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1.
基于EMD方法的观测数据信息提取与预测研究 总被引：5，自引：1，他引：4
用统计方法作月、季尺度的短期气候乃至年际尺度的长期气候预测是当前气候预测业务的主要依据,在短时间内这种情况仍然不可能彻底改变。虽然数值预报模式的预测能力达到了7 d的时效,不过要积分到月、季尺度并实现短期气候预测还面临着重重困难。其根本原因是气候系统的混沌分量和非线性/非平稳性等因素在起作用。而现有气候预测的统计方法(主要包括经验统计、数理统计和物理统计等方法)的数学基础却忽略了这些特点,这是因为以现有的科学水平人们不得不假设时间序列是线性和平稳的。实际气候观测序列普遍具有层次性、非线性和非平稳性,这给建立预测方法带来了极大困难。文中构建了一个新的预测模型,即首先利用经验模态分解(em-pirical mode decomposition,EMD)方法将气候序列作平稳化处理,得到一系列平稳分量-本征模函数(intrinsic modefunction,IMF);其次,利用均生函数(mean generate function,MGF)模型获得各分量的初次预测值;最后,在最优子集回归(optimal subset regression,OSR)模型的基础上,通过直接或逐步拟合一部分预测值,构建两种预测方案达到提高预测能力的目的。典型气候序列的预测试验结果表明,具有平稳化的IMF分量,尤其是特征IMF分量有较高的可预测性,它对原序列趋势的预测有重要指示意义。大力开展气候系统机理和气候层次的研究,并建立相应的气候模式是未来发展趋势。该文是这方面的一个初步尝试,相信该模型能为气候预测(评估)开辟一条新的有效途径。 相似文献
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近年来,随着人工智能技术在多个领域大数据分析中的应用,许多研究工作者尝试将地学研究与人工智能跨学科结合,取得了很多新的进展,推动了地球科学的发展。其中气候预测与人类生活以及防灾减灾等息息相关,准确的气候预测至关重要。本文简要总结了人工智能技术在气候预测应用方面的研究进展,包括资料同化、模式参数化、求解偏微分方程、构建统计预测模型、改进数值模式产品释用等领域。这些研究证明了利用人工智能提高气候预测技巧的可能性和适用性,可以极大地节省计算成本和时间。然而人工智能应用也存在诸多挑战,例如数据集的构建、模型的适用性和物理可解释性等问题,对这些难点问题的研究和攻克,可以让人工智能在大数据时代中更好地补充传统地球科学方法,产生更多有益的效应,极大地改进气候预测水平。 相似文献
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《干旱气象》2015,(5)
采用集合经验模态分解(EEMD)和滑动傅里叶分析方法,建立了非线性气候序列的统计预测模型。针对气候要素距平场,对EOF分解得到的各模态时间系数进行EEMD分解,对得到的各IMF分量构建滑动傅里叶(Fourier)分析预报模型,提取出控制当前复杂气候信号的主要傅里叶频谱组合作为IMF分量的主要成分,即确定当前信号的主要波内频率,再将各个IMF分量和剩余项预测结果重构得到各模态时间序列的预测结果,最终通过时空重构得到预测场。将上述思想方法应用于新疆地区风场的预测试验,并采用距平相关系数(ACC),预报技巧(SS)和同号率(R)进行评估,结果表明对于区域性的风速预报,基于上述思想的算法模型能够较好地把握当前气候信号的主要变化频率,较为理想地预测了气候要素时间系数,对新疆地区风速变化的形态分布有较好的估计,使其预报时效在40侯以内均拥有一定的预报技巧,平均SS在0.5以上,36侯以内平均ACC达到0.4以上。 相似文献
4.
气候系统具有非平稳特征,根本原因在于其外强迫随时间发生改变,因此外部驱动力的分析对于理解气候系统的动力学特征至关重要,而如何有效提取系统外部驱动信息是一个亟待解决的前沿科学问题。最近几年,在生物神经学领域中应用的一种提取非平稳信号中外强迫信息的方法——慢特征分析法(Slow Feature Analysis,SFA),在气象领域中也得到了初步成功的尝试,结果显示出此方法对气候系统的外强迫信息分析及有关动力学机制的探究有较好的应用前景。本文主要介绍SFA方法的理论思想及实施步骤,并通过一个理想的非平稳时间序列检验其提取外强迫信息的能力,结果证明在衰减的Logistic模型中,可利用SFA算法提取出模型中的外强迫,且与真实外强迫的相关系数可达0.99;此外,还介绍将该方法应用于Arosa臭氧时间序列,分析其提取的外强迫信息的动力学特征;并介绍了在气候时间序列建模中引入外强迫因子的预测效果。 相似文献
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气象要素时间序列的演化建模分析与短期气候预测 总被引：3，自引：2，他引：1
以武汉站(5~9月)汛期降水量观测数据序列为例,将这类具有明显的不规则性(混沌特征)时间序列分解为宏观气候尺度周期的波动部分和迭加其上的微观气候尺度周期的波动部分,分别采用演化建模方法和自然基小波方法模拟逼近。特别强调由演化建模方法得到的非线性常微分方程较之传统的线性建模具有更好的分析预测能力。 相似文献
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郭骏 《沙漠与绿洲气象(新疆气象)》1987,(5)
一、引言近年来,时间序列方法有了很大的发展,由于车贝雪夫多项式既有标准图形又可用于不规则格点,因此在气候分析和天气预报中得到了广泛的应用.人们一般以展开高度场或要素场求车贝雪夫系数进行气候分析,再经过其它统计方法做预报.本文直接用车贝雪夫多项式展开要素序列进行外延预报,取得了比较满意的效果. 相似文献
10.
利用33模Lorenz系统得到的"理想"混沌时空序列,作为时空混沌序列"发生器".通过状态空间重构,建立"场时间序列"局域近似预测模型,对资料空间分辨率,资料的长度、噪音,以及模型的参数选取等因素进行敏感性试验分析,了解时空混沌序列预测中误差产生和增长的一些影响因素.得到以下初步结论:对于理想混沌时空序列(33模Lorenz系统)而言,与系统相适应的资料空间分辨率和较长的资料长度都将会提高预测精度;可预报时效与资料长度之间近似服从指数关系.另外,在建立预测模型时,适当的邻近点数目,以及采用二阶映射关系和迭代法都可以有效地改善预测精度.对于加入噪音的混沌时间序列,通过"场时间序列"的局域近似方法和4阶自回归方法的预测试验的对比表明,前者显示了更强的抗"干扰"能力.以上结论可以有分析地应用于短期气候预测中. 相似文献
11.
国家气象信息中心(NMIC)和美国大气海洋局气候预测中心合作开发了"中国逐日格点降水量实时分析系统(V1.0)",并已在NMIC投入业务试运行。该系统基于我国2419个国家级地面气象站日降水量观测(08:00—08:00,北京时)数据,采用"基于气候背景场"的最优插值方法,实时生成空间分辨率为0.5°×0.5°的格点化日降水量资料。通过对汛期典型区域和单站降水过程的对比分析表明:该格点化产品的精度较高,能准确捕捉并再现每一次降水过程。误差分析表明:约91%的数据绝对误差小于1.0 mm/d。该产品在定量分析天气实况、检验天气气候模式精度、检验卫星产品精度等方面有应用前景。 相似文献
12.
Umberto Triacca Antonello Pasini Alessandro Attanasio 《Theoretical and Applied Climatology》2014,118(3):491-495
Studies on persistence are important for the clarification of statistical properties of the analyzed time series and for understanding the dynamics of the systems which create these series. In climatology, the analysis of the autocorrelation function has been the main tool to investigate the persistence of a time series. In this paper, we propose to use a more sophisticated econometric instrument. Using this tool, we obtain an estimate of the persistence in global land and ocean and hemispheric temperature time series. 相似文献
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近年来中国统计气象学的新进展 总被引：17，自引：5，他引：17
近年来，统计气象学在中国取得了长足的进展。其中主要有：将熵原理用于气象学，从而建立了熵气象学；引进了忆及过去时次资料的记忆函数，导出了大气运动的自忆性方程；将模糊数学引入气象学；将非线性动力学用于气候学研究，提出了一系列相空间预报模式；将车贝雪夫多项式推广到不规则格点，提出了一种新的时间序列预报的迭代算法；应用子波分析方法进行气候学研究；将Ｌｏｇｉｓｔｉｃ判别分析用于气象预报，研究了二次判别及逐步判别等问题；将中国科学家提出的灰色系统理论和多层递阶方法引入气象预报。此外，还引进了复经验正交分解、奇异值分解、投影追踪、主振荡模态分析等较新的统计学方法。这些方法都已在气象业务预报中发挥了作用 相似文献
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Great advances in statistical meteorology have been made in recent years in China.The mainpoints are as follows:Introducing entropy principle into meteorology,entropy meteorology isfounded;Introducing memory function,self-memorization equation of atmospheric motion isderived;The fuzzy reasoning is introduced into meteorology;Using the method of nonlineardynamics in researches of climatology,some forecasting schemes of phase space are proposed;Chebyshev polynomial is generalized at irregular grids and an iterative scheme for forecast of timeseries is proposed:The wavelet transform is used in researches in climatology;Logisticdiscrimination is used in meteorology and quadratic discrimination and stepwise discrimination areinvestigated;The theory on grey system and the multilevel recursion proposed by Chinesescientists are introduced into meteorological forecast.In addition,complex empirical orthogonalfunction,singular value decomposition,projection pursuit,principal oscillation patterns and so onare also introduced.All the above methods have played great roles in operational weatherforecasts. 相似文献
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Rudolf Brázdil Petr Dobrovolný Jürg Luterbacher Anders Moberg Christian Pfister Dennis Wheeler Eduardo Zorita 《Climatic change》2010,101(1-2):7-40
Temperature reconstructions from Europe for the past 500 years based on documentary and instrumental data are analysed. First, the basic documentary data sources, including information about climate and weather-related extremes, are described. Then, the standard palaeoclimatological reconstruction method adopted here is discussed with a particular application to temperature reconstructions from documentary-based proxy data. The focus is on two new reconstructions; January–April mean temperatures for Stockholm (1502–2008), based on a combination of data for the sailing season in the Stockholm harbour and instrumental temperature measurements, and monthly Central European temperature (CEuT) series (1500–2007) based on documentary-derived temperature indices of the Czech Republic, Germany and Switzerland combined with instrumental records from the same countries. The two series, both of which are individually discussed in greater detail in subsequent papers in this special edition, are here compared and analysed using running correlations and wavelet analysis. While the Stockholm series shows a pronounced low-frequency component, the CEuT series indicates much weaker low-frequency variations. Both series are analysed with respect to three different long-period reconstructions of the North Atlantic Oscillation (NAO) and are compared with other European temperature reconstructions based on tree-rings, wine-harvest data and various climate multiproxies. Correlation coefficients between individual proxy-based series show weaker correlations compared to the instrumental data. There are also indications of temporally varying temperature cross-correlations between different areas of Europe. The two temperature reconstructions have also been compared to geographically corresponding temperature output from simulations with global and regional climate models for the past few centuries. The findings are twofold: on the one hand, the analysis reinforces the hypothesis that the index-data based CEuT reconstruction may not appropriately reflect the centennial scale variations. On the other hand, it is possible that climate models may underestimate regional decadal variability. By way of a conclusion, the results are discussed from a broader point of view and attention is drawn to some new challenges for future investigations in the historical climatology in Europe. 相似文献
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Marine surface temperature: Observed variations and data requirements 总被引：16，自引：0，他引：16
Measurements of temperature at the ocean surface are an indispensible part of the Global Climate Observing System (GCOS). We describe the varying coverage of these measurements from the mid-nineteenth century through to the present era of satellite data, along with ongoing attempts to augment the available digitized data base. We next survey attempts to remove systematic biases from both sea surface temperature (SST) and marine air temperature (MAT) data and to combinein situ and satellite SSTs in a consistent manner. We also describe new or planned geographically complete climatologies of SST and night MAT for 1961-90. These are expected to be more reliable than existing climatologies in the Southern Ocean and other sparsely-observed areas. The new SST climatology has been used in the construction of an improved geographically-complete data set of sea ice and SST: the techniques used are briefly reviewed, as are other methods of analysis and assessment of worldwide SST.We present global and regional time series of anomalies (i.e. deviations from reference climatology) of SST and night MAT for 1856 to 1994 constructed using the most complete data and best-estimate bias-corrections hitherto available. These series are compared with earlier published series, and are validated by means of comparisons with anomalies of air temperature from coastal and island stations. The sensitivity of the time series to imperfect coverage is assessed by means of frozen grid experiments. The results underscore the need for ongoing development of SST and MAT data bases within GCOS for the detection of climatic change, and for improved methods of analysis to optimally isolate the signals from incomplete data.The British Crown right to retain a non-exclusive royalty-free license in and to any copyright is acknowledged. 相似文献
17.
The paper analyzes equivalent data for a low density meteorological station network (spatially discontinuous data) and poor temporal homogeneity of thunderstorm observational data. Due to that, a Regional Climate Model (RegCM) dataset was tested. The Most Unstable Convective Available Potential Energy index value (MUCAPE) above the 200 J kg?1 threshold was selected as a predictor describing favorable conditions for the occurrence of thunderstorms. The quality of the dataset was examined through a comparison between model results and soundings from several aerological stations in Central Europe. Good, statistically significant (0.05 significance level) results were obtained through correlation analysis; the value of Pearson’s correlation coefficient was above 0.8 in every single case. Then, using methods associated with gridded climatology, data series for 44 weather stations were derived and an analysis of correlation between RegCM modeled data and in situ thunderstorm observations was conducted with coefficients in the range of 0.75–0.90. The possibility of employing the dataset in thunderstorm climatology analysis was checked via a few examples by mapping monthly, seasonal, and annual means. Moreover, long-term variability and trend analysis along with modeled MUCAPE data were tested. As a result, the RegCM modeled MUCAPE gridded dataset was proposed as an easily available, suitable, and valuable predictor for thunderstorm climatology analysis and mapping. Finally, some limitations are discussed and recommendations for further improvements are given. 相似文献
18.
在介绍相空间重构理论的基础上, 以攀西地区4个站点47 a的月降水时间序列为例, 研究了该地月降水时间序列的非线性特性。首先, 运用定量的G-P关联维方法, 探讨了非线性分析的主要定量指标, 具体而言有, 饱和关联维数D2和柯尔莫哥诺夫熵, 计算表明攀西月降水时间序列具有一定的非线性混沌特性。其次, 结合定性的功率谱分析方法, 进一步验证了攀西月降水时序具有非线性特性。除此之外还应用Cao方法检验, 从而排除了月降水时序为随机序列的可能性。本文为进一步研究月降水时序数据的复杂性及其演化规律奠定了基础。 相似文献
19.
Andrew R. Solow 《Climatic change》1999,42(1):341-349
A common problem in climatology is detecting a change in the frequency or magnitude of extreme events in an historical time series. This paper compares the performance of two general approaches to this problem in a simple situation. The first approach is based on modelling the entire distribution, while the second approach focuses on the tail of the distribution. Although the second approach has clear advantages, the results of this paper suggest that it can also involve a substantial loss of information. 相似文献
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Abstract The climatology of the Canadian Climate Centre atmospheric general circulation model is presented and compared with the observed climatology of the atmosphere. The model climatology is obtained from a simulation over five annual cycles and the results are presented in terms of averages for the four seasons. The climatology of the model is discussed in terms of zonally and time averaged values of the primary atmospheric variables as well as in terms of the spatial distributions of the important surface parameters and of the rotational and divergent components of the tropospheric flow. Some measure of model variability is also presented. The model is generally quite successful in reproducing the mean observed climatology of the atmosphere. 相似文献