GOCE�����ݶ������˲������������������   总被引：1，自引：0，他引：1  

杨洪国  黄强 《大地测量与地球动力学》2014,34(3):146-150

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Different units of measurement of carotenoids estimation in cotton using hyperspectral indices and partial least square regression     

《ISPRS Journal of Photogrammetry and Remote Sensing》2014

This paper examines the use of canopy reflectance for different units of measurements of carotenoids estimation. Field spectral measurements were collected over cotton in different intensive field campaigns organized during the growing seasons of 2010 and 2011. Three units of measurement were evaluated carotenoids expressed as a mass per unit soil surface area (g/m²), a mass per unit leaf area (μg/cm²), and a mass per unit fresh leaf weight (mg/g), respectively. Four methods were compared to retrieve amount of carotenoids: stepwise multiple linear regression (SMLR), published spectral indices, band combination indices, and partial least square regression (PLSR). Results show that maximum sensitivity of reflectance to variation in different units of measurement of carotenoids was found in the green region at 515–550 nm, and at 715 nm and 750 nm regions in the far-red wavelengths. The predictive accuracies of Car (g/m²), Car (μg/cm²) and Car (mg/g) were tested on a validation data set and the results show that the highest R² values between estimations and observations were 0.468 for Car (g/m²), 0.563 for Car (μg/cm²), and 0.456 for Car (mg/g), with relative root mean square error (RMSE%, RMSE/mean) of 48.72%, 22.07% and 21.07%, respectively. Compared to Car (g/m²) and Car (mg/g), the model performance indices for Car (μg/cm²) show a high degree of consistency among the R² values and RMSE% and MAE% values. Further comparison were performed among the estimation accuracies of different unit carotenoids and among the different approaches used in the study by a paired-t-test. The results indicate that although the best estimation results for Car (μg/cm²) and Car (mg/g) were both obtained based on PLSR, they can be estimated by all four adopted methods without significant differences (P > 0.1). Whereas for Car (g/m²), the best estimation results were obtained based on published vegetation indices CIred-edge, which were significantly better than the estimation results based on SMLR (P < 0.000). In summary, the results of this study show that even the carotenoids expressed on concentration (mg/g) or content (μg/cm²) basis at leaf level can be estimated with the same prediction accuracies to the carotenoids expressed as a mass per unit surface area (g/m²) at canopy level using reflectance measurement at canopy level.  相似文献   

L波段雷达系统不同测风方法计算结果分析     

罗雄光  梁国锋  杨超 《气象科技》2015,43(6):1025-1029

根据广东阳江探空站L波段雷达系统观测的测风资料分析,测风记录用综合探测雷达测风方法与无斜距（或高度替代）测风方法计算的测风量得风层的结果,少数情况下会出现与理论值不相符的现象,两种测风方法计算的结果,有时会超出高空气象观测仪器总体测量准确度要求允许的误差范围。在雷达的仰角小于30°时,量得风层的风速小于3 m/s时,两种测风方法计算量得风层的风速基本相同（误差在允许范围内）,但风向有的相差较大,超出测量准确度要求允许的误差范围。当雷达仰角小于15°,量得风层的风速大于30 m/s时,两种测风方法计算量得风层的风向比较接近,但量得风层的风速有的却相差较大,超出测量准确度要求允许的误差范围。  相似文献   

A differential optical absorption spectroscopy method for {X_{CO_2}} retrieval from ground-based Fourier transform spectrometers measurements of the direct solar beam     

Yanfeng Huo  Minzheng Duan  Wenshou Tian  Qilong Min 《大气科学进展》2015,32(8):1119-1128

A differential optical absorption spectroscopy (DOAS)-like algorithm is developed to retrieve the column-averaged dry-air mole fraction of carbon dioxide from ground-based hyper-spectral measurements of the direct solar beam. Different to the spectral fitting method, which minimizes the difference between the observed and simulated spectra, the ratios of multiple channel-pairs——one weak and one strong absorption channel——are used to retrieve X CO2 from measurements of the shortwave infrared (SWIR) band. Based on sensitivity tests, a super channel-pair is carefully selected to reduce the effects of solar lines, water vapor, air temperature, pressure, instrument noise, and frequency shift on retrieval errors. The new algorithm reduces computational cost and the retrievals are less sensitive to temperature and H2O uncertainty than the spectral fitting method. Multi-day Total Carbon Column Observing Network (TCCON) measurements under clear-sky conditions at two sites (Tsukuba and Bremen) are used to derive X CO2 for the algorithm evaluation and validation. The DOAS-like results agree very well with those of the TCCON algorithm after correction of an airmass-dependent bias.  相似文献   

奇异摄动系统的有限频段正实引理和界实引理     

梅平  付景枝  臧强 《南京气象学院学报》2013,5(5):397-401

利用GKYP引理研究了奇异摄动系统的有限频段正实引理和界实引理,证明了全阶系统的有限频段正实性可以由快、慢子系统的有限频段正实性得到,同样可以证明奇异摄动系统的有限频段界实引理具有类似性质.最后作为应用,给出了一个两频域尺度模型降阶实现方案,表明了该方法的有效性.  相似文献   

乌鲁木齐国际机场一次阵风锋天气成因分析     

张利平  王清平  陈阳权  朱国栋 《气象科技》2013,41(2):320-325

利用常规天气资料、跑道自动观测资料(AW0S)、自动气象站资料、卫星云图、多普勒天气雷达等资料,对乌鲁木齐机场发生的一次阵风锋造成的大风和沙暴天气进行分析.结果表明:①阵风锋天气来临时,具有气压陡升、温度骤降、风向变化、风速突增、湿度增加等气象要素的演变特征,跑道两端出现了风向和风速变化的不连续,多个时刻跑道水平风切变强度超过了强度标准值.②阵风锋天气是在500 hPa北支槽底分裂短波携带冷空气快速向东入侵渗透下出现的,大风沙暴发生在干线和地面风场辐合区附近,空中“干暖盖”的存在有利于不稳定能量的积累.③对流云团在东移过程中破坏了乌鲁木齐上空的逆温层,促使不稳定能量的释放,呼图壁至乌鲁木齐机场的大风沙暴天气就发生在TBB值梯度的密集带上.④阵风锋在雷达图中表现为强对流回波前方一条弱而窄呈南北向的带状回波,回波强度偏弱,速度场中形成了正负速度交界的辐合带.  相似文献   

Chan序贯平差组合算法的超宽带定位降噪     

董佳琪  连增增  徐精诚  魏峰远 《测绘通报》2023,(1):95-100+140

在室内环境中接收机与标签之间的距离会受到随机误差的影响,针对超宽带系统的定位特性,结合Chan算法和序贯平差算法的优势,本文提出了Chan序贯平差(Chan-SA)组合算法,以削弱测距随机误差的影响。首先,通过Chan算法两次加权最小二乘获得标签的三维坐标;然后,将此坐标作为初始值代入序贯平差算法中,利用序贯平差算法对后续数据进行迭代得出最优解。仿真数据和实地测量数据的解算结果表明：与Chan算法、粒子滤波算法和序贯平差算法比较,静态场景中Chan-SA算法定位精度分别提高50.14%、35.29%和41.91%,同时在动态场景内也证明了本文算法的适用性。因此,Chan-SA可以提高超宽带系统的定位精度和稳健性。  相似文献   

石鼓群的划分及变质特征探讨   总被引：1，自引：0，他引：1  

沙绍礼  陈晓林  贾昙 《云南地质》2014,(1):1-5,27

石鼓群位于云南西北部,面积约1 600km2,为甘孜一理塘板块的结晶基底.据现有资料,分为古元古代黎明岩群、中元古代新主岩群、新元古代巨甸岩群.黎明岩群为云母石英片岩、云母片岩,夹斜长片麻岩、斜长角闪岩.泥质岩石中具铁铝榴石、十字石、蓝晶石组合,基性岩中具铁铝榴石、普通角闪石组合,为中压低角闪岩相.黎明岩群后期抬升减压,叠加低压低角闪岩相变质,新生红柱石,部分原生蓝晶石退变成红柱石.于侵入其中的斜长角闪岩中获得Nd同位素模式年龄1 369.8Ma和1 343.8Ma,绿泥石英片岩中获得1 896.6Ma和2 161MaNd同位素模式年龄,故将黎明岩群时代置于古元古代.新主岩群分哈吉洛岩组和路西岩组,岩性为云母石英片岩、云母片岩、大理岩夹片麻岩及斜长角闪岩,部分岩石具糜棱岩化.哈吉洛岩组为低压低角闪岩相,具红柱石、十字石、铁铝榴石组合,路西岩组为高绿片岩相.于侵入新主岩群中的变质变形花岗质岩脉中获得锆石铅同位素年龄811 ±2Ma、820±1Ma、823±1Ma,故将新主岩群时代置于中元古代.巨甸岩群分陇巴岩组和塔城岩组,岩性为千枚岩、板岩,夹一层变质杏仁状玄武岩,为低绿片岩相.  相似文献   

贵州盘县煤炭矿区煤（层）的物性及煤质特征研究     

王秋菊  包立新 《云南地质》2014,(1):62-65

综合利用矿产资源现状调查工作成果,全面揭示盘县煤炭矿区已知煤（层）固有的物理化学特征,旨在总结煤炭资源的地质分布规律.区内含煤地层主要为二叠系龙潭组,煤的种类齐全,不同品质煤的分布较规律,煤炭矿区以低硫中挥发分为主,是主要的炼焦用煤和动力用煤,丰富的煤藏助力贵州经济发展.  相似文献   

个旧东区东西向断裂控岩控矿特征   总被引：1，自引：0，他引：1  

韩冬梅  谭敏 《云南地质》2014,(1):71-75

对东西向构造控岩控矿特征进行全面总结分析,讨论了东西向断裂深部找矿的意义,指出深部找矿方向.  相似文献