广西春播期降水量预报方法研究

对广西春播期降水量序列利用３种时间序列分析法,通过相关系数与符号相关结合选取因子,建立了６种回归方程,试报结果表明：多因子场序相关相拟法有较可信的结果;在逐步回归预测方法中,多因子逐步回归优于单因子场逐步回归;集成预报的结果明显好于单一方法的结果。而在组合计算预报因子中,用５００ｈＰａ高度场、海平面气正场的滑动块状平均场作为基本因子,不仅符合降水发生所应具有的天气形势的系统性和稳定性,给自动化编程     

主分量逐步回归法在桂东南低温阴雨预报的应用

在桂东南低温阴雨天气的特征和类型研究的基础上,应用气候场的主分量逐步回归方法,通过多个气候场的主分量因子相关分析筛选,求得低温阴雨场主分量与高度场、海温场、环流指数以及副高面积指数等因子场主分量之间的联系,而后进行逐步回归预报.     

主分量逐步回归法在桂东南低温阴雨预报的应用

在桂东南低温阴雨天气的特征和类型研究的基础上，应用气候场的主分量逐步回归方法，通过多个气候场的主分量因子相关分析筛选，求得低温阴雨场主分量与高度场、海温场、环流指数以及副高面积指数等因子场主分量之间的联系，而后进行逐步回归预报。     

基于均生函数的EOF迭代温度长期预报

本文用单站温度时间序列的均生函数周期延拓序列拓展预报因子,然后进行EOF迭代温度预报试验,并与主分量、逐步回归筛选方案建模法的预报结果进行比较,初步表明:这种预报方法充分地利用了要素序列与其优势周期的主要相关信息,它具有一定的预报能力。     

前期高度场和海温场变化对我国汛期降水的影响

利用1952～2001年我国160个测站汛期降水和前期500 hPa高度场和太平洋海温场资料以及三因子最佳子集回归求最大复相关系数的方法,把前期不同时间步长、不同时段的高度场和海温场同时作为预报因子与汛期降水求相关.结果发现:前期两个场共同作为预报因子比把其中某场单独作为预报因子的相关要好.并且存在着较好的"隔多季度相关"现象.预报因子具有实际预报意义的最佳时段为上一年的6～9月.影响我国汛期降水的最佳预报因子主要集中于高度场和海温场具有重要天气气候意义的关键区域.汛期降水可预报性在北方和长江以南均较好.     

用北太平洋海温场资料制作月降水量预报

使用东营市1963-1996年逐月降水量资料和1962-1996年北太平洋海温资料，采取滚动式相关分析方法，建立了备选因子集。另外，应用逐步回归、最优子集回归、人工神经元网络、多因子EOF迭代等四种统计方法，分析了东营市月降水量与北太平洋海温场的关系。结果表明：东营市月降水量与北太平洋海温场存在显著相关；采用四种统计方法制作东营市月降水量预报，其预报效果均较好。     

基于支持向量机的浙江汛期旱涝预测方法研究

利用浙江省38个测站的降水量资料,得到了能够反映全省旱涝状况的指标,将其作为预报量,通过对前期大气环流场、海温场的相关分析,提取高相关因子,然后运用逐步回归和支持向量机回归技术分别建立浙江省汛期早涝短期气候预测模型,并进行了对比分析.结果表明:支持向量机回归模型集中了众多预报因子的预报信息.有效地利用了支持向量机方法的非线性映射能力,无论在历史样本拟合的精度上还是模型实际预测的能力上都比逐步回归模型有一定提高,有良好的应用前景.     

典型相关分析在台风路径预报中的应用

本文通过对500hPa上的五个因子场分别与台风中心未来48小时和60小时经纬度的预报量场进行典型相关分析,求出由各因子场组成的典型变量,以此作为预报因子,再结合经实践证明预报效果较好的天气学经验因子,用逐步回归方法建立台风中心未来48小时和60小时的路径预报方程。通过对历史样本的拟合和实际试报,表明该方程的预报能力有明显的提高;典型变量权重系数的地理分布与因子场的天气学意义基本吻合。      

用逐步回归模型预测肇庆市汛期降水

用逐步回归方程对肇庆6县(市)分县汛期降水做预测，选取北半球500hPa高度场和太平洋海温场的若干个主分量作为因子(共1748个)。这些因子包含着气候背景场的主要信息，通过对预报量和预报因子群的相关筛选，选取相关系数最大的因子建立逐步回归模型。结果表明：所建立的预报方程的复相关系数高，对肇庆汛期降水预报效果好。     

影响广西热带气旋年频数的神经网络预测模型

利用人工神经网络方法，结合均生函数和逐步回归分析方法对影响广西的热带气旋年频数序列进行神经网络的预测模型研究，该模型既考虑了预报量自身显著周期变化，也考虑了海温场，高度场等因子对预报量的影响，给预报检验，考虑多种影响因子的预测模型比只考虑单一影响因素的预测模型效果好。     

要重视指示性云的观测及编码

以一些易被忽略、简化的指示性云状及编码为依据，论述云天演变，对于观测、记录及编码具有重要意义。     

要重视指示性云的观测及编码

以一些易被忽略、简化的指示性云状及编码为依据,论述云天演变,对于观测、记录及编码具有重要意义。     

对百色工业立市气象信息服务的探讨

就百色工业立市的情况作简要概叙,并在工业立市进程中,除了决策和公益气象服务以外,气象信息服务的市场前景、营销人员队伍、服务中应注意的事项及气象信息服务的可能服务对象和内容作了较为详细的探讨。     

综合布线系统在气象核心网络升级中的应用

综合布线系统采用标准化的语音、数据、图像、监控设备,各线综合配置在一套标准的布线系统上,统一布线设计、安装施工和集中管理维护。综合布线系统在广东省气象局核心网络升级综合布线实际应用效果明显。     

综合布线系统在气象核心网络升级中的应用

综合布线系统采用标准化的语音、数据、图像、监控设备，各线综合配置在一套标准的布线系统上，统一布线设计、安装施工和集中管理维护。综合布线系统在广东省气象局核心网络升级综合布线实际应用效果明显。     

The Impact Of Air-Flow Separation On The Drag Of The Sea Surface

An approach that allows assessment ofthe impact of air-flow separation (AFS) fromwave breaking fronts on the sea-surface drag is presented. Wave breaking fronts are modelled by the discontinuities of the sea-surface slope. It is assumedthat the dynamics of the AFS from wave breaking crests is similar to thatfrom the backward facing step. The form drag supported by an individualbreaker is described by the action of the pressure drop distributed alongthe forward face of the breaking front. The total stress due to the AFS isobtained as a sum of contributions from breaking fronts of different scales.Outside the breaking fronts the drag of the sea surface is supported by theviscous surface stress and the wave-induced stress. To calculate the stressdue to the AFS and the wave-induced stress a physical model of the wind-wavespectrum is used. Together with the model of the air flow described in termsof surface stresses it forms a self-consistent dynamical system for the seasurface-atmosphere where the air flow and wind waves are strongly coupled.Model calculations of the drag coefficient agree with measurements. It is shownthat the dimensionless Charnock parameter (roughness length normalized onthe square of the friction velocity and the acceleration of gravity)increases with the increase of the wind speed in agreement with fieldmeasurements. The stress due to the AFS normalized on the square of thefriction velocity is proportional to the cube of wind speed. At low windsthe viscous surface stress dominates the drag. The role of the form drag,which is the sum of the stress due to the AFS and the wave-induced stress, isnegligible. At moderate and high winds the form drag dominates. At windspeeds higher than 10 m s^-1 the stress supported by the AFS becomescomparable to the wave-induced stress and supports up to 50% of the totalstress.     

黑潮OLR距平指数与华南西部主汛期降水的关系

OLR距平场与华南西部主汛期降水的相关分析场显示,在黑潮区域有强烈的高相关信号反映。黑潮区OLR距平指数与华南主汛期降水的遥相关分析显示,前期黑潮区OLR距平指数的异常,可以成为预测主汛期降水有一定指示意义的前兆信号。并在此基础上建立主成分降维分析方法,对1989~2000年主汛期降水作预测及回代检验,检验结果准确率达75%,说明用黑潮区OLR距平指数作为预报因子可以取得良好的预报成绩。     

The Role Of Halocarbons In The Climate Change Of The Troposphere And Stratosphere

Releases of halocarbons into the atmosphere over the last 50 years are among the factors that have contributed to changes in the Earth’s climate since pre-industrial times. Their individual and collective potential to contribute directly to surface climate change is usually gauged through calculation of their radiative efficiency, radiative forcing, and/or Global Warming Potential (GWP). For those halocarbons that contain chlorine and bromine, indirect effects on temperature via ozone layer depletion represent another way in which these gases affect climate. Further, halocarbons can also affect the temperature in the stratosphere. In this paper, we use a narrow-band radiative transfer model together with a range of climate models to examine the role of these gases on atmospheric temperatures in the stratosphere and troposphere. We evaluate in detail the halocarbon contributions to temperature changes at the tropical tropopause, and find that they have contributed a significant warming of ~0.4 K over the last 50 years, dominating the effect of the other well-mixed greenhouse gases at these levels. The fact that observed tropical temperatures have not warmed strongly suggests that other mechanisms may be countering this effect. In a climate model this warming of the tropopause layer is found to lead to a 6% smaller climate sensitivity for halocarbons on a globally averaged basis, compared to that for carbon dioxide changes. Using recent observations together with scenarios we also assess their past and predicted future direct and indirect roles on the evolution of surface temperature. We find that the indirect effect of stratospheric ozone depletion could have offset up to approximately half of the predicted past increases in surface temperature that would otherwise have occurred as a result of the direct effect of halocarbons. However, as ozone will likely recover in the next few decades, a slightly faster rate of warming should be expected from the net effect of halocarbons, and we find that together halocarbons could bring forward next century’s expected warming by ~20 years if future emissions projections are realized. In both the troposphere and stratosphere CFC-12 contributes most to the past temperature changes and the emissions projection considered suggest that HFC-134a could contribute most of the warming over the coming century.     

On The Influence Of The Eulerian Velocity PDF Closure On The Eddy Diffusion Coefficient

The flux-gradient model, often used to describe turbulent dispersion, implicitly defines an eddy diffusion coefficient K that is known to be related to the Eulerian probability density function (pdf) of the turbulent velocity field. In the strict limit of applicability of Fick's law, the relationship between K and the pdf is used to investigate the influence of non-Gaussianity on dispersion in homogeneous turbulence. A bi-Gaussian pdf is used as a closure model that allows for separate studies of skewness and kurtosis variations. The choice of model parameters can have a significant influence on K, especially when the pdf is bimodal. Both arbitrariness of the closure and bimodality are then reduced using the maximum entropy criterion for the selection of the free parameter of the closure scheme, together with the assumption that the model is valid only for those values of the parameters for which a unimodal pdf is possible. The variations of K are found to be sensitive to both skewness and kurtosis showing a more complex behaviour than that found in literature.     

对夜间云观测的体会

介绍夜间进行云观测的工作程序,对云的特征进行分析,提出了观测云的注意事项。