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1.
基于Lorenz系统提取数值模式可预报分量的初步试验 总被引：1，自引：0，他引：1
针对数值预报模式中存在的非线性混沌特性, 从提取可预报分量的思路出发, 阐述了在数值模式中提取可预报分量的方法, 并利用Lorenz系统进行了相关数值试验。研究发现, Lorenz系统初始误差在相空间中的增长速度是不同的, 某些方向的误差增长速度较慢, 即存在对初值扰动不敏感、相对稳定的可预报分量。根据数值模式切线性误差算子的特征值演化规律, 提取出数值模式的可预报分量, 并将模式变量在其基底上进行投影变换, 建立了可预报分量数值模式。在此基础上, 研究了Lorenz系统的混沌状态、模式参数误差及外部随机噪声对提取可预报分量的影响, 发现基于可预报分量的数值模式, 具有更好的预报技巧。 相似文献
2.
The analysis is given of the present situation and current preparedness of available approaches to the implementation of the Roshydromet concept of the improvement of environmental pollution monitoring system taking into account differences in goals and objectives that different components of this system should achieve at the federal, regional, and local levels. The structure and functional scheme of the National environmental pollution monitoring system is discussed. The approximate allocation of functions is put forward among the monitoring system components of different levels as well as the distribution of responsibilities and powers among stakeholders to ensure the implementation of these functions. The key issues of establishing an integrated monitoring system are discussed. The network-centric approach to the system management organization is proposed. Specific goals, objectives, and strategies can be set for different components of this system which may differ in terms both of algorithms and actual parameters. The development of the main technological components of the integrated environmental monitoring system (monitoring networks and information systems) is considered. 相似文献
3.
将非平衡风分成两部分:(1)非平街风的旋度部分(?)′_R和(2)非平衡风的散度部分(?)′_D。在产生暴雨的次天气尺度系统中,这两种非平衡风具有同样重要的作用。所以在有限区域细网格模式的初值化中,不能只考虑散度风,即使用通常称为“散度初值化”的方案,而且要考虑非平衡风的旋度部分。根据散度方程分析,(?)′_R是维持、调整散度场的重要因子。试验了三种风场初值化方案,结果表明,在风场初值中同时考虑(?)′_R和(?)′_D,可以明显改善模式的降水预报。 相似文献
4.
利用1961—2004年云南124个气象站逐月降水 (P) 和气温 (t) 观测资料, 依据高桥浩一郎的陆面实际蒸散发经验公式 (以下简称高桥公式), 计算了云南地面蒸发 (E) 和可利用降水 (P-E) 等与水资源有关的主要物理量, 从大气可提供的水资源部分, 分析了云南水资源各分量的时空演变特征及其显著周期, 并对云南水资源进行了初步的区划。结果表明:云南大气中水资源各分量区域分布差异显著, 南多北少, 南部梯度大, 北部梯度小; 云南水资源各分量P, E及P-E季节变化明显, 夏季各量最大, 多年平均分别为548 mm, 236 mm, 313 mm, 各占全年的55%, 45%及67%, 冬季各量最小, 所占全年的比例也最小, 分别为5%, 7%, 2%;云南P, E及P-E存在明显的月际、年际及年代际变化特征, 各分量最大值出现在7月, 最小值出现在1月或12月, 通过功率谱周期分析发现, 年降水量和可利用降水量存在显著的2.6年周期, 年蒸发量存在显著的2.9年周期; 云南省初步可划分为水资源丰富区、缺少区及一般区3个区, 它们的区域平均P-E, E及P都存在明显差异。 相似文献
5.
A regression-based downscaling technique was applied to monthly mean surface wind observations from stations throughout western Canada as well as from buoys in the Northeast Pacific Ocean over the period 1979–2006. A predictor set was developed from principal component analysis of the three wind components at 500?hPa and mean sea-level pressure taken from the NCEP Reanalysis II. Building on the results of a companion paper, Curry et al. (Clim Dyn 2011, doi:10.1007/s00382-011-1173-3), the downscaling was applied to both wind speed and wind components, in an effort to evaluate the utility of each type of predictand. Cross-validated prediction skill varied strongly with season, with autumn and summer displaying the highest and lowest skill, respectively. In most cases wind components were predicted with better skill than wind speeds. The predictive ability of wind components was found to be strongly related to their orientation. Wind components with the best predictions were often oriented along topographically significant features such as constricted valleys, mountain ranges or ocean channels. This influence of directionality on predictive ability is most prominent during autumn and winter at inland sites with complex topography. Stations in regions with relatively flat terrain (where topographic steering is minimal) exhibit inter-station consistencies including region-wide seasonal shifts in the direction of the best predicted wind component. The conclusion that wind components can be skillfully predicted only over a limited range of directions at most stations limits the scope of statistically downscaled wind speed predictions. It seems likely that such limitations apply to other regions of complex terrain as well. 相似文献
6.
通过采集武汉市土壤风沙尘、建筑水泥尘、城市扬尘、餐饮源、生物质燃烧源、工业煤烟尘和电厂煤烟尘等7类源样品,并分析其碳组分、水溶性离子组分和无机元素组分,建立PM10和PM2.5源成分谱.研究表明,地壳元素Si、Ca、Al以及Fe等是土壤风沙尘的主要特征组分,其中Si是含量最高的成分,也是土壤风沙尘的标识组分.无组织建筑水泥尘中Si和Ca元素含量较高,将Ca元素作为无组织建筑水泥尘区别其他源类的重要元素,而有组织建筑水泥尘中OC、SO42-含量比无组织建筑水泥尘高.城市扬尘中Ca的含量相对较高,表明城市扬尘受到建筑水泥尘影响较多.生物质燃烧源成分谱中OC的含量远高于成分谱中其他组分,另外Cl-和K的平均含量也较高,K一般为生物质源的特征元素. 相似文献
7.
The spatial organization of decadal and bidecadal components (fluctuations) of annual rainfall is identified in this research for two regions: (1) southern South America, and (2) southern North America (conterminous USA, southeastern Canada and northern and central Mexico). Findings indicate that these decadal and bidecadal components have highly coherent wave-like spatial organization. Two types of organization of decadal and bidecadal components of annual rainfall were identified: a train of propagating fluctuations and quasi-standing fluctuations. For decadal components, such patterns alternate in time. A widespread change in the spatial organization of decadal component of annual rainfall took place simultaneously in both continents in 1932. The bidecadal component is organized as standing fluctuations in southern North America and as travelling fluctuations in southern South America, The spatial pattern of decadal fluctuations of annual rainfall has 12- and 13-year cycles, and the spatial pattern of bidecadal fluctuations has predominantly 21- and 22-year cycles. 相似文献
8.
A. Zastawny 《Meteorology and Atmospheric Physics》2006,92(1-2):153-159
Summary Using the HITRAN database from 2003, the absorption of solar and thermal radiation by the atmosphere is calculated. The results
are presented in the form of spectral densities of absorption yield of the atmosphere and its components, and fractions of
absorbed energy of the solar radiation and thermal radiation in the atmosphere by each of its components separately and together.
Finally, the obtained results are discussed in the context of the lately published model of Earth’s radiation budget-MAP 85(4),
275–281 (2004). The shares of atmospheric components in the greenhouse effect and in the absorption of solar radiation are
calculated. The percentage contributions of the more important atmospheric components in the greenhouse effect are as follows:
clouds 66, water vapor 25, CO2 6.7, N2O 0.7, CH4 0.7. 相似文献
9.
Data assimilation systems usually assume that the observation errors of wind components, i.e., u(the longitudinal component) and v(the latitudinal component), are uncorrelated. However, since wind components are derived from observations in the form of wind speed and direction(spd and dir), the observation errors of u and v are correlated. In this paper, an explicit expression of the observation errors and correlation for each pair of wind components are derived based on the law of error propagation. The new data assimilation scheme considering the correlated error of wind components is implemented in the Weather Research and Forecasting Data Assimilation(WRFDA) system. Besides, adaptive quality control(QC) is introduced to retain the information of high wind-speed observations. Results from real data experiments assimilating the Advanced Scatterometer(ASCAT) sea surface winds suggest that analyses from the new data assimilation scheme are more reasonable compared to those from the conventional one, and could improve the forecasting of Typhoon Noru. 相似文献
10.
Zh. A. Balonishnikova O. I. Krestovskii V. A. Shutov 《Russian Meteorology and Hydrology》2010,35(12):832-841
Results of detecting water balance components of experimental watersheds from long-term observations at the Valdai Affiliation
of the SHI are presented. Methods of measurements, calculations, and corrections of precipitation amount, measurement of evaporation
from the land, changes in the soil moisture reserves and ground water reserves are considered. All components of the water
balance of watersheds are measured independently which allows estimating quantitatively the residuals and measurement and
calculation errors. A preliminary analysis is performed of seasonal values of the water balance components and their changes
in the period of most intensive observations (1952–1985) which is of a great value for studying the conditions of the river
runoff formation in small watersheds. 相似文献
11.
12.
《Dynamics of Atmospheres and Oceans》2001,33(2):135-156
Symmetry properties of steady solutions of the barotropic quasigeostrophic vorticity equation are explored using mirror reflections with respect to mid-basin longitude and latitude. The analysis is conducted by perturbing the fully inertial solution, the zeroth-order solution or the Fofonoff mode, by introducing forcing and dissipation as a first order correction. In the context of a classical square-basin and single-gyre circulation subject to bottom friction, it is shown numerically and analytically that the full solution can be approximated by the superposition of three components each having definite symmetry properties under longitude and latitude reflections: the north–south symmetric and antisymmetric components of the zeroth-order solution and the east–west antisymmetric component of the first-order correction. The flow patterns of the individual components are discussed. 相似文献
13.
Y. Shao 《Meteorology and Atmospheric Physics》2002,81(3-4):191-205
Summary ?This paper is concerned with the chaotic behavior of a coupled system consisting of two components, one representing the
atmosphere and the other representing the ocean. The system is expressed as a highly truncated spectral model and for each
component, the spectral model is similar to that of Lorenz (1963). Interactions between the two components are permitted,
which lead to the temporal variation of surface temperature and hence that of a critical model parameter (the Rayleigh number).
The emphasis of the paper is placed upon the chaotic behavior arising from the interactions between the two components and
from periodic external forcing. Numerical tests are carried out to show that through interactions, the chaotic behavior of
one component may result in chaos of the other even if the latter is otherwise stationary or periodic. It is shown that chaos
may also occur if the system is forced periodically at certain frequencies. This study indicates that a new mechanism for
chaos exists for coupled systems which are subject not only to internal fluid dynamic nonlinear interactions, but also to
interactions between different components and external forcing.
Received July 24, 2001; revised March 25, 2002 相似文献
14.
M. V. Bolgov E. A. Korobkina M. D. Trubetskova I. A. Filippova 《Russian Meteorology and Hydrology》2018,43(10):639-645
The main components ofthe Caspian Sea water balance and water level are assessed. Stochastic models of time series of the water balance components are proposed ustng morphometric dependences specified by creating and processing digital elevation models for the flooded areas. The sea level forecast is obtained by the method of simulation modeling based on algorithms for the generation of Markovian random sequences with non-Gaussian marginal distributions. 相似文献
15.
Understanding the responses of mean and extreme precipitation to climate change is of great importance.Previous studies have mainly focused on the responses to prescribed sea surface warming or warming due to increases of CO2.This study uses a cloud-resolving model under the idealization of radiative-convective equilibrium to examine the responses of mean and extreme precipitation to a variety of climate forcings,including changes in prescribed sea surface temperature,CO2,solar insolation,surface albedo,stratospheric volcanic aerosols,and several tropospheric aerosols.The different responses of mean precipitation are understood by examining the changes in the surface energy budget.It is found that the cancellation between shortwave scattering and longwave radiation leads to a small dependence of the mean precipitation response on forcings.The responses of extreme precipitation are decomposed into three components(thermodynamic,dynamic,and precipitation efficiency).The thermodynamic components for all climate forcings are similar.The dynamic components and the precipitation-efficiency components,which have large spreads among the cases,are negatively correlated,leading to a small dependence of the extreme precipitation response on the forcings. 相似文献
16.
Statistical time series decomposition into significant components and application to European temperature 总被引：1，自引：0，他引：1
Summary
Time series of observed monthly mean temperatures of European stations and at grid points are decomposed into different kinds
of trends (linear, progressive, degressive), constant or significantly changing annual cycles, episodic and harmonic components,
extreme events and noise. A stepwise regression is used to test whether the components are significant. Special emphasis is
given to extreme events which we distinguish from extreme values. While extreme values may likely occur by chance, it is very
unlikely that extreme events would be in accordance with the features of the time series. On one hand, extreme events alter
the estimates (and test results) of trends and other components. On the other hand, such components have to be known to recognize
extreme events. To deal with this problem, an iterative procedure is introduced that converges fast to robust estimates of
all the components.
Applying this procedure to the last 100 years of European temperatures reveals that the phase of the annual cycle is shifted
backward within the year in western Europe but foreward in eastern Europe. In the latter region, the amplitude of the annual
cycle has also increased significantly. Most of the trend components found in the time series are positive and linear. Nearly
all detected extreme events are cold events which occurred in winter. Their number has significantly grown. Significant harmonic
components with a period of 92.3 months (about 7.7 years) are found mainly in northern and western Europe.
Received August 15, 2000 Revised June 20, 2001 相似文献
17.
The Influence of Large-Scale Circulation on the Summer Hydrological Cycle in the Haihe River Basin of China 
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下载免费PDF全文 OU Tinghai LIU Yanxiang CHEN Deliang David RAYNER ZHANG Qiang GAO Ge XIANG Weiguo 《Acta Meteorologica Sinica》2011,25(4):517-526
In this study, we focus on changes in three important components of the hydrological-cycle in the Haihe River basin (HRB) during 1957-2005: precipitation (Prep), actual evaportranspiration (ETa), and pan evaporation (PE)-a measure of potential evaporation. The changes in these components have been evaluated in relation to changes in the East Asian summer monsoon. Summer Prep for the whole basin has decreased significantly during 1957-2005. Recent weakening of the convergence of the integrated water vapor flux, in combination with a change from cyclonic-like large-scale circulation conditions to anti-cyclonic-like conditions, led to the decrease in the summer Prep in the HRB. ETa is positively correlated with Prep on the interannual timescale. On longer timescales, however, ETa is less dependent on Prep or the large-scale circulation. We found negative trends in ETa when the ERA40 reanalysis data were used, but positive trends in ETa when the NCEP/NCAR reanalysis data were used. PE declined during the period 1957-2001. The declining of PE could be explained by a combination of declining solar radiation and declining surface wind. However, the declining solar radiation may itself be related to the weakening winds, due to weaker dispersion of pollution. If so, the downward trend of PE may be mainly caused by weakening winds. 相似文献
18.
Vertical coherence and phase delay between wind components in strong winds in the lowest 20 m over uniform terrain in New Zealand have been analysed. The vertical decay constants and slopes for the horizontal wind components could be described as linear functions of the ratio of vertical spacing to mean height (δz/z), with relatively little scatter. The decay constants for the lateral were smaller than for the longitudinal components, the slopes larger for the lateral components, as found previously. The coherence of vertical velocity is best described by exponential decay functions multiplied by a parameter which decreases linearly from 1 (for δz/z=0) to 0.5 (for δz/z=1). The decay constants increased linearly with δz/z, as in the case of the horizontal components. There were no significant phase differences for the vertical components. Lateral and vertical decay constants for the longitudinal wind component could be fitted to identical functions of δy/z and δz/z, respectively. 相似文献
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20.
为了研究和揭示宁夏南部地气能量传输过程及特点并进一步评估退耕还林还草的生态效应, 利用Landsat-7 ETM+卫星遥感资料所求取的地表特征参数, 将地表分成水体、裸地、半裸地、草地、林地5类地表覆盖类型, 结合常规气象观测资料, 分别计算得出宁夏南部地表辐射和热量平衡各量的区域分布, 并给出各量的分布图和直方图, 分类别讨论了地表辐射和热量平衡各量分布特征, 使得对宁夏南部区域地表辐射和热量平衡区域分布有一个直观、综合的了解和认识。研究表明, 植被分布对地表辐射和热量平衡各量影响很大。 相似文献