土壤墒情遥感反演与旱情诊断   总被引：1，自引：1，他引：0  

李玉环  王静  曹银贵 《地理科学进展》2006,25(2):123-130

土壤墒情与植被生长状况和地表温度之间存在密切联系?贑OST模型算法和单窗算法,开展了TM/ETM+多光谱数据的地表反射率、地表温度(LST)和土壤调整植被指数反演(MSAVI),分析了地表温度和植被指数的线性关系,提出了土壤墒情几何特征指数和旱情诊断函数,结合土壤含水量实测数据,建立了横山县土壤墒情遥感反演模型。实证结果表明,基于TM/ETM+数据反演的长度指数可进行旱情诊断;对土壤含水量的反演模型进行T检验,差异不显著,而基于地面温度的土壤墒情反演模型优于土壤调整植被指数反演模型。  相似文献   

周期-频度谱在小爆破自动识别研究中的应用   总被引：1，自引：1，他引：0  

张春贺  郑秀芬  许绍燮  梁建宏 《地震地磁观测与研究》2006,27(5):24-28

历年来在所开展小爆破识别与判据研究的基础上,进行了计算机易于实现爆炸事件自动识别判据的研究,通过对近震、爆破、矿塌和远震事件的周期-频度谱、波形不规则指数、卓越周期开展的研究,确定了切实可行的爆破事件自动识别方法和判据,达到了77%以上的正确自动识别概率。关键词爆破;自动识别;周期-频度谱;波形不规则指数;卓越周期  相似文献   

基于遥感视反射率图像的矿化信息识别及其应用   总被引：3，自引：0，他引：3  

王海平  张彤 《地球学报》2005,26(3):283-289

成矿作用过程中产生的矿化蚀变,在遥感图像上往往是一种非直接的弱相关信息。文章以川西西支沟地区为例,通过典型矿床地面波谱分析,并在视反射率图像模拟及其与典型矿床地面波谱反射率的相关分析基础上,对矿化蚀变信息进行反演识别研究。西支沟地区的研究表明,基于视反射率图像的矿化信息反演识别分析可增强遥感图像矿化信息,在多金属矿化信息识别方面有较理想的找矿预测效果。  相似文献   

Comparative study of otolith and sulcus morphology for stock discrimination of yellow drum along the Chinese coast     

SONG Junjie  ZHAO Bo  LIU Jinhu  CAO Liang  DOU Shuozeng 《海洋湖沼学报（英文）》2019,(4):1430-1439

Otolith morphology is widely used for fish stock identification. The sulcus, a structure on the medial side of the otolith, is an important feature in morphological analysis. This study was conducted to evaluate the feasibility of using sulcus morphology for stock identification and to compare its performance with commonly used otolith morphology analysis. Otoliths were collected and analyzed from three geographical groups (the Huanghe (Yellow) River estuary, HHE;the Jiaozhou Bay, JZB;and the Changjiang (Yangtze) River estuary, CJE) of yellow drum Nibea albiflora. The results show that the analysis of sulcus morphology based on shape indices (SIs), elliptic Fourier coefficients (EFc), and a combination of the two parameters identified stocks at overall classification rates of 51.0%, 72.5%, and 73.2%, respectively. These classification rates are similar to those obtained using otolith morphology analysis (57.0%, 73.8%, and 76.5% by SIs, EFc, and their combination, respectively). The findings suggest that sulcus morphology is comparable to the commonly used otolith morphology for identifying stocks of sciaenids, such as the yellow drum. For both otolith and sulcus morphology, EFc could identify the stocks more efficiently than SIs, while the combination of SIs and EFc was even better.  相似文献   

利用克里金技术标定新疆及附近地区P/S震相幅值比及其在地震事件识别中的应用   总被引：1，自引：1，他引：0       下载免费PDF全文

潘常周  靳平  肖卫国 《地震学报》2007,29(6):625-634

针对中国的乌鲁木齐台（WMQ）和哈萨克斯坦的马坎奇台（MAK）,采用贝叶斯克里金技术建立了新疆及附近地区地震事件的震相幅值比的校正曲面,并分析了校正曲面与地震波传播路径的关系,以及校正曲面对于改善震相幅值比判据识别效果的有效性.分析结果表明,建立的校正曲面基本合理,结合传播路径差异和地震波传播规律,能够较好地解释校正曲面的起伏特征. 而且,在传播路径差异较大,使得震相幅值比经震中距校正后离散度仍然较高的情况下,利用校正曲面修正震相幅值比,可以进一步降低其离散度,从而改善判据的识别效果.经校正曲面修正后,对天然地震的误识率由16.3%下降为5.2％.   相似文献   

Nitrogen isotopic discrimination by water column nitrification in a shallow coastal environment     

Ryo Sugimoto  Akihide Kasai  Toshihiro Miyajima  Kouichi Fujita 《Journal of Oceanography》2008,64(1):39-48

Temporal changes in nitrogen isotopic composition (δ¹⁵N) of the NO₃ ⁻ pool in the water column below the pycnocline in Ise Bay, Japan were investigated to evaluate the effect of nitrification on the change in the δ¹⁵N in the water column. The δ¹⁵N of NO₃ ⁻ in the lower layers varied from −8.5‰ in May to +8.4‰ in July in response to the development of seasonal hypoxia and conversion from NH₄ ⁺ to NO₃ ⁻. The significantly ¹⁵N-depleted NO₃ ⁻ in May most likely arose from nitrification in the water column. The calculated apparent isotopic discrimination for water column nitrification (ɛ_nit = δ¹⁵N_substrate − δ¹⁵N_product) was 24.5‰, which lies within the range of previous laboratory-based estimates. Though prominent deficits of NO₃ ⁻ from hypoxic bottom waters due to denitrification were revealed in July, the isotopic discrimination of denitrification in the sediments was low (ɛ_denit = ∼1‰). δ¹⁵N_NO3 in the hypoxic lower layer mainly reflects the isotopic effect of water column nitrification, given that water column nitrification is not directly linked with sedimentary denitrification and the effect of sedimentary denitrification on the change in δ¹⁵N_NO3 is relatively small.  相似文献   

特定折扣率的二度价格歧视研究     

方国敏 《成都信息工程学院学报》2008,23(4):460-463

研究基于垄断厂商收益最大化的特定折扣率的定价问题,给出解的具体表达式,同时解决原有文献中需求函数为非线性函数时,最优固定折扣率的解的问题。  相似文献   

鲁中地区分类强对流天气环境参量特征分析   总被引：13，自引：3，他引：10  

高晓梅  俞小鼎  王令军  王文波  王世杰  王新红  韩晓 《气象学报》2018,76(2):196-212

将山东中部地区16 a暖季(4-9月)106次伴随瞬时风力不低于8级的强对流个例划分为雷暴大风、冰雹雷暴大风和强降水混合型等3种类型,利用常规探空资料和地面观测资料,通过箱须图的形式分别讨论3种类型对应的一系列关键环境参数的分布特征和预报阈值。进一步,又将上述106次个例中的特强对流个例,包括产生25 m/s以上瞬时大风的特强雷暴大风个例、产生不小于20 mm直径冰雹的特强冰雹个例以及50 mm/h或以上强度的特强短时强降水个例提取出来构成一个子集,讨论其关键环境参数分布特征和预报阈值,并与全部对流个例的相应关键环境参数进行比较。最后,对鲁中地区强对流系统的触发机制进行了简要阐述和讨论。结果表明:(1)雷暴大风型、冰雹雷暴大风型和强降水混合型对应的850和500 hPa温差的最低阈值为25℃; 3种类型对应的地面露点最低阈值分别为13、16和24℃; 相应的大气可降水量最低阈值分别为20、24和32 mm; 相应对流有效位能的最低阈值分别为300、900和1300 J/kg; 相应的0-6 km风垂直切变最低阈值分别为12.0、12.5和8.0 m/s。(2)通过地面露点、大气可降水量以及暖云层厚度等关键参数的分布特征可以将上述3种类型的前两种与第3种类型即强降水混合型进行一定程度的区分,但要通过各个关键参数的分布特征区分前两种强对流天气是困难的。(3)对于伴随冰雹的强对流天气,适宜的融化层高度为3.0-3.9 km; (4)特强雷暴大风、特强冰雹和特强短时强降水等3种特强对流类型与全部强对流个例的3种类型相比,其条件不稳定度明显增大,体现为850和500 hPa温差的增大、水汽条件有所加强、对流有效位能明显增大,3种类型特强对流天气对应的对流有效位能最低阈值分别为1000、1100和2000 J/kg; 相应的0-6 km风垂直切变最低阈值分别为16、12和11 m/s,即特强雷暴大风型和特强短时强降水型的风垂直切变阈值明显增大。上述工作构成了山东中部伴随雷暴大风的强对流天气短时预报的一个基础,结合各类强对流天气发生的气候概率,可以通过决策树或模糊逻辑方法制作成适合于地、市气象台的分类强对流天气短时预报系统。   相似文献   

华池油田长3岩性油藏流动单元划分及其合理性验证     

朱玉双  柳益群  赵继勇  朱圣举  赵向宏  徐森 《沉积学报》2008,26(1):120-127

提出岩性油气藏流动单元划分及其合理性验证方法。研究中针对华池油田长3岩性油藏的特点,采取控制流体渗流的主要参数,对流动单元进行了划分。同时采用数学方法、微观渗流实验方法、宏观生产动态分析方法对流动单元划分的合理性进行了验证。研究结果表明:1）研究区流动单元可以分为三类,分别为A类、B类和C类。不同流动单元所处相带位置不同,物性也不同。
2）判别分析的方法、渗流实验方法和生产动态分析法是验证流动单元划分合理性的有效手段。研究区流动单元的正判率达95％以上;相同流动单元具有相似的微观渗流特征及生产动态特征,不同流动单元的微观渗流特征及生产动态特征明显不同。
3）C类流动单元及注采井间不同流动单元对接区域是剩余油的主要富集区,应注意挖潜,提高油层采收率。  相似文献   

Crop discrimination in Northern China with double cropping systems using Fourier analysis of time-series MODIS data   总被引：4，自引：0，他引：4  

Zhang Mingwei  Zhou Qingbo  Chen Zhongxin  Liu Jia  Zhou Yong  Cai Chongfa 《International Journal of Applied Earth Observation and Geoinformation》2008,10(4):476

Crop identification is the basis of crop monitoring using remote sensing. Remote sensing the extent and distribution of individual crop types has proven useful to a wide range of users, including policy-makers, farmers, and scientists. Northern China is not merely the political, economic, and cultural centre of China, but also an important base for grain production. Its main grains are wheat, maize, and cotton. By employing the Fourier analysis method, we studied crop planting patterns in the Northern China plain. Then, using time-series EOS-MODIS NDVI data, we extracted the key parameters to discriminate crop types. The results showed that the estimated area and the statistics were correlated well at the county-level. Furthermore, there was little difference between the crop area estimated by the MODIS data and the statistics at province-level. Our study shows that the method we designed is promising for use in regional spatial scale crop mapping in Northern China using the MODIS NDVI time-series.  相似文献