青藏高原云-辐射-加热效应和南亚夏季风--1985年与1987年对比分析

文中首先利用NCEP NCAR再分析的风场资料 ,分析了南亚夏季风的时空特征 ,选取了有代表性的典型强、弱夏季风年 ,继而利用ISCCP C2、ERBE S4卫星观测资料和NCEP NCAR再分析资料 ,对比分析了强、弱夏季风前期青藏高原地区的云—辐射—加热状况及其在海、陆差异中的作用。分析结果表明 ,南亚夏季风强或弱 ,其前期青藏高原地区的云—辐射—加热效应有明显的差异。在强 (弱 )南亚夏季风的前期 ,青藏高原大部分地区为相对少 (多 )云区 ,其云量变化不仅表明了此区的云—辐射—加热效应的不同 ,更重要的是与此同时出现的海、陆之间云量分布的“跷跷板”现象 ,进一步改变了海、陆之间的热力差异。而且 ,在强南亚夏季风年 ,这种热力差异不但开始得早 ,而且持续时间长、作用范围大 ,从而对南亚夏季风的形成和变化产生重要的影响     

ARTIFICIAL NEURAL NETWORK CORRECTION OF ROUGH ERRORS OF OBSERVATIONS

In the context of tower measured radiation datasets.following the correction principle meetinga diagnostic equation in data quality control and in terms of a technique for model construction ondata and ANN(artificial neural network)retrieval for BP correction of radiation measurementswith rough errors available,a BP model is presented.Evidence suggests that the developed modelworks well and is superior to a convenient multivariate linear regression model,indicating its wideapplications.     

PRELIMINARY NUMERICAL STUDY OF TOPOGRAPHIC EFFECTS OF THE TIBETAN PLATEAU ON SURFACE DIRECT RADIATION*

To improve the simulating ability of a model,this paper presents a scheme of calculating direct radiation at land surface with topography in the model.A numerical study is conducted for the topographic effects of the Tibetan Plateau on the direct radiation using NCEP terrain data.Results show that,after taking account into the topographic radiation effect,the regional average of the radiation over the Plateau obviously increases in the local early morning and late afternoon,but changes less around noon.The effect is stronger in winter than that in summer.And heterogeneous topography has also affected the distribution of the radiation in this area.A simple numerical experiment shows that considering the effect will lead ground temperature to increase on the slope having more sunshine,and vice versa.     

ARTIFICIAL NEURAL NETWORK CORRECTION OF ROUGH ERRORS OF OBSERVATIONS*

In the context of tower measured radiation datasets.following the correction principle meeting a diagnostic equation in data quality control and in terms of a technique for model construction on data and ANN (artificial neural network) retrieval for BP correction of radiation measurements with rough errors available,a BP model is presented.Evidence suggests that the developed model works well and is superior to a convenient multivariate linear regression model,indicating its wide applications.     

PRELIMINARY NUMERICAL STUDY OF TOPOGRAPHIC EFFECTS OF THE TIBETAN PLATEAU ON SURFACE DIRECT RADIATION

To improve the simulating ability of a model,this paper presents a scheme of calculatingdirect radiation at land surface with topography in the model.A numerical study is conducted forthe topographic effects of the Tibetan Plateau on the direct radiation using NCEP terrain data.Results show that,after taking account into the topographic radiation effect,the regional averageof the radiation over the Plateau obviously increases in the local early morning and late afternoon,but changes less around noon.The effect is stronger in winter than that in summer.Andheterogeneous topography has also affected the distribution of the radiation in this area.A simplenumerical experiment shows that considering the effect will lead ground temperature to increase onthe slope having more sunshine,and vice versa.     

基于DEM的黄河流域天文辐射空间分布

基于1 km×1 km分辨率的数字高程模型(DEM) 数据,利用建立的起伏地形下天文辐射分布式计算模型,计算了黄河流域1 km×1 km分辨率各月天文辐射的空间分布。结果表明:局部地形对黄河流域年和四季天文辐射的空间分布影响明显;在太阳高度角较低的冬季,地理和地形因子对天文辐射的影响相当强烈,山区天文辐射的空间差异大,1月份向阳山坡(偏南坡) 天文辐射可为背阴山坡(偏北坡) 的2~3倍,极端天文辐射的差异可达10倍以上;而在太阳高度角较高的夏季,天文辐射空间差异较小,7月份不同地形极端天文辐射的差异仅在16%左右;四季中,地形对天文辐射影响的程度为冬季>秋季>春季>夏季。     

青海平安电磁辐射在中强震前短期前兆异常特征及预报效能研究

分析和整理了青海平安电磁辐射台自1993年7月以来的资料，发现震前平安单台电磁辐射在中强地震临震前有最大脉冲信号，并通过对无震异常，地震异常的分析判断，对其预报效能进行了R值评价。     

德令哈6．6级地震前卫星红外长波辐射OLR的分析

应用NOAA卫星资料反演的地震长波辐射值OLR对2003年4月17日发生在青海省德令哈西的6．6级地震进行了追踪研究。结果显示：2003年1月起OLR距平值出现明显的高值异常区域。     

基于资源卫星图像对NDVI进行大气修正的一种简单方法

在遥感应用领域，植被指数己被广泛用来定性和定量表征植被覆盖度及其生长状况。由于大气变化的影响，使植被指数未能真实反映地表植被的真实分布状况，造成其应用的局限性。提出了一种简易方法，仅通过中巴资源卫星(CBERS：China Brazil Environment Resoure Satellite)图像的第3、第4波段中的水体，推算卫星接收到的大气程辐射，消除了大气对归一化植被指数(NDVI：Normalized Differece Vege—tation Index)的影响，减小植被指数所受的大气影响。应用结果表明，该方法能使植被指数较好地反映植被的生长及分布状况。     

自然与农田状态下照度计测光的偏差分析

根据色度基本原理，推导并计算了不同天气类型下照度的换算因数，并在不同天气类型下，对自然光和小麦群体不同高度透光情况进行了测定，将照度计实测照度换算出的辐射强度与实测辐射强度进行对比。结果表明：①前两种照度计可以在1、2级日光状况下用于太阳辐射测定而在3、4级日光状况下误差较大。②在作物田中，实测照度换算为辐射光量子数时，内活动面偏差比在0.2左右，而外活动面因光斑阴影作用，偏差较大，实测时应增加重复。