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Spatiotemporal characteristics and water budget of water cycle elements in different seasons in northeast China 下载免费PDF全文
In this paper, we study the spatiotemporal characteristics of precipitable water, precipitation, evaporation, and water–vapor flux divergence in different seasons over northeast China and the water balance of that area. The data used in this paper is provided by the European Center for Medium-Range Weather Forecasts(ECMWF). The results show that the spatial distributions of precipitable water, precipitation, and evaporation feature that the values of elements above in the southeastern area are larger than those in the northwestern area; in summer, much precipitation and evaporation occur in the Changbai Mountain region as a strong moisture convergence region; in spring and autumn, moisture divergence dominates the northeast of China; in winter, the moisture divergence and convergence are weak in this area. From 1979 to 2010, the total precipitation of summer and autumn in northeast China decreased significantly; especially from 1999 to 2010, the summer precipitation always demonstrated negative anomaly. Additionally, other elements in different seasons changed in a truly imperceptible way. In spring, the evaporation exceeded the precipitation in northeast China; in summer, the precipitation was more prominent; in autumn and winter, precipitation played a more dominating role than the evaporation in the northern part of northeast China, while the evaporation exceeded the precipitation in the southern part.The Interim ECMWF Re-Analysis(ERA-Interim) data have properly described the water balance of different seasons in northeast China. Based on ERA-Interim data, the moisture sinks computed through moisture convergence and moisture local variation are quite consistent with those computed through precipitation and evaporation, which proves that ERAInterim data can be used in the research of water balance in northeast China. On a seasonal scale, the moisture convergence has a greater influence than the local moisture variation on a moisture sink, and the latter is variable slightly, generally as a constant. Likewise, in different seasons, the total precipitation has a much greater influence than the evaporation on the moisture sink. 相似文献
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引进拟小波方法数值求解对流扩散方程,研究结果表明,计算带宽W有一个极值,当计算带宽W取该极值时,该方程的拟小波解的精度最高,且好于迎风格式。当边界发生随机不等幅扰动时,对于积分时间较长的情况,拟小波格式的效果要稍逊于迎风格式;当边界发生随机等幅扰动时,若计算带宽W取大于等于20的整数时,方程拟小波解的精度与迎风格式相同;当参数受到随机扰动时,W取10时的拟小波解的均方根误差要小于迎风格式;在初值发生随机扰动且计算带宽W取10时,方程的拟小波解的精度最高,好于迎风格式。 相似文献
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考虑了一种无反馈的作用机理,通过分析定常强迫作用下R?ssler系统的分岔图和Lyapunov指数谱,发现定常强迫能够导致混沌系统产生振幅死亡.这种现象的产生类似于耦合的极限环系统和耦合的R?ssler系统,弱定常强迫作用下的R?ssler系统经由一个周期运动被驱动到系统自身的一个平衡点上.进一步对受迫系统时间序列的研究表明,当定常强迫强度超过一个临界值时,系统的状态不断在小振幅周期运动与静止之间交替出现.
关键词:
振幅死亡
定常强迫
R?ssler系统 相似文献
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选取全球历史气候网日值数据集中4个具有长时间大气温度序列的站点并统计其逐月距平值, 利用二阶去趋势的涨落分析法分析研究站点不同时段的气温序列长程相关性特征, 并计算4站在不同时段的最高气温、最低气温的相对变化趋势. 利用傅里叶滤波法生成具有与各站不同时段气温序列相同的长程相关性强度及数据长度相等的代用序列, 并估算出其源于系统内部自然变率的“增/降温”范围, 经分析可知气温序列内部自然变率导致的趋势变化范围与其长度成反比, 而与序列的长程相关性强弱成正比. 最后对比实际温度序列的相对变化趋势以及在95%和99%的置信概率下自然变率的趋势范围, 除SAGINAW MBS INTL AP站日最高气温序列外, 各站点的日最高气温和最低气温长时间序列普遍表现为明显的外部变化趋势, 近30年各站最高、最低气温序列的变化趋势则未超自然变率的趋势范围, 虽不能排除外部趋势的存在, 但与气候系统内部各因子相互作用的影响相比, 这种外部趋势并不显著. 该方法可判别全球变暖背景下气候因子的变化趋势是否显著地由气候系统外部因子引起, 从而能有针对性地对系统外(内)部影响因子展开进一步的研究. 相似文献
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定义一个动态窗口,以Lorenz模型为预报方程,通过对落入动态窗口中的粒子数和平均预报X分量随积分时间演化规律的分析,从另一个角度初步研究了Lorenz系统的可预报性问题,并讨论了高斯白噪声对系统可预报性的影响.结果表明,落入动态窗口中的粒子数在一定程度上反映了系统的可预报性,处于不同区域的初值集合预报时限各不相同,且不同区域内的初值对于小扰动的敏感程度不一样;对于不同区域内的初值集合,高斯白噪声对系统的可预报时限的影响各不相同.
关键词:
可预报性
Lorenz
动态窗口 相似文献
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A new nickel(II) complex [NiL2](DMF)4 (HL = 2'-[4-N,N'-(dimethylamino- benzylidene)]-3,5-dihydroxybenzoylhydrazide) has been synthesized and its structure was characterized by IR,UV-Vis,1H NMR and elemental analysis. The fluorescence emission mechanism of the complex was discussed by fluorimetric spectra. The single-crystal structure was determined by X-ray diffraction analysis. The crystal belongs to the triclinic system,space group P1 with a = 0.9918(4),b = 1.1297(4),c = 1.1331(4) nm,α = 76.860(7),β = 75.105(6),γ = 89.022(7)°,V = 1.1936(8) nm^3,Z = 1,μ = 0.472 mm^-1,Dc = 1.319 g/cm^3,F(000) = 502 and Rint = 0.0913. In the title compound,the nickel(II) atom is four-coordinated with two nitrogen atoms from amide and two oxygen atoms from keto group. The complex is centrosymmetric with nickel located at the center. 相似文献
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