基于时间序列分析和灰色理论的建筑物沉降预测模型研究

基于时间序列分析方法建立建筑物沉降预测模型,其中通过二次移动平均法提取出沉降监测序列中的趋势项,并在此基础上采用灰色系统理论动态GM（1,1）模型进行趋势项预测。实际算例结果表明,该模型能够较好地预测沉降变化的发展趋势,并具有较高的预测精度,证明了该预测模型具有一定的可行性和有效性。     

侧视雷达影像距离-共面模型严密定位

本文对现有侧视雷达遥感影像的几何构像模型在摄影测量应用中的不足进行了理论分析,以外方位元素作为定向参数,依次建立了像点坐标显函数形式的距离-共面(R-Cp)方程、地心直角坐标系中星载侧视雷达影像的距离-共面方程、以及星载侧视雷达遥感影像的严密定位模型,并进行了稀少控制点条件的星载TerraSAR-X影像定位试验。理论和试验表明,本文所建立的R-Cp严密定位模型,使得雷达影像像点量测坐标作为摄影测量观测值的属性得到体现,容易吸收和利用光学遥感影像基于共线方程模型发展起来的成熟的数字摄影测量数据处理方法,有利于提高雷达遥感影像摄影测量数据处理的严密性、稳定性、可靠性及数据处理效率。     

The Impact of Mid- and High-Latitude Rossby Wave Activities on the Medium-Range Evolution of the EAP Pattern During the Pre-Rainy Period of South China

Based on the NCEP DOE AMIP II daily reanalysis data (1979{2005), the evolution of the East Asia/Pacific(EAP) teleconnection pattern during the pre-rainy period of South China is studied on the medium-range time scale. It is found that positive and negative EAP patterns share a similar generation process. In the middle and upper troposphere, Rossby wave packets emanating from the northeast Atlantic or Europe propagate toward East Asia along the Eurasian continent waveguide and finally give rise to the three anomaly centers of the EAP pattern over East Asia. Among the three anomaly centers, the western Pacific subtropical center appears the latest. Rossby wave packets propagate from the high latitude anomaly center toward the mid-latitude and the subtropical ones. The enhancement and maintenance of the subtropical anomaly center is closely associated with the subtropical jet waveguide and the incoming Rossby wave packets from the upstream. In the lower troposphere, Rossby wave packets emanate from the subtropical Asia toward East Asia. Positive and negative EAP patterns could not be regarded as "mirrors" to each other with simply re- versed phase. For the positive pattern, the positive height anomaly center around the Scandinavia Peninsula keeps its strength and position during the mature period, and the Rossby wave packets thus propagate persistently toward East Asia, facilitating a longer mature time of the positive pattern. As for the formation of the negative EAP pattern, however, the incoming Rossby wave energy from the upstream contributes to both the enhancement and southeastward movement of the negative anomaly belt from the Yenisei River to the Bering Strait and the positive anomaly center around Mongolia. At the peak time, the two anomlous circulations are evolved into the Northeast Asia and the mid-latitude anomaly centers of the negative pattern, respectively. The energy dispersion of Rossby wave packets is relatively fast due to the predominant zonal circulation in the extratropics, causing a shorter mature period of the negative pattern. During the pre-rainy period of South China, the prevalence of the EAP pattern signiˉcantly affects the rainfall over the region south of the Yangtze River. The positive (negative) EAP pattern tends to causepositive (negative) precipitation anomalies in that region. This is di?erent from the earlier research findingsbased on monthly mean data.     

基于SWAT模型的汉江流域径流模拟

应用SWAT(Soil and Water Assessment Tool)分布式水文模型对汉江流域1971-2000年30年逐月径流进行了模拟.结果表明:模型模拟精度高于评价标准(模拟效率Ens>0.5,相关系数r 2>0.6),SWAT模型适用于汉江流域的径流模拟;水量平衡各要素中,30年月、年平均蒸散发量、地表径流量、土壤对地下水补给量、土壤含水变化量、地下水侧流量分别占降水量的55.97%、25.88%、17.64%、0.26%、0.25%,蒸散发是该流域水量的主要输出项;各月30年平均降水量变化趋势与地表径流量变化趋势较一致,而与基流量变化趋势一致性较差;30年流域降水量年变化趋势与地表径流量、基流量的变化趋势较一致;30年月、年地表径流量对降水的响应程度高于基流.     

沈阳市新城子铬渣堆存区土壤铬污染分布及形态研究

采用 Tessier A连续提取法研究分析了沈阳市新城子铬渣堆存区土壤中重金属铬的污染分布和迁移转化规律。结果表明：土壤中重金属铬的5 种形态分布, 主要以残渣态和碳酸盐结合态为主,分别占总量的49.74%和21.40%,而有机结合态含量最低,占总铬含量的6.25%。不同的功能区域铬的形态分布有所不同。总体的分布特征是残渣态大于碳酸盐结合态大于交换态大于铁锰氧化态大于有机态。     

两类不同月平均气温空间推算方法的对比

利用全国660个常规气象站40年(1961-2000年)整编气象资料.采用逆距离权重反比法、样条函数法和普通克立格法等常用的3种插值方法,分析了直接插值法和综合余项法对气温插值的影响,提出了去除气温形成中的确定性部分后,以随机项进行插值可提高气温插值精度。并从空间上、时间上对比眲不同插值方法的误差,最后分析了气象站的空间分布密度对插值方法的敏感性。验证结果表明:除个别月份外,综合余项法的各项平均绝对误差均在1℃以内,比直接插值法减小了0.6～1.6℃,精度提高了38%～85%;且综合余项法的精度不依赖于台站密度的大小、插值方法的不同,具有较高的精确性和稳定性,这说明影响空间插值精度的关键因子并非是气象观测站点密度的提高、空问插值方法的改进。     

A Case Study on a Quasi-Stationary Meiyu Front Bringing About Continuous Rainstorms with Piecewise Potential Vorticity Inversion

A 4-day persistent rainstorm resulting in serious flooding disasters occurred in the north of Fujian Province under the influences of a quasi-stationary Meiyu front during 5-8 June 2006. With 1°× 1° latitude and longitude NCEP reanalysis data and the ground surface rainfall, using the potential vorticity （PV） analysis and PV inversion method, the evolution of main synoptic systems, and the corresponding PV and PV perturbation （or PV anomalies） and their relationship with heavy rainfall along the Meiyu front are analyzed in order to investigate the physical mechanism of the formation, development, and maintenance of the Meiyu front. Furthermore, the PV perturbations related to different physics are separated to investigate their different roles in the formation and development of the Meiyu front. The results show： the formation and persistence of the Meiyu front in a quasi-WE orientation are mainly due to the maintenance of the high-pressure systems in its south/north sides （the West Pacific subtropical high/ the high pressure band extending from the Korean Peninsula to east of North China）. The Meiyu front is closely associated with the PV in the lower troposphere. The location of the positive PV perturbation on the Meiyu front matches well with the main heavy rainfall area along the Meiyu front. The PV inversion reveals that the balanced winds satisfying the nonlinear balanced assumption represent to a large extent the real atmospheric flow and its evolution basically reflects the variation of stream flow associated with the Meiyu front. The unbalanced flow forms the convergence band of the Meiyu front and it mainly comes from the high-pressure system in the north side of the Meiyu front. The positive PV perturbation related to latent heat release in the middle-lower troposphere is one of the main factors influencing the formation and development of the Meiyu front. The positive vorticity band from the total balanced winds is in accordance with the Meiyu front band and the magnitude of the posit     

A Diagnostic and Numerical Study on a Rainstorm in South China Induced by a Northward-Propagating Tropical System

A strong cyclonic wind perturbation generated in the northern South China Sea （SCS） moved northward quickly and developed into a mesoscale vortex in southwest Guangdong Province, and then merged with a southward-moving shear line from mid latitudes in the period of 21-22 May 2006, during which three strong mesoscale convective systems （MCSs） formed and brought about torrential rain or even cloudburst in South China. With the 1° ×1° NCEP （National Centers for Environment Prediction） reanalysis data and the Weather and Research Forecast （WRF） mesoscale model, a numerical simulation, a potential vorticity inversion analysis, and some sensitivity experiments are carried out to reveal the formation mechanism of this rainfall event. In the meantime, conventional observations, satellite images, and the WRF model outputs are also utilized to perform a preliminary dynamic and thermodynamic diagnostic analysis of the rainstorm systems. It is found that the torrential rain occurred in favorable synoptic conditions such as warm and moist environment, low lifting condensation level, and high convective instability. The moisture transport by strong southerly winds associated with the rapid northward advance of the cyclonic wind perturbation over the northern SCS provided the warm and moist condition for the formation of the excessive rain. Under the dynamic steering of a southwesterly flow ahead of a north trough and that on the southwest side of the West Pacific subtropical high, the mesoscale vortex （or the cyclonic wind perturbation）, after its genesis, moved northward and brought about enormous rain in most parts of Guangdong Province through providing certain lifting forcing for the triggering of mesoscale convection. During the development of the mesoscale vortex, heavy rainfall was to a certain extent enhanced by the mesoscale topography of the Yunwu Mountain in Guangdong. The effect of the Yunwu Mountain is found to vary under different prevailing wind directions and intensities. The location o     

印度夏季风与中国华北降水的遥相关分析及数值模拟

20世纪80年代中国学者揭示了印度夏季风与中国华北降水的正相关关系,以后国内外又有一些研究证实了这种正相关关系的存在.文中利用1951-2005年多种气象资料和数值模拟方法,详细讨论了印度夏季风和中国华北地区夏季降水的关系,并针对由印度西北部经青藏高原到中国华北地区形成的正、负、正的遥相关型,从动力因子和热力因子两方面探讨了其中的内在联系,所得结果不但确证了以往的结论,而且进一步揭示了印度夏季风对华北地区降水的影响机制.结果表明:(1)印度夏季风强(弱)时,华北地区容易出现降水偏多(少)的天气;华北地区降水偏多(少)时,印度夏季风偏强(弱)的机率却低一些,这说明印度夏季风的异常变化对华北地区夏季降水有更大的影响.(2)印度夏季风强度主要受印度季风槽的影响,在印度季风槽加深的同时,中高纬的低压槽也加深发展,而这时西太平洋高压脊西伸,来自低纬的西南风水汽输送和源于西太平洋的副热带高压南侧的东南风水汽输送共同作用,有利于华北地区的降水偏多;反之则不利于华北地区的降水.(3)区域气候模式模拟结果也很好地模拟出印度夏季风和华北夏季降水的遥相关关系,其相应的环流异常系统与诊断分析结果非常一致,这从另一方面证实了这种遥相关关系的存在和可靠性.