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1.
从物理量因子场与云南盛夏（７－８月）大雨作为预报量之间的相关系数计算入手，通过相关场分析来提取因子信息，经过不同组合试验，选出新的预报因子，检验表明，新的组合因子与预报量之间的相关性有明显提高。由此而建立的预报方程有较好的历史拟合率和较稳定的实际预报能力。 相似文献
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因子的可预报性和预报模型适用性研究初探 总被引：3，自引：0，他引：3
本文从因子场与预报量场之间的整体相关性着手，通过典型相关分析来提取因子信息，用求得的典型变量作为新预报因子，经试用表明，新因子的可预报性比原因子有明显提高。 在预报模型的选择上，本文提出了依据预报模型对历史样本实际预测精度的优劣来衡量预报模型的预测能力，从而选用对历史样本预测精度较高的预报模型作未来预报。 相似文献
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利用计算机技术,将预报因子选取、方程建立和样本拟合融为一体,建立了预报因子选取及方程建立人机交互平台。该平台包括文件信息,因子初选和回归分析三个模块:(1)文件信息模块主要是读取预报对象文件和预报因子文件,显示并检查文件头信息样本长度的一致性;(2)因子初选模块主要是计算各气象要素或物理量场中每个格点因子与预报量之间的相关系数,构成各相关场,分析这些相关场及其关键区域,从中筛选出组合因子;(3)回归分析模块是对选入的组合因子与预报对象进行逐步回归计算,建立预报方程,并根据回归方程参数和样本拟合率,通过改变因子引入和剔除标准来调整回归结果。 相似文献
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本文从对历史样本的实际预测效果探讨了因子的可预报性,并从因子场与预报量场之间的整体相关性着手,通过典型相关分析来提取因子信息,用求得的典型变量作为新的预报因子。经试用表明:新因子的可预报性比原因子有明显加强。 相似文献
5.
利用典型相关分析(CCA)方法建立统计气候预测模型，对我国冬季气温进行了预测试验，采用历史资料独立样本检验的方法，对预报技巧给出合理的评定。结果表明，使用CCA方法对我国冬季气温进行短期气候预测，有一定的预报技巧，对于特定地区和特定时期优选的因子场组合，可以取得较为满意的预报效果。大部分地区的季平均预报时效在2个季以内时，最佳预报相关系数在0.5以上。季平均的预报水平明显高于月平均的预报。海温场是所有因子场中最好的预报因子，不仅单独海温场的预报效果较好，而且与其他因子场组合后的预报水平还可以得到进一步提高。 相似文献
6.
逐步引进因子场作相似预报 总被引：12，自引：2，他引：10
首先通过数学模型计算出不同样本之间的气象因子场的相似系数和表征气象因子场与天气现象之间关系的相关特征量 ,然后用相似系数和相关特征量作参数 ,以预报拟合率为判据 ,逐个引进因子场 ,组建出最优相似预报方程 ,最终作出准确率较高的客观要素预报。 相似文献
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利用T106格点场资料,通过因子组合、相关分析等手段,构造与本地降水关系密切、有明确物理意义的、能反映本地天气系统的动力结构和发展机制的结构特征因子,预报因子和预报量均采用非线性0,1化处理。用MOS预报方法,建立安顺6县(市)的降水分级预报方程。系统从资料采集到结果输出均在微机上实现全自动化,预报结果客观、定量。 相似文献
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在一般的事件概率回归估计予报方法中,所有可能预报因子都是线性的。可是,实际经验表明,仅仅考虑预报量与预报因子之间的线性关系往往还不能确切反映客观规律。因此,寻求非线性因子对于提高预报效果是有意义的。利用布尔结构可以给出对非线性的逻辑代数组合因子进行筛选的方法,我们称为逻辑组合因子的格筛选法。受这一思路启发,我们开展了非线性事件概率回归估计的试验,效果比通常的事件概率回归好。 相似文献
11.
Fluctuations in the length of the growing season in Minnesota 总被引：3，自引：0，他引：3
Fluctuations in growing season length and in the dates of the last spring freeze and first fall freeze between 1899 and 1982 were studied for five rural Minnesota stations with long, high quality records. A general increase in growing season length was found, but there was substantial variation in the pattern of fluctuations among the stations. The increase in growing season length is not clearly and uniformly related to changes in the dates of first and last freezes. The interannual variability of growing season duration is on the order of the increase in duration so that the change would not be readily apparent to a casual observer. Our results do not correspond well with certain other studies of growing season length nor with fluctuations in hemispheric mean temperature. We conclude that extreme care must be used in extrapolating results of growing season length studies in space and in relating them to mean temperature fluctuations. 相似文献
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2002年夏季山东干旱成因分析 总被引：11，自引：4，他引：11
分析了山东省 2 0 0 2年夏季降水、气温特点和干旱情况 ,并从大气环流、北太平洋SST、气候背景等方面对少雨干旱气候的影响进行了分析 ,指出冬季大气环流、北太平洋SST对山东夏季旱涝趋势的预测具有重要的指示意义。 相似文献
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Presented are the results of mercury content measurements in the surface air layer in the Sea of Japan in the period from October 27 to November 11, 2010. It is revealed that the mercury content varied from 0.6 to 3.8 ng/m3. It is demonstrated that the mercury concentration distribution has geographical zoning and depends on the movement of air masses and on the closeness of anthropogenic sources. The maximum mercury concentration is detected in the central part of the sea at the southwestern and southern directions of the wind, that is associated with the industrial emissions of East Asia countries. The minimum mercury concentration corresponding to the concentration in the surface air layer of the Arctic, Atlantic Ocean (Northern Hemisphere), and the Sea of Okhotsk and Bering Sea was observed along the coast of Primorye at the northwestern wind direction. 相似文献
14.
V. I. Byshev V. G. Neiman I. V. Serykh A. D. Shcherbinin 《Russian Meteorology and Hydrology》2007,32(3):183-193
On the basis of long series of contemporary instrumental measurements, the dynamics of waters in the western boundary current of the Indian Ocean is studied. For the first time, the background (quasi-stationary) circulation is estimated, and summer and winter monsoon components of the velocity field are detected. It is shown that the features of water dynamics of the Somali Current pattern are caused by the intensification of circulation during the summer phase, when the background and monsoon velocity fields with the same sign of vorticity are superimposed on each other. During the winter phase, on the contrary, superposition of background and monsoon circulations, with the opposite signs, is associated with a weakening of the resultant velocity of the currents. 相似文献
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1998年洞庭湖流域特大暴雨的雨水情分析 总被引：2，自引：1，他引：1
应用１９９８ 年汛期湖南省９７ 个气象站、２００ 多个水文站的雨量、水文资料,分析了同期洞庭湖流域特大暴雨洪涝的雨水情概况和基本特征。 相似文献
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2020年,长江三峡地区年平均气温17.2℃,接近常年;年平均降水量1530.8毫米,偏多29％,为1961年以来第二多,仅次于1998年.6月,7月降水量及年平均暴雨日数均为1961年以来第二多.平均风速较常年偏大;相对湿度略偏高;各月均无酸雨出现,近十余年酸雨强度呈现明显减弱趋势.2020年,三峡地区夏季暴雨洪涝灾... 相似文献
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Summary From a study of five cases of pronounced fronts in the upper troposphere, it is concluded that the waterspout model offers the most satisfactory solution to the problem of connecting frontal boundaries and tropopauses. Composite cross sections of temperature, potential temperature, normal wind component and potential vorticity are presented for the five cases. On the basis of the potential vorticity measurements it is suggested that the most likely explanation for the formation of the high-level front is a folding of the tropopause.
With 11 Figures
Contribution No. 37, Department of Meteorology and Climatology. —The research reported in this article has been supported by the Geophysical Research Directorate, Air Force Cambridge Research Center, under Contract No. AF 19 (604)-1811. 相似文献
Zusammenfassung Auf Grund einer Untersuchung von fünf Fällen ausgesprochener Fronten in der höheren Troposphäre wird der Schluß gezogen, daß die Wasserhosen-Vorstellung am besten den Zusammenhang zwischen Fronten und Tropopausen darstellt. Kombinierte Querschnitte von Temperatur, potentieller Temperatur, normaler Windkomponente und potentieller Vorticity werden für die fünf Fälle vorgelegt. Auf Grund der Bestimmungen der potentiellen Vorticity wird dargelegt, daß die wahrscheinlichste Erklärung für die Entstehung einer Front in der Höhe in der Annahme einer Faltung der Tropopause besteht.
Résumé En se fondant sur cinq cas de fronts très nets de la haute troposphère, les auteurs concluent que le schéma de trombe constitue la meilleure solution pour représenter la liaison entre zones frontales et tropopause. Ils donnent des profils combinés de température, de température potentielle, de composantes normales du vent et de vorticity potentielle pour les cinq cas. Ils montrent à l'aide de mesures de la vorticity potentielle que l'explication la plus probable de la formation d'un front en altitude consiste à admettre un plissement de la tropopause.
With 11 Figures
Contribution No. 37, Department of Meteorology and Climatology. —The research reported in this article has been supported by the Geophysical Research Directorate, Air Force Cambridge Research Center, under Contract No. AF 19 (604)-1811. 相似文献
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Summary ?This paper deals with variations and trends in some components of the water balance: the soil water content; evaporation
loss from the soil (from the surface and underlying layers); transpiration; ground water recharge and runoff. These components
are calculated by means of the Palmer procedure. This analysis is based on data from Osijek, Croatia from this century (1900–1995).
Besides the meteorological input parameters necessary for the water balance calculations, i.e. precipitation, temperature
and relative humidity, the pedological characteristics of this area have also been taken into account. Fluctuations have been
considered by means of the 11-year binomial filtered series and linear trends were tested by means of the Mann-Kendall rank
test. For a closer look on the trends of water balance components, a progressive analysis of the time series was performed,
too. The results show a significant increase in potential evapotranspiration and evapotranspiration and decrease in runoff
and soil water content has occurred during the century.
Received February 22, 1999/Revised August 3, 1999 相似文献
20.
Dr. R. S. Pulwarty R. G. Barry C. M. Hurst K. Sellinger L. F. Mogollon 《Meteorology and Atmospheric Physics》1998,67(1-4):217-237
Summary Rainfall regimes are primarily unimodal in central and eastern Venezuela but bimodal (peaks in May–June and September-October-November with a minimum in July–August) in the northwest. There is a sharp transition across the Andes suggesting a topographic-circulation connection. However, a mid-summer minimum also occurs at other locations in Venezuela and Central America during individual years. This paper addresses the nature and control of the regimes including the role of large-scale circulation features and convection as indicated by outgoing longwave radiation data. Altitudinal characteristics of precipitation in the Andes and their spatial variability are also investigated. The development of the minimum within the rainy season annual cycle is shown to be related to the combined effects of the evolution of sea surface temperatures in the east Pacific warm pool and reinforced in the area of the Andes by enhanced easterlies during July and August.Abbreviations used in text ENSO
El Nino-Southern Oscillation
- EPWP
East Pacific Warm Pool
- ITCZ
Inter-tropical Convergence Zone
- MEI
Multivariate ENSO Index
- MSM
Mid-Summer Minimum
- NCEP
National Centers for Environmental Prediction
- OLR
Outgoing Longwave Radiation
- SOI
Southern Oscillation Index
- SST
Sea Surface Temperature
With 13 Figures 相似文献