空间结构函数在北京地区气象观测站网设计中的应用

通过统计1978—2000年北京东南低地形区有关台站在春季、夏季、秋季、冬季的逐日平均气温和水汽压的结构函数, 分季节分析了该地区这两个二类气象要素的线段及平面内插精度和台站间距的对应关系, 并根据内插标准误差不超过观测标准误差的原则, 对上述两要素在北京东南低地形区的合理布站方案及间距进行了估算, 可以为2008年北京奥运会气象服务系统建设中气象台站布网建设提供一定的依据。结果表明, 正三角形排列方案为北京东南地区二类气象台站的最佳布站方案, 且布站精度应小于等于16 km。     

引入Himawari-8卫星数据协变量的能见度样条插值方法

在ANUSPLIN薄盘光滑样条插值中,高相关协变量的选取决定了插值结果的精确性。本文选取2017—2019年大雾和霾能见度较差的天气过程,利用183个能见度观测站点对能见度进行插值,引入Himawari-8卫星的通道数据和DEM数据作为协变量对能见度的插值结果进行改进,并对能见度插值结果进行对比分析。研究表明,引入Himawari-8数据和DEM数据作为协变量的能见度插值结果在精度上有显著提高,尤其对雾区和霾区的边界范围和纹理的反演更为准确,基于Himawari-8卫星数据和气象监测站点的观测数据,使用协变量的方法进行能见度插值可以做为能见度监测网格化的一种有效途径。     

基于地统计方法的气候要素空间插值研究

在回顾了地统计学的产生、发展及其基本原理的基础上,对于目前众多可以提供计算网格的气候要素的空间插值方法中,具体探讨了普通克里格法和协同克里格法。将甘肃省1961—1990年30年平均降水量和蒸发量作为区域化变量,根据不同的半变异函数理论模型,采用普通克里格法和双变量协同克里格法,通过对比分析得到：（1）不论是多年均降水量还是多年平均蒸发量在空间上都呈现明显的梯度变化,二者的空间变程都很大,而降水量变化幅度更大。降水量从东南部向西北部逐渐减少,蒸发量则相反,从东南向西北逐渐增加。（2）基于地统计的插值方法,根据半变异函数云图和试验方差最小的原理,选择合适的半变异函数理论模型进行变量的空间插值,能够较好地模拟区域化变量的空间连续分布格局,并取得较好的效果。对比普通克里格法和协同克里格法,后者增加了高度对降水量和蒸发量的影响,在空间分布上更为合理,插值的精度也要明显好于普通克里格法。（3）采用地统计方法虽然在总体上能够较好地反映气候要素的空间分布格局,但检验显示,两种方法空间插值的精度都还不是很高,插值的精度还有待进一步提高。     

基于残余插值的卷积神经网络去马赛克算法

在去马赛克问题中,为了精确插值倾斜边缘并提高结果图像的整体质量,提出一种基于残余插值的卷积神经网络去马赛克算法.针对Bayer格式的颜色滤波阵列,插值绿色平面时,对于红蓝通道信息不全的问题,采用同通道邻近像素值近似代替,综合考虑3个通道的梯度,运用倾斜方向的边缘检测算子,将倾斜边缘分为不同方向的边缘分别插值.在插值完成后,利用深度卷积神经网络,进一步训练插值结果.在标准的IMAX数据集上,与目前流行的算法相比,本文算法视觉上更接近原图,具有更高的峰值信噪比和更短的运行时间.     

气象资料三维化技术中的插值问题

通过对不同源气象资料及数字地理信息资料的插值，实现了不同气象资料与地理信息资料分辨率的协调；从而将多种信息叠加到一起，实现了多源资料的二维、三维仿真显示。这对于模拟真实的大气空间结构、理解地形及植被对大气运动的影响、辨识各种天气系统及多种信息的融合等有积极意义。     

地统计学分析技术及其在气象中的适用性

首先论述了地统计学的一些特点，然后从变异函数和Kriging插值两个方面介绍了地统计学的分析技术，最后讨论了地统计学在气象研究中的适用性。     

SAMPLING REMOTELY SENSED IMAGERY FOR STORAGE,RETRIEVAL, AND RECONSTRUCTION*

A major difficulty in remote sensing is handling the many data from sensors aboard aircraft and satellites. In this paper we identify an optimal procedure for sampling remotely sensed data before their storage or on their retrieval. The procedure depends on spatial correlation in the scene and uses kriging to estimate values that have been lost. An example in which data from an airborne multispectral scanner could be diminished to only about one tenth without serious loss of precision illustrates the method.     

长江口滨岸湿地无机氮界面交换通量量算

基于3年长江口滨岸湿地沉积物－水界面无机氮季节性交换通量连续实测数据,建立无机氮界面交换通量空间插值模型与量算模型,对无机氮界面交换通量季节性空间分布特征、滨岸湿地不同岸段无机氮季节性界面交换总通量量算等研究。结果表明：修正GIDS插值模型在无机氮界面交换通量空间插值预测过程中精度明显优于IDS方法,而略优于普通Kriging方法;长江口滨岸湿地沉积物－水界面无机氮交换通量空间分布在不同季节表现出复杂的空间分异特征;利用修正GIDS插值模型对长江口滨岸湿地无机氮交换通量进行空间插值过程中,为提高通量量算模型精度,应采用1.2'×1.2'的空间尺度为最佳;长江口滨岸湿地无机氮界面交换总通量量算表明,长江口滨岸湿地在春季向水体释放无机氮,是水体无机氮的释放源,释放量为1.33×10⁴ t,夏季、秋季和冬季表现为净化水体中无机氮,是水体无机氮的吸收汇,分别净化无机氮量为4.36×10⁴ t、6.81×10⁴ t和2.24×10⁴ t,全年总体表现为净化水体中无机氮,净化量为12.1×10⁴ t;长江口多年水体中无机氮通量多项式拟合分析得出,2002~2004年3年长江口水体中无机氮通量平均值为52.6×10⁴ t,滨岸湿地对长江口水体中无机氮的年均净化率达23.0%。     

Incorporating GIS Building Data and Census Housing Statistics for Sub-Block-Level Population Estimation

This article presents a deterministic model for sub-block-level population estimation based on the total building volumes derived from geographic information system (GIS) building data and three census block-level housing statistics. To assess the model, we generated artificial blocks by aggregating census block areas and calculating the respective housing statistics. We then applied the model to estimate populations for sub-artificial-block areas and assessed the estimates with census populations of the areas. Our analyses indicate that the average percent error of population estimation for sub-artificial-block areas is comparable to those for sub-census-block areas of the same size relative to associated blocks. The smaller the sub-block-level areas, the higher the population estimation errors. For example, the average percent error for residential areas is approximately 0.11 percent for 100 percent block areas and 35 percent for 5 percent block areas.     

Use of an expert system to map forest soils from a geographical information system

Abstract

Mapping forest soils using conventional methods is time consuming and expensive. An expert system is described and applied to the mapping of five forest soil-landscape units formed on a single granitoid parent material. Three thematic maps were considered important in influencing the distribution of soils. The first showed the distribution of nine classes of native eucalypt forests, and the second and third were derived from a digital elevation model and represented slope gradient and a soil wetness index combined with topographical position. These layers were input to a raster based geographical information system (GIS) and then geometrically co-registered to a regular 30 m grid. From a knowledge of soil distributions, the relationships between the soil-landscape units and the three data layers were quantified by an experienced soil scientist and used as rules in a rule based expert system. The thematic layers accessed from the GIS provided data for the expert system to infer the forest soil-landscape unit most likely to occur at any given pixel. The soil-landscape map output by the expert system compared favourably with a conventional soil-landscape map generated using interpretation of aerial photographs.