结合MODIS资料，得出不同的波谱廓线并进行波谱分析。利用分析结果给出多通道综合阈值法监测大雾的流程，并用此方法进行了个例分析。结果表明：MODIS资料在雾监测方面有很好的应用潜力；中红外通道在雾监测上有独特的优势。     

地形对2011年9月华西致灾暴雨强迫作用的数值模拟研究

运用GRAPES_Meso模式对2011年9月16-18日发生在陕西、四川的连续特大致洪暴雨过程进行数值模拟.通过对比3套敏感性试验结果,揭示了气流与地形相互作用对本次致灾暴雨的影响,结果如下:(1)16-18日在台风和蒙古高压共同影响下,850 hPa在黄、渤海形成偏东水汽通道,使大量水汽经华北平原输送至华西地区,气流被秦岭分割为南北两支,北支在秦岭北侧受到迎风坡阻挡,形成强迫抬升和水汽辐合中心;南支暖湿气流从东部灌入汉中平原,受到“喇叭口”地形挤压而辐合上升.(2)平原与高大山脉的交错相间地形导致条带状正负垂直运动带产生,在垂直方向上形成强烈的抽吸作用,加之该地区16-18日丰沛的水汽交汇,从而引发大范围强降水.(3)海拔高度与地表起伏度均对降雨有较大影响,在同样海拔情况下,地表起伏度越大,就越容易产生暴雨.