高速铁路通用地面控制测量数据处理自动化系统研制

介绍了具有自主知识产权的高速铁路通用地面控制测量数据处理自动化系统软件（FSDI-GDPAS）的总体设计、功能模块设计及其涉及到的关键算法与相关理论,并通过具体工程实践说明软件的有效性和可靠性。     

CBERS-1CCD相机飞行绝对辐射标定试验地面同步测量与场地辐射特性分析

中国对地观测遥感卫星辐射校正场(即敦煌场)位于中国敦煌市西戈壁沙漠的西北角。整个敦煌场地面比较均匀、平坦,面积为30×40km²;测试区(标定区)面积为400×400m²,位于场区的中心位置。2000年8月底至9月初,中国资源卫星应用中心联合安徽光机所在敦煌场地进行了一次CBERS-1CCD传感器飞行绝对辐射标定试验。地表反射率和大气光学特性地面同步测量结果显示:敦煌场地的地面均匀性好,各个通道反射率的变化系数(即相对变化百分比)均小于3%。在可见光、近红外光谱范围内,地面光谱反射率随波长增加逐步增大,例如,在485nm波长处的地面反射率值约为0.18,在830nm波长处的反射率值约为0.26。大气光学特性测量结果显示:0.55μm波长处的大气总光学厚度(≈0.34)和气溶胶光学厚度(≈0.26)相对较小,大气水汽含量也较小。     

Nitrogen dioxide DOAS measurements from ground and space: comparison of zenith scattered sunlight ground-based measurements and OMI data in Central Mexico

The use of satellite data in combination with ground-based measurements can provide valuable information about atmospheric chemistry and air quality. In this study, ground-based Differential Optical Absorption Spectroscopy (DOAS) measurements of nitrogen dioxide (NO₂) conducted in central Mexico are compared with the space-borne Ozone Monitoring Instrument (OMI) dataset of 2006-2011. Ground-based measurements exhibited large day-to-day variations and were on average three times higher than the space-borne derived average over the observation site. This difference is attributed to strong horizontal inhomogeneity of the lower layer of the measured NO₂ columns, sampled over a large footprint from the satellite instrument. Also, a reduced sensitivity of the satellite observation near the surface, where the largest concentrations are expected, could be responsible for this large discrepancy. From the analyzed OMI dataset, distribution maps of NO₂ above central Mexico were reconstructed, allowing to identify three main areas with increased NO₂ column densities: The dominating metropolitan area of Mexico City, the heavily industrialized region of Tula to the north and the Cuernavaca valley to the south. In this analysis, seasonal variability of NO₂ columns over central Mexico was detected, finding higher NO₂ columns during the dry and cold season, followed by the dry and warm period, and finally the lowest NO₂ columns were found during the rainy season. Pollution transport of this gas from Tula into Mexico City, as well as towards the Cuernavaca valley, is evident from this dataset.     

地基SAR数据优化及灾变体面积预警预报分析

针对地基SAR异常数据难以识别、潜在滑坡体发展特征及规律不明显、临滑面积估算难度大的问题,本文以甘肃某矿山滑坡数据为基础,介绍了地基SAR形变数据的处理方法,通过Matlab软件有效地识别、筛选、剔除了异常形变数据,并以色彩差异进行区分,进一步突显了不同阶段潜在灾变体面积的演化规律。基于地基雷达监测原理,提出一种多边形面域估算方法,实现潜在危险区域面积的估算。研究不等周期处理的速度倒数曲线组,发现速度倒数平方法能够进一步放大特征趋势,预测结果准确、预报效果好,为实现矿山滑坡超前预警预报提供了新的思路。     

Integration of air pollution data collected by mobile sensors and ground-based stations to derive a spatiotemporal air pollution profile of a city

ABSTRACT

Air pollution has become a serious environmental problem causing severe consequences in our ecology, climate, health, and urban development. Effective and efficient monitoring and mitigation of air pollution require a comprehensive understanding of the air pollution process through a reliable database carrying important information about the spatiotemporal variations of air pollutant concentrations at various spatial and temporal scales. Traditional analysis suffers from the severe insufficiency of data collected by only a few stations. In this study, we propose a rigorous framework for the integration of air pollutant concentration data coming from the ground-based stations, which are spatially sparse but temporally dense, and mobile sensors, which are spatially dense but temporally sparse. Based on the integrated database which is relatively dense in space and time, we then estimate air pollutant concentrations for given location and time by applying a two-step local regression model to the data. This study advances the frontier of basic research in air pollution monitoring via the integration of station and mobile sensors and sets up the stage for further research on other spatiotemporal problems involving multi-source and multi-scale information.     

基于北斗导航系统的我国地基增强格网模型研究

基于全国均匀分布的210个北斗地基增强基准站观测数据,提出基于非差非组合精密单点方法获取空间相关的延迟误差及残差,研究利用反距离加权法、克里金插值法以及球谐函数法建立了中国区域的三种地基增强格网模型。使用单频伪距单点定位方法对中国区域的北斗地基增强格网模型定位精度进行了评估,验证结果表明本文建立的格网模型的定位精度达到米级,可满足大众用户的需求。     

利用湖南CORS网监测分析湘北一次局地暴雨水汽场时空变化

基于72个湖南连续运行参考站 (CORS) 反演得到的可降水量 (PWV) ,针对2015-04-03~04-04湘北地区一次局地暴雨,结合温度和气压等大气热动力条件,分析湖南省PWV时间序列及其平面动态分布变化,并总结此次暴雨过程中水汽场变化规律。研究结果表明,作为降水的必要条件,PWV峰值越大降水概率越高,当PWV突破48 mm并首次降低时,随后1 h内会出现降水;当PWV持续增强达到峰值50 mm之后再次下降时,PWV增量变化很大程度上决定着雨势的大小及降雨持续时长;气温和气压等热动力条件也对雨势预测有一定的指示作用;PWV分布变化可对实际降水范围（落区）趋势作出较为准确的预测。     

基于奇异谱分析的地基GPS反演可降水量可行性分析

对微波辐射计观测与地基GPS反演的可降水量数据分1个长时段和2个短时段进行奇异谱分析,提取两种数据在不同时段的主体趋势及周期项,验证地基GPS反演可降水量的可行性。结果表明,与微波辐射计观测数据相比,地基GPS反演可降水量数据均方根误差在2 mm左右,主体趋势具有较强的相关性,周期相同或相近,利用地基GPS反演可降水量是可行的。     

Depletion of Column Ozone in the Arctic During the Winters of 1993-94 and 1994-95

The total ozone reduction in the Arctic during the winters of 1993/94 and 1994/95 has been evaluated using the ground-based total ozone measurements of five SAOZ spectrometers distributed in the Arctic and from number density profiles of a balloon-borne version of the instrument. The ozone change resulting from transport has been removed using a 3D Chemistry Transport Model (CTM) run without chemistry. A cumulative total ozone depletion at the end of winter in March of 18% ± 4% in 1994 and of 32% ± 4% in 1995 was observed within the polar vortex, and of 15% ± 4% in both years outside the vortex. This evaluation is not sensitive to the vertical transport in the model. The periods, locations and altitudes at which ozone loss occurred were tightly connected to temperatures lower than NAT condensation temperature. The maximum loss was observed at 50 hPa in 1994 and lower, 60-80 hPa, in 1995. Half of the depletion in 1994 and three quarters in 1995 occurred during the early winter, showing that a late final warming is not a prerequisite for large ozone destruction in the northern hemisphere. The timing, the geographical location and the altitude of the ozone losses are well captured by the 3D CTM photochemical model using current chemistry, but its amplitude at low sun during the early winter, is underestimated. The model simulations also capture the early season reductions observed outside the vortex. This suggests that the losses occurred in situ in the early winter, when low temperatures are frequent, and not later in March, when ozone is most reduced inside the vortex, which would be the case if leakage from the vortex was the cause of the depletion.     

地基雷达的微波面散射模型对比与土壤水分反演

为了探究地基合成孔径雷达(cGBSAR)后向散射信号的时空变化规律和研究雷达土壤水分反演的影响因素,在内蒙古闪电河流域的昕元牧场站进行了地基雷达观测试验,本文结合以上观测试验的地基雷达数据进行波段、入射角度、极化通道3个雷达参数以及地表粗糙度参数对雷达的后向散射系数影响的分析,然后利用以上分析结果选择地表微波面散射模型...