交互式数据语言在气象数据可视化中的应用          下载免费PDF全文

曾财兴  曹长尧 《气象科技》2007,35(B12):65-66,94

科学计算可视化是20世纪80年代后期随着计算机图形学应用的拓广而发展起来的一个新的研究分支，受其推动，数字信息的可视化成为20世纪90年代研究的前缘。随着“数字地球”、“数字城市”、“数字油田”等概念的提出，气象工作者迫切需要更加精确地了解各种气象数据和地形实体。而对于这些复杂的数据资料，目前人们已不能满足于等线图那样的平面描述，更需要建立三维图像，用更接近实际的方式去描述它，从各个不同角度观察它，三维可视化就是实现以上目标的有效手段。实体三维可视化技术是描绘和理解三维实体的一种重要计算机技术，它可以帮助使用者快速、准确理解和描述三维实体，并能协助快速选定感兴趣的目标，为分析、理解数据提供了有利工具。  相似文献   

雨涝灾害对舞钢市棉花生产的影响     

付世权  曹春田  臧学斌  朱柳松  王俊香  王丽英  王梅香 《河南气象》2007,(Z1)

通过田间调查,对2004-2006年棉花不同阶段雨涝情况对棉花生育及产量构成的影响进行了比较分析,并提出了相应的抗灾减灾对策。  相似文献   

GPS精密单点定位(静态)影响收敛速度的因素分析     

曹相  高成发 《现代测绘》2007,30(1):19-21

GPS精密单点定位是最近几年发展起来的一项GPS定位新技术,是目前GPS界研究的热点之一.本文简要介绍了GPS精密单点定位的原理,通过对实验数据的处理,计算出利用IGS分析中心提供的五种精密星历和卫星钟差进行单点定位所能达到的精度,又较为详细的分析了影响收敛速度的因素,得出COD的定位精度是最高的,其收敛速度也是最快的,另外减小对流层延迟和GDOP大小对提高收敛速度也是有效的方法.  相似文献   

Validating the Runoff from the PRECIS Model Using a Large-Scale Routing Model   总被引：4，自引：0，他引：4  

曹丽娟  董文杰  许吟隆  张勇 《大气科学进展》2007,24(5):855-862

The streamflow over the Yellow River basin is simulated using the PRECIS （Providing REgional Climates for Impacts Studies） regional climate model driven by 15-year （1979-1993） ECMWF reanalysis data as the initial and lateral boundary conditions and an off-line large-scale routing model （LRM）. The LRM uses physical catchment and river channel information and allows streamflow to be predicted for large continental rivers with a 1°×1° spatial resolution. The results show that the PRECIS model can reproduce the general southeast to northwest gradient distribution of the precipitation over the Yellow River basin, The PRECIS- LRM model combination has the capability to simulate the seasonal and annual streamflow over the Yellow River basin. The simulated streamflow is generally coincident with the naturalized streamflow both in timing and in magnitude.  相似文献   

Carbon isotopic composition of modern soil and paleosol as a response to vegetation change on the Chinese Loess Plateau   总被引：7，自引：0，他引：7  

LIU Weiguo  NING Youfeng  AN Zhisheng  WU Zhenghai  LU Huayu & CAO Yunning State Key Laboratory of Loess  Quaternary Geology  IEE  Chinese Academy of Sciences  Xi''''an  China Northwest Sci-Tech University of Agriculture  Forest  Yangling  China 《中国科学D辑(英文版)》2005,48(1):93-99

The relationship between the carbon isotopic composition of paleosols and pale-ovegetation on the Loess Plateau is still unclear. One of the main reasons is that we are short of knowledge about the characteristics of the carbon isotopic composition of modern soil in this area. A preliminary investigation of the carbon isotopic compositions of the modern soil and the loess/paleosol sequence on the Loess Plateau shows that the carbon isotopic composition of modern soil is consistent with the distribution of modern plants on the Loess Plateau, where the ecosystem is dominated by a mixture of C4 and C3 plants. Comparing the δ13C values of modern soil and loess-paleosol sequences from the Xunyi profile, we conclude that C3 plants dominated the landscape during loess sediment stages, while C4 plants expanded during paleosol stages.  相似文献   

Nitrogen isotopic geochemical characteristics of crude oils in several basins of China     

CHEN Chuanping    MEI Bowen & CAO Yacheng . Jianghan Petroleum University  Jingzhou  China  . Huazhong University of Science  Technology  Wuhan  China  . Nanjing Institute of Soil Science  Chinese Academy of Sciences  Nanjing  China 《中国科学D辑(英文版)》2005,48(8):1211-1219

Nitrogen occupies a high content in crust and in atmospheric circle. It is one of the main elements in organism and an important element in sedimentary circle. Although nitrogen is little in crude oil, to a cer-tain degree, it influences the physical and chemical properties of oil, such as viscosity and density[1]. In reservoir the nitrogen-bearing compounds can form ion bonds or hydrogen bonds with substances on rock and form van der Vaals’ force among moleculae so they affect and alter the …  相似文献   

Impacts of land-use and climate changes on ecosystem productivity and carbon cycle in the cropping-grazing transitional zone in China   总被引：4，自引：0，他引：4  

GAO Zhiqiang  LIU Jiyuan  CAO Mingkui  LI Kerang & TAO Bo Institute of Geographic Sciences  Natural Resources Research  Chinese Academy of Sciences  Beijing  China 《中国科学D辑(英文版)》2005,48(9):1479-1491

Terrestrial ecosystems are both a carbon source and sink, therefore play an important role in the global carbon cycle that act as a link of interactions between human activities and climate changes[1,2]. Climate change impacts ecosystem carbon cycle through af- fecting biological processes, e.g. plant photosynthesis, respiration, and soil carbon decomposition. Land-use change directly modifies the distribution and structure of terrestrial ecosystems and hence the carbon storage and fluxes. Usi…  相似文献   

Photometric studies of three Be stars     

Gao Wei-shi  Guo Xiao-zhen  Guo Yu-lian  Cao Hui-lai 《Chinese Astronomy and Astrophysics》1981,5(3):349-356

From 1978 December to 1979 May, we made spectrographic observations of φPer, ζTau and κDra using our Schmidt cassegrain grating spectrograph. Values of electron density, rotational speed and variation have been obtained and a comparison between ζTau and the supergiant βOri carried out. We found that, over our observed period, θPer showed clear shell activities, ζTau was in a relatively calm phase, its shell slowly expanding, while κDra had all the signs of a “classical” Be star.  相似文献   

Cross-correlation between WMAP and 2MASS: non-Gaussianity induced by the SZ effect     

Liang Cao  Yao-Quan Chu  Li-Zhi Fang 《Monthly notices of the Royal Astronomical Society》2006,369(2):645-654

We study the non-Gaussianity induced by the Sunyaev–Zel'dovich (SZ) effect in cosmic microwave background (CMB) fluctuation maps. If a CMB map is contaminated by the SZ effect of galaxies or galaxy clusters, the CMB maps should have similar non-Gaussian features to the galaxy and cluster fields. Using the WMAP data and 2MASS galaxy catalogue, we show that the non-Gaussianity of the 2MASS galaxies is imprinted on WMAP maps. The signature of non-Gaussianity can be seen with the fourth-order cross-correlation between the wavelet variables of the WMAP maps and 2MASS clusters. The intensity of the fourth-order non-Gaussian features is found to be consistent with the contamination of the SZ effect of 2MASS galaxies. We also show that this non-Gaussianity can not be seen by the high-order autocorrelation of the WMAP . This is because the SZ signals in the autocorrelations of the WMAP data generally are weaker than the WMAP –2MASS cross-correlations by a factor f ², which is the ratio between the powers of the SZ-effect map and the CMB fluctuations on the scale considered. Therefore, the ratio of high-order autocorrelations of CMB maps to cross-correlations of the CMB maps and galaxy field would be effective to constrain the powers of the SZ effect on various scales.  相似文献   

High-Spatial-Resolution Imaging Combining High-Order Adaptive Optics,Frame Selection,and Speckle Masking Reconstruction     

Carsten?DenkerEmail author  Dulce?Mascarinas  Yan?Xu  Wenda?Cao  Guo?Yang  Haimin?Wang  Philip?R.?Goode  Thomas?Rimmele 《Solar physics》2005,227(2):217-230

We present, for the first time, high-spatial-resolution observations combining high-order adaptive optics (AO), frame selection, and post-facto image correction via speckle masking. The data analysis is based on observations of solar active region NOAA 10486 taken with the Dunn Solar Telescope (DST) at the Sacramento Peak Observatory (SPO) of the National Solar Observatory (NSO) on 29 October 2003. The high Strehl ratio encountered in AO corrected short-exposure images provides highly improved signal-to-noise ratios leading to a superior recovery of the object’s Fourier phases. This allows reliable detection of small-scale solar features near the diffraction limit of the telescope. Speckle masking imaging provides access to high-order wavefront aberrations, which predominantly originate at high atmospheric layers and are only partially corrected by the AO system. In addition, the observations provided qualitative measures of the image correction away from the lock point of the AO system. We further present a brief inspection of the underlying imaging theory discussing the limitations and prospects of this multi-faceted image reconstruction approach in terms of the recovery of spatial information, photometric accuracy, and spectroscopic applications.The editors apologize to the authors: due to a misunderstanding during the editorial process, the publication of this paper has been delayed.  相似文献