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在卫星云图降水分析中,针对降水天气和降水强度具有明显的"模糊"特性,提出了云图降水的模糊推理模型.从不同云类降水的经验知识和降水天气的卫星云图样本中,提取出若干云类降水规则.在此基础上,引入模糊推理方法,建立了卫星云图降水分布和降水强度估计的模糊推理模型.实际应用中,对卫星云图进行云分类,根据云分类结果,去除不可能产生降水的云类区域.对可能产生降水的云类区域,通过提取多光谱云图的灰度等特征进行推理判别,进而得出该区域是否降水以及降水强度和降水分布的估算.试验结果表明,该方法在客观性、定量性和自动化程度方面优于传统的降水估计方法,且建模所需的样本少,可适用于多种类型的气象卫星云图. 相似文献
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利用2012年敦煌云图特征量资料和太阳总辐射逐小时观测资料,研究了敦煌太阳总辐射量与云量、红外亮温、大气可降水、可见光反射率等云图特征量的关系,发现敦煌地区太阳总辐射值的衰减值和总辐射理论值的日变化规律基本一致,敦煌站云图的云量、红外亮温、可见光反射率、大气可降水等特征量和太阳总辐射衰减率具有很好的相关性。进而将云图特征量作为预报因子,利用多元线性回归方程,建立太阳总辐射量统计预报模型。利用2012年敦煌云图特征量资料和太阳总辐射衰减率对方程进行预报效果检验。12个月太阳总辐射衰减率预测结果与实测值变化趋势基本一致,表明基于云图特征量的太阳辐射预报方法具有较好的应用前景。 相似文献
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本文利用数学建模思想,结合中国大陆地区的一个实例,给出了借助卫星云图直接推测降水量分布的一个简单方法。通过消除底图干扰,对一天内各时次的原始卫星云图进行叠加求平均等处理后,进行灰度线性变换和灰度级—彩色变换,分别得出表示降水分布的灰度图和彩图。将反演结果与地面观测资料进行比较,发现此方法比较适合中国北方和青藏高原地区,而在南方效果较差。 相似文献
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《科技资讯》2016,(18)
西南地区是我国西部山区大型滑坡灾害的主要发生地,因此西南地区的气象资料所映射出的信息对大型滑坡致灾因子的识别和预报预警方法的研究具有非常重要的意义。由于获取的大量原始气象资料的存储格式、观测时次疏密、分辨率等均存在差异,因而造成应用过程中的困难和局限,往往需要对实际观测的多源资料进行测试和预处理。(1)通过四川、重庆、云南和贵州4省市逐日常规气象观测资料的统计加工处理,获得了西南地区各时间尺度的降水趋势、地理分布以及各级别降水量的气候概率值。(2)由于西南地区地形复杂,局地小尺度的气象要素特征在常规气象观测资料中可能会被平滑或显示不明显,因此利用观测网格更为细致的逐小时区域自动站的资料就非常必要,利用收集的西南地区2 469个区域自动站资料分析了局地小尺度的气象要素分布及变化特点。(3)运用收集到的风云二号(FY2)卫星云图资料和反演的降水估计产品,进一步分析了西部地区尤其是西藏西北部资料空白区域的降水分布;卫星资料反演降水产品与实况降水对比相似率在60%以上,精度达到40%左右。(4)通过四川凉山州对流性降水案例的雷达图像资料的加工处理,分析了西南地区雷达回波资料在强降水天气及滑坡和泥石流灾害发生时的环境条件和临近预报预警的可行性。(5)利用发生在四川盆地边缘山地的两次降水过程进行WRF数值模式的敏感性试验和环流特征分析及动力特征等分析。模拟再现了降水的雨带走向、形状特征、雨区位置、暴雨中心位置以及中尺度辐合线、中尺度低涡等中尺度系统活动过程,表明WRF模式的敏感性和应用性。 相似文献
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"05.07.02"临汾局部大暴雨中尺度分析 总被引:2,自引:0,他引:2
本文论述了2005年7月2日临汾局部大暴雨降水过程特征,并对暴雨发生时的天气背景、主要影响系统、云图和雷达资料进行了分析,结果表明:这次大暴雨是在有利的天气背景下、副高北抬与西风槽结合、高低空急流耦合、700hPa主导系统低涡串西南东北上的条件下产生的;时效性强的卫星云图和雷达图是对天气图很好的补充. 相似文献
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由于青藏高原气象观测站较少,利用天气图作兰州地区降水预报有困难。本文利用卫星云图统计资料,通过对云图中水汽输送路径及其与兰州地区降水出现概率之间关系的分析,做出兰州地区降水预报。 相似文献
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Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness. 相似文献
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Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly. 相似文献
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Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well. 相似文献
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The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation. 相似文献
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理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。 相似文献
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As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death. 相似文献
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Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system. 相似文献
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Miao Maosheng 《华南师范大学学报(自然科学版)》2014,(6)
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula- 相似文献
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Yang Weitao 《华南师范大学学报(自然科学版)》2014,46(6):137-138
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re- 相似文献
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Bernard Kirtman 《华南师范大学学报(自然科学版)》2014,(6)
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that 相似文献