CLIMATIC CHARACTERISTICS OF NET RADIATION IN THE EARTH-ATMOSPHERE SYSTEM OVER CHINA*

Investigated are effects of the total cloudiness and other factors on earth-atmosphere net radiation(EANR) and analyzed is its relation to other components and ground surface net radiation in the context of ERBE and ISCCP.Evidence suggests that planetary scale albedo and earth-atmosphere short wave absorption radiation have maximum effect on the net radiation under study,with the influence of cloud and latitude displayed predominantly through the two factors;OLR has relatively weak effect;the earth-atmosphere net radiation is well correlated with surface net radiation.Analysis is also performed of the geographic distribution of the earth-atmosphere net radiation throughout China,and the annual curve of the net radiation on a local basis is marked by high(low) value in summer(winter) with the impact of factors.including total cloudiness responsible largely for the shift of the months with maximum.     

岩石质量指标(RQD)的各向异性分析

各向异性是工程岩体的重要工程特性, 岩石质量指标RQD具明显的各向异性。本文运用结构面网络模拟技术, 通过结构面间距、倾角、相对夹角以及结构面组数的敏感性分析, 探讨了RQD的各向异性规律。结合实际工程应用, 提出正确引用RQD指标的建议。     

粮食作物产量估算方法研究

文章分析了我国自然植被净第一生产力的分布状况和粮食作物生物量的时空变化，以及自然植被净第一生产力与粮食作物生物量的关系，并在此基础上，提出一种我为粮食作物产量的估算的方法。     

祁连山青海云杉林辐射平衡研究

研究了青海云杉林的辐射平衡，表明青海云杉林冠辐射平衡各分量在总辐射中所占的比例为；反射辐射１２．０７％，净长波辐射２９．４６％，净全辐射５８．４７％，辐射平衡各分量与总辐射线性回归，相关紧密；青海云杉林林内总辐射林外减少７１．０２％，林内净辐射变幅小于林冠层。     

点源三维地形视电阻率的计算

利用格林公式及点源场的边界条件,将地下半空间位函数的体积积分变为地面位函教的积分方程以后,用边界元方法解此积分方程便可得到地面各节点的电位值。其计算精度和速度取决于剖分方式和节点密度。本文采用变网格的剖分方式,用较少的点实现了计算,并兼顾了精度和速度。     

一种基于自适应谐振理论的TM遥感影像神经网络分类器

提出了一种基于自适应谐振理论建立起来的自组织模糊ARTMAP神经网络分类器。分析了ART神经网络的结构和工作原理,给出模糊ARTMAP神经网络分类的具体算法,并将其运用到TM遥感影像分类的实验中。结果表明模糊ARTMAP神经网络分类器的速度快,精度高,比常用的BP网络具有更好的性能。     

基于跟踪站模式下的GPS技术应用

随着GPS卫星轨道精度的提高、数据处理模型和方法的完善、软件的可视化、仪器性能的改善与性价比的提高,GPS技术在我国得到了广泛应用与发展。在构建空间数据基础框架之际,全国各地正在建立或改造GPS网。针对经典建网方法,介绍了基于跟踪站模式下的GPS技术,并以实例对数据处理方案、观测时间的选取进行了分析和比较。     

成像光谱数据建模与分类识别技术研究——以云南腾冲矿区为试验区

在系统分析成像光谱数据特征及岩石矿物具有诊断意义的吸收光谱特征形成机理的基础上，采用基于相关系数测度的光谱匹配技术、基于高斯改进型模型的光谱建模技术及人工神经网络分类算法，实现了岩石矿物光谱特征波形对比分析及诊断光谱信息提取与建模，提高了光谱分类识别算法的计算速度和分类精度。采用上述技术对云南腾冲铀矿区进行实验研究，取得良好效果。     

GPS技术在煤矿区域测量控制网中的应用

介绍了GPS技术在煤矿区域测量控制网中的典型应用，就煤矿井田区域控制网的网型结构、高级控制点联测、野外观测时间、控制网精度分析等方面进行了阐述，并结合多年来本单位建立煤矿GPS控制网的生产实践，介绍了几点经验体会。     

Net water vapour exchange over a mixed needle and broad-leaved forest in Changbai Mountain during autumn

Water vapour and CO2 fluxes were measured by the eddy-covariance technique above a mixed needle and broad-leaved forest with affiliated meteorological measurements in Changbai Mountain as part of China's FLUX projects since late August in 2002. Net water vapour exchange and environmental control over the forest were examined from September 1 to October 31 in 2002. To quantify the seasonal dynamics, the transition period was separated into leafed, leaf falling and leafless stages according to the development of leaf area. The results showed that (a) seasonal variation of water vapour exchange was mainly controlled by net radiation (Rn) which could account for 78.5%, 63.4% and 56.6% for leafed, leaf falling and leafless stages, respectively, while other environmental factors' effects varied evidently; (b) magnitude of water vapour flux decreased remarkably during autumn and daily mean of water vapour exchange was 24.2 mg m-2 s-1 (100%), 14.8 mg m-2 s-1 (61.2%) and 10.3 mg m-2 s-1 (42.6%) for leafed, leaf falling and leafless stage, respectively; and (c) the budget of water vapour exchange during autumn was estimated to be 87.1 kg H2O m-2, with a mean of 1427.2 g H2O d-1 varying markedly from 3104.0 to 227.5 g H2O m-2 d-1.