2004年广东省干旱灾害遥感监测应用研究

针对广东省气候湿润、植被覆盖度高的特点,以NOAA/AVHRR资料为数据源,采用植被供水指数法,对2004年广东省发生的50年来最严重的一次干旱灾害进行遥感动态监测,并结合土地利用分类数据,采用掩膜技术提取干旱分类信息.研究结果表明,10月上旬全省部分地区出现旱情,10月下旬全省受旱总面积达到峰值,占全省面积的72.6%;11月上旬后期受旱面积有所减少,中旱、重旱区域有所增加,其后旱情总体呈减缓趋势,但在12月中旬出现了短暂的增加趋势.以11月上旬为例的干旱灾害分类研究还表明,水田、旱地、灌木、林地等不同的用地类型,其受旱比例依次递减.该研究结果较好地反映了本次干旱灾害的空间分布及发展过程,为相关部门进行干旱灾情评估、制定和实施抗旱减灾措施提供了科学依据.     

统计预测方法的试验比较

通过相关系数选出预报因子,用逐步回归、最优子集回归、EOF降维逐步回归、神经网络等统计预报方法对预报对象进行逐年交叉检验以及实际预报检验,检测预报因子对原预报序列的预报能力。同时通过计算每种方法的平均绝对误差和实际预报检验的平均误差,客观地对各种预报方法进行既有纵向也有横向的较为全面的比较。     

FEATURES OF WATER VAPOR TRANSPORT OF TYPHOON DAN (9914)

The 2.5^。×2.52^。 gridded ECMWF reanalysis data are used to diagnose the genesis, development and dissipation of typhoon Dan by calculated stream function, velocity potential and vapor budget. It is shown in the result that when typhoon Dan moved westwards, water vapor mainly came from the eastern and western boundaries, with most of it was transferred by the easterly flow south of the western North Pacific subtropical high; after Dan swerved northwards, water vapor mainly came from western boundary of the typhoon, and the vapor came from the South China Sea and the Indian Ocean. The transfer of water vapor was mainly concentrated on the mid-lower troposphere, especially the level of 925hPa, at which the most intensive transfer belt was located. During the different period of typhoon Dan, there was great water vapor change as indicated by stream function, velocity potential and vapor budget, which suggest the importance of water vapor in the development of typhoon Dan.     

基于植被-土壤二向反射模型的土壤含水量遥感

以北京地区为例，利用像元信息分解法，定量提取出区域植被盖度，由植被盖度得到区域叶面积指数，在只考虑一次散射的情况下，利用植被-土壤二向反射模型，提取出下层湿润土壤反射率。通过引入粗糙度因子建立起粗糙地表下土壤反射率与叶面积指数的函数关系，进而得出土壤含水量。     

CHANNEL SHRINKAGE AND ITS INSTABILITY IN THE LOWER YELLOW RIVER1

From the mid 1980s through the late 1990s, the channel of the lower Yellow River experienced serious shrinkage, which has decreased the flood conveyance of the channel and the sediment carrying capacity of the flow, raised the water levels of floods, and, thus, severely threatened the safety of flood control along the river. The completion of Xiaolangdi Dam in 1999 could help mitigate the channel shrinkage problem, but the situation has not changed yet. This paper analyses the characteristics, mechanisms, and conditions resulting in channel shrinkage, points out channel instabilities, and puts forward approaches of channel rehabilitation.     

No apparent lock-in depth of the Laschamp geomagnetic excursion: Evidence from the Malan loess

Developing an accurate chronological framework is always a key issue in paleoclimatic studies. Magneto- stratigraphy has been a routine tool for such purposes. However, complexities arise for inter-profile correla- tions of magnetostratigraphy due to effects of the lock-in process. One good example is the “mystery” of the mismatching of stratigraphic locations of the Matuyama/Brunhes boundary (MBB) (occurred at ~780 ka) recorded in Chinese loess and marine sedi- ments. Tauxe et al.[1] con…     

东天山哈密地区赤湖钼铜矿区斜长花岗斑岩锆石SHRIMP U-Pb年龄

东天山赤湖斑岩钼铜矿床的形成时代和成矿地质背景至今尚存在争议,前人根据同一成矿带中土屋-延东斑岩铜矿的同位素地质年龄信息,认为赤湖钼矿的形成时代为中-晚泥盆世,系塔里木板块北部活动陆缘泥盆纪岛弧火山-深成作用的产物;近期一些研究者根据赤湖斑岩钼铜矿区斜长花岗斑岩锆石U-Pb和谐曲线年龄,认为矿化斜长花岗斑岩的侵位时代为晚石炭世,成矿作用与哈萨克斯坦-准噶尔板块南部活动陆缘晚石炭世汇聚阶段钙碱性岩浆侵入作用有关.在前人研究基础上,笔者对赤湖斑岩钼铜矿区矿化斜长花岗斑岩体进行了锆石SHRIMP U-Pb定年研究,获得322Ma±10Ma(95%可信度)的年龄值,表明赤湖斑岩铜矿床的形成时代为晚石炭世,成矿作用与晚石炭世钙碱性岩浆浅成侵位有关.     

大型现场室内两用直剪仪研制（Ⅱ）：试验测试

利用新近研制的大型现场室内两用直剪仪，对两种不同性质的砂样进行了剪切试验。在对干砂的直接剪切试验特性进行综述的基础上，从多方面对该大型直剪仪得出的干砂剪切试验数据进行了分析验证，结果表明该大型直剪仪得出的试验数据一致性好、可靠性较高，说明该大型直剪仪的基本剪切性能稳定，可进一步应用于相关岩土材料的试验研究。     

多暗像元大气校正方法

 针对Landsat TM影像，设计了一种适用于非均质大气的大气校正方法。该方法以暗目标减法（DOS）为基础，结合大气辐射传输模型，通过选取TM影像上多个暗像元，并计算其所对应的大气校正系数对整幅图像进行大气校正。该方法不依赖任何外部信息，并且考虑了大气的非均质性，校正精度较高。     

废旧放射源的检测方法及其应用

根据地勘行业所用放射源的特点，确定了废旧放射源的种类、活度、表面剂量率和表面污染率等参数的检测方法，并将方法应用于对上百个未知放射源进行检测和档案整理，效果较好。