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Scaling behaviors of precipitation over China 总被引：1，自引：0，他引：1
Scaling behaviors in the precipitation time series derived from 1951 to 2009 over China are investigated by detrended fluctuation analysis (DFA) method. The results show that there exists long-term memory for the precipitation time series in some stations, where the values of the scaling exponent α are less than 0.62, implying weak persistence characteristics. The values of scaling exponent in other stations indicate random behaviors. In addition, the scaling exponent α in precipitation records varies from station to station over China. A numerical test is made to verify the significance in DFA exponents by shuffling the data records many times. We think it is significant when the values of scaling exponent before shuffled precipitation records are larger than the interval threshold for 95 % confidence level after shuffling precipitation records many times. By comparison, the daily precipitation records exhibit weak positively long-range correlation in a power law fashion mainly at the stations taking on zonal distributions in south China, upper and middle reaches of the Yellow River, northern part of northeast China. This may be related to the subtropical high. Furthermore, the values of scaling exponent which cannot pass the significance test do not show a clear distribution pattern. It seems that the stations are mainly distributed in coastal areas, southwest China, and southern part of north China. In fact, many complicated factors may affect the scaling behaviors of precipitation such as the system of the east and south Asian monsoon, the interaction between sea and land, and the big landform of the Tibetan Plateau. These results may provide a better prerequisite to long-term predictor of precipitation time series for different regions over China. 相似文献
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Spatio-Temporal Correlation Analysis of Global Temperature Based on the Correlation Matrix Theory 总被引：1，自引：0，他引：1 
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下载免费PDF全文 TBased on the NCEP/NCAR reanalysis daily mean temperature data from 1948 to 2005 and random time series of the same size, temperature correlation matrixes (TCMs) and random correlation matrixes (RCMs) are constructed and compared. The results show that there are meaningful true correlations as well as correlation "noises" in the TCMs. The true correlations contain short range correlations (SRCs) among temperature series of neighboring grid points as well as long range correlations (LRCs) among temperature series of different regions, such as the El Ni o area and the warm pool areas of the Pacific, the Indian Ocean, the Atlantic, etc. At different time scales, these two kinds of correlations show different features: at 1-10-day scale, SRCs are more important than LRCs; while at 15-day-or-more scale, the importance of SRCs and LRCs decreases and increases respectively, compared with the case of 1-10-day scale. It is found from the analyses of eigenvalues and eigenvectors of TCMs and corresponding RCMs that most correlation information is contained in several eigenvectors of TCMs with relatively larger eigenvalues, and the projections of global temperature series onto these eigenvectors are able to reflect the overall characteristics of global temperature changes to some extent. Besides, the correlation coefficients (CCs) of grid point temperature series show significant temporal and spatial variations. The average CCs over 1950-1956, 1972 1977, and 1996 2000 axe significantly higher than average while that over the periods 1978-1982 and 1991 1996 are opposite, suggesting a distinctive oscillation of quasi-10-20 yr. Spatially, the CCs at 1- and 15-day scales both show band-like zonal distributions; the zonally averaged CCs at 1-day scale display a better latitudinal symmetry, while they are relatively worse at 15-day scale because of sea-land contrast of the Northern and Southern Hemisphere. However, the meridionally averaged CCs at 15-day scale display a longitudinal quasi-symmetry. 相似文献
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Different multi-fractal behaviors of diurnal temperature range over the north and the south of China
Multi-fractal behaviors of diurnal temperature range (DTR for short) from 100 stations over China during 1956–2010 are analyzed by means of multi-fractal detrended fluctuation analysis. By making a Monte-Carlo simulation, we obtain two criterions which can be used to decide whether a DTR series is significantly multi-fractal or not. With these criterions, different multi-fractal behaviors are found over the north and the south of China, and Yangtze River is roughly the dividing line. Over the north region, nearly all the considered DTR series do not show multi-fractal behaviors, while the results are completely the opposite over the south. The findings are confirmed by the scaling behaviors of the corresponding DTR magnitude series and indicate that more scale-dependent structure differences may be hidden in DTR series over the north and the south of China. Therefore, an extensive analysis of the multi-fractal behaviors are essential for a better understanding of the complex structures of the climate changes. 相似文献
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1951～2002年中国平均最高、最低气温及日较差变化 总被引：74，自引：8，他引：66
利用1951～2002年全国733个台站的月平均最高、最低气温资料,对我国年、季平均最高、最低气温变化趋势的空间分布状况和时间变化特征进行了分析.结果表明:近52年来,我国平均最高气温的变化特征呈现北方增暖明显、南方变化不明显或呈弱降温趋势;年平均最低气温全国各地基本一致,呈明显的变暖趋势;无论是年还是季,平均最低气温的增暖幅度明显大于平均最高气温的增幅;我国年平均日较差多呈下降趋势,并在我国北方地区尤为明显,各季平均日较差亦均呈下降趋势,并以冬季的下降幅度为最大;年平均最高气温和最低气温的变化在年代际变化上基本呈现较为一致的步伐,即52年来主要的变暖均是从20世纪80年代中期开始,均在90年代后期达到了近52年来的历史新高,近年来又略有回落. 相似文献
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Comparison of Daily Extreme Temperatures over Eastern China and South Korea between 1996–2005 总被引：1，自引：1，他引：0
This paper examined the decadal mean, seasonal cycle, and interannual variations of mean and extreme temperatures using daily temperature and relative humidity data from 589 stations over eastern China and South Korea between 1996–2005. The results show that the decadal mean Tm (mean daily mean temperature) and the TNn (minimum daily minimum temperature) increase from north to south; the opposite spatial gradient is found in the DTR (diurnal temperature range); the value of the DTR over South Korea is in- b... 相似文献
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中国近50a气候变化复杂性分析 总被引：1，自引：4，他引：1
分析了我国气温和降水量变化的兰帕尔－齐夫复杂度空间分布特征，结果表明，平均而言，我国平均气温和降水量变化的复杂度约为10－11，小于随机序列的复杂度13，年平衡气温变化序列的复杂度最小，秋季平均气温变化序列的复杂度最大，季节和年平均气温序列的复杂度小于月平均气温变化序列的复杂度，月总降水量变化序列的复杂度为西部，北部大于南部和东部，我国东南沿海地区气候要素变化的复杂度最大。 相似文献
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Yonghong Yao Weidong Guo Yaoming Song 《Asia-Pacific Journal of Atmospheric Sciences》2010,46(4):475-481
Using data archived in the Coordinated Enhanced Observing Period (CEOP) project, comparisons between field observations undertaken at Tongyu CEOP reference site in China and model output from year 2003 to 2004 have been implemented, and in particular, the time series and diurnal cycles of precipitation, near-surface temperature, air temperature, and latent and sensible heat fluxes are presented. The results show that the ability of the model simulations on the temperatures, such as air temperature and the surface temperature, is satisfactory compared with the simulations on the land surface heat fluxes and the precipitation at Tongyu site. In addition, the multi-model ensemble exhibits better results over all items in comparison with the observations. The differences of the precipitation at the interannual and the seasonal time scales between the model results and observations indicate that some of the models are able to reproduce the larger amount of precipitation in 2003 than that in 2004, which is consistent with the trend of the observations at Tongyu site even though the mean square errors of models output calculated from daily precipitation during year 2003 and 2004 are even greater than the daily amount of the precipitation. The poor skill in the quantitative simulation of the precipitation indicates that the deficiency of the models in simulating the surface heat fluxes may be closely related to the biases of the precipitation simulations. In terms of the seasonal time series of the precipitation, there is an increase during summer, accompanied by the same increased trend of the latent heat flux and the decreased trend of the sensible heat flux from the insitu observations. 相似文献
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基于历史文献重建的近2000年中国温度变化比较研究 总被引：2，自引：0，他引：2
文中对不同学者利用不同来源中国历史文献资料重建的温度变化代用序列进行了比对,分析了同一地区不同序列之间及不同地区间序列的异同,以及造成这些异同的主要原因。结果表明:(1)不同学者重建的同一地区温度(或冷暖)变化序列具有较高的相似性;不同学者所估计的30 a平均温度相对变幅完全一致(即在99.9%置信水平下,二者通过无显著性差别的检验)的时段平均占所有时段的73.4%,还有8.6%的时段虽在幅度大小上有差异但冷暖定性一致,二者共计占82%。(2)不同地区间的温度变化序列也具有较高的相关性,且重建区域相距越近其相关系数也越高,序列的相似程度也越大;而不同学者所选择的重建方法与代用指标不同并不影响不同地区之间序列的相似程度,说明不同地区序列的不一致应是由于地区的气候变化差异造成的。(3)虽然不同学者所估计的中国过去千年以上的温度变化趋势及波动幅度等存在一定差异,但各家所揭示的中国东部过去2000年主要冷暖阶段的出现时间则基本一致。这些结果进一步说明:以前学术界对各家序列差异的认识可能并没有或很少考虑地区间气候变化的差异,因而夸大了不同学者因重建方法与原始证据不同而造成的重建结果差异,这是不客观的。 相似文献
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By using IAP 9L AGCM, two sets of long-term climatological integration have been per-formed with the two different interpolation procedures for generating the daily surface boundary conditions. One interpolation procedure is the so-called “traditional” scheme, for which the daily surface boundary conditions are obtained by linearly interpolating between the observed monthly mean values, however the observed monthly means cannot be preserved after interpolation. The other one is the “new” scheme, for which the daily surface boundary conditions are obtained by linearly interpolating between the "artificial" monthly mean values which are based on, but are dif-ferent from the observed ones, after interpolating with this new scheme, not only the observed monthly mean values are preserved, the time series of the new generated daily values is also more consistent with the observation. Comparison of the model results shows that the differences of the globally or zonally averaged fields between these two integrations are quite small, and this is due to the compensating effect between the different regions. However, the differences of the two patterns (the global or regional geographical distributions), are quite significant, for example, the magni-tude of the difference in the JJA mean rainfall between these two integrations can exceed 2 mm/day over Asian monsoon regions, and the difference in DJF mean surface air temperature can also exceed 2oC over this region. The fact that the model climatology depends quite strongly on the method of prescribing the daily surface boundary conditions suggests that in order to validate the climate model or to predict the short-term climate anomalies, either the " new* interpolation scheme or the high frequency surface boundary conditions (e.g., daily or weekly data instead of the monthly data) should be introduced. Meanwhile, as for the coupled model, the daily coupling scheme between the different component cli?mate models (e.g., atmospheric and oceanic general circulation models) is preferred in order to partly eliminate the “climate drift” problem which may appear during the course of direct coupling. 相似文献
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Climatological observing window (COW) is defined as a time frame over which continuous or extreme air temperature measurements are collected. A 24-h time interval, ending at 00UTC or shifted to end at 06UTC, has been associated with difficulties in characterizing daily temperature extrema. A fixed 24-h COW used to obtain the temperature minima leads to potential misidentification due to fragmentation of “nighttime” into two subsequent nighttime periods due to the time discretization interval. The correct identification of air temperature extrema is achievable using a COW that identifies daily minimum over a single nighttime period and maximum over a single daytime period, as determined by sunrise and sunset. Due to a common absence of hourly air temperature observations, the accuracy of the mean temperature estimation is dependent on the accuracy of determination of diurnal air temperature extrema. Qualitative and quantitative criteria were used to examine the impact of the COW on detecting daily air temperature extrema. The timing of the 24-h observing window occasionally affects the determination of daily extrema through a mischaracterization of the diurnal minima and by extension can lead to errors in determining daily mean temperature. Hourly air temperature data for the time period from year 1987 to 2014, obtained from Toronto Buttonville Municipal Airport weather station, were used in analysis of COW impacts on detection of daily temperature extrema and calculation of annual temperature averages based on such extrema. 相似文献
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中国北方干旱区地表湿润状况的趋势分析 总被引：85，自引：3，他引：85
利用 1 95 1～ 1 997年中国 1 6 0站月降水和平均气温资料 ,通过计算的地表湿润指数 Hi =PPe(P为观测的月降水总量 ,Pe为月最大潜在蒸发 ) ,对比分析了中国华北、西北两个典型干旱区区域平均地表湿润指数的年代年际变化特征及季节性差异 ,并讨论了它与降水和气温的联系。最后 ,给出了地表湿润指数年及各季节变化趋势的地理分布。研究表明 :西北西部和华北地区的年际及年代际变化趋势基本相反 ,前者地表为变湿趋势 ,后者为变干趋势。华北地区的干化趋势主要发生在夏秋季节 ,而西北除东部的秋季和西部的夏季外 ,其它季节均存在变湿趋势 相似文献
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Lei Jiang Naiming Yuan Zuntao Fu Dongxiao Wang Xia Zhao Xiuhua Zhu 《Theoretical and Applied Climatology》2012,109(1-2):261-270
Daily temperature records including daily minimum, maximum, and average temperature from 190 meteorological stations over China during 1951–2000 are analyzed from two perspectives: (a) long-term persistence in direction of time varies, and (b) standard deviation in direction of amplitude varies. By employing the detrended fluctuation analysis (DFA), we find all the temperature records are long-term correlated, while the exponent α obtained from DFA varies from different districts of China due to different climate conditions, such as the southwest monsoon, subtropical high, northeast cold vortex, and the Tibetan plateau, etc. After we take the standard deviation into account, a new index χ?=?α?×?σ, which has been proposed recently, can be obtained. By further rescaling it as $ \chi = \overline \chi - {{1} \left/ {5} \right.} \times {\sigma_{{\overline \chi }}} $ , we find an obvious change of χ for these three kinds of time series, from which the whole China can be divided into two groups, which are comparatively consistent with dry/wet distributions in the south–north areas over China. 相似文献
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中国冬半年最低气温概率分布特征 总被引：4，自引：0，他引：4
魏凤英 《气候变化研究进展》2008,4(1):8-11
根据1955-2005年中国160个站冬半年 (当年11月至翌年4月)平均最低气温资料,使用统计检验的方法,分析了近50 a中国冬半年最低气温的突变事实,在此基础上给出了气候变暖前后最低气温的概率分布,比较了变暖前后时段全国最低气温空间分布的差异。结果表明：1) 20世纪80年代末中国冬半年最低气温发生了显著突变,进入异常增暖时期,其增温程度比平均气温明显;2) 增暖后中国最低气温的概率分布发生了明显的变化,最低气温偏冷的概率显著减小,偏暖的概率明显增大;3)气候变暖后除西南地区最低气温上升幅度不显著外,其余地区均呈现显著增温趋势。 相似文献
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中国冬半年最低气温概率分布特征 总被引：3，自引：0，他引：3
魏凤英 《气候变化研究进展》2008,4(01):8-11
根据1955-2005年中国160个站冬半年 (当年11月至翌年4月)平均最低气温资料,使用统计检验的方法,分析了近50 a中国冬半年最低气温的突变事实,在此基础上给出了气候变暖前后最低气温的概率分布,比较了变暖前后时段全国最低气温空间分布的差异。结果表明：1) 20世纪80年代末中国冬半年最低气温发生了显著突变,进入异常增暖时期,其增温程度比平均气温明显;2) 增暖后中国最低气温的概率分布发生了明显的变化,最低气温偏冷的概率显著减小,偏暖的概率明显增大;3)气候变暖后除西南地区最低气温上升幅度不显著外,其余地区均呈现显著增温趋势。 相似文献
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Kwang-Yul Kim Ji-Won Kim Maeng-Ki Kim Chun-Ho Cho 《Asia-Pacific Journal of Atmospheric Sciences》2013,49(5):675-685
Daily winter temperatures in Korea have been analyzed via CSEOF analysis. Then, each PC time series was detrended and was fitted to an AR (autoregressive) model. Based on the identified AR model, an artificial time series of arbitrary length can be generated by using an arbitrary white-noise time series. In this way, one hundred new sets of PC time series were generated over the period of 1973–2058. Then, the trend for each PC time series was added back to the artificial PC time series extending the trend until 2058. Ultimately, artificial daily winter temperatures in Korea have been constructed by using the artificial PC time series and the original loading vectors derived from the observational data. The 100 new data sets have been investigated in order to understand the winter temperature variability 50 years into the future. Regression analysis in CSEOF space shows that temperature increase in Korea is associated with increased 850-hPa air temperature over most of the Asian domain (97°-153°E × 22°-73°N) and increased 850-hPa geopotential height in the southern part of the domain. As a result, southerly and southeasterly wind anomalies develop carrying positive temperature anomalies northward and northwestward. Both the 200-hPa air temperature and geopotential height changes indicate that there will be fairly significant northward shift of the jet stream in future. The standard deviation of the 200-hPa potential vorticity increases implying that shortwave trough and henceforth baroclinic instability will increase in future. Finally, GEV (Generalized Extreme Value) distribution and GPD (Generalized Pareto distribution) distribution have been compared between the observational records and the future records of the same length. The extreme value distributions based on the synthetic datasets show that warm extreme events will be more extreme in future and cold extreme events, on the other hand, will be less extreme. This study provides an estimate of future temperatures based on the observational data and serves as an independent baseline solution for comparisons with numerical model solutions. 相似文献
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Using the NCEP-2 reanalysis data in 1979–2015, we analyze variations in the coupled stratosphere–troposphere system and attribute them to the polar vortex oscillation (PVO) and the 11-yr sunspot cycle (SC). Subsequently, influences of PVO and SC on the near-ground temperature and extreme temperatures are diagnosed based on observations at 2419 surface stations in China over the same period. Empirical Orthogonal Function (EOF) analysis of geopotential height (GH) anomalies indicates that the first and second EOF modes together can explain nearly 50% of the total variance and they have different driving sources, active periods, and regions. The first EOF mode mainly represents variation characteristics of the polar vortex, and its active periods appear in late winter. It is found that a weakened polar vortex (larger amplitude in the positive time series of the first mode) corresponds to lower daily mean, minimum, and maximum temperatures and more frequent cold nights and days. This cooling effect mainly occur in northeastern China. The second EOF mode is closely related to the SC, and its major active periods are late autumn and early winter. The results reveal that strong solar activity (larger amplitude in the positive time series of the second mode) leads to cooling effects in northern China through accelerating seasonal transformation of the stratospheric circulation and enhancing intensity of the subtropical westerly jet in the upper troposphere and lower stratosphere. The near-ground temperature is lower than usual, especially for daily mean and minimum temperatures. The number of warm nights and days is significantly reduced, and cold nights and days become more frequent. Therefore, the first and second EOF mode time series of GH anomalies can be used as indices of PVO and solar activity, respectively; and can provide indications of winter cooling processes in China. 相似文献
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利用1951~2000年NCEP/ NCAR 600 hPa逐日再分析资料, 计算候时间尺度能够代表青藏高原地区季风特征的高度场指数序列, 研究青藏高原高度场指数的基本特征及其年代际变化趋势。结果表明:青藏高原地区600 hPa夏季为低压, 冬季为高压, 夏季低压形成的时间呈提早的趋势, 夏季低压强度也呈增强趋势; 青藏高原高度场指数年变化与高原雨日的年变化基本相似。夏季青藏高原高度场指数与同期我国160站的降水和气温相关表明:与降水相关分布从华北到华南呈“-+-”东西向带状分布; 冬季高原高压强度指数与同期气温均为正相关, 青藏高原东侧边缘区和华南地区正相关最为显著。 相似文献