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1.
Yanina L. Romero J. Bessembinder N. C. van de Giesen F. H. M. van de Ven 《Climatic change》2011,106(3):393-405
The Royal Netherlands Meteorological Institute (KNMI) has published the KNMI’06 climate scenarios in 2006. These scenarios
give the possible states of the climate in The Netherlands for the next century. Projections of changes in precipitation were
made for a time scale of 1 day. The urban drainage sector is, however, more interested in projections on shorter time scales.
Specifically, time scales of 1 h or less. The aim of this research is to provide projections of precipitation at these shorter
time scales based on the available daily scenarios. This involves an analysis of climate variables and their relations to
precipitation at different time scales. On the basis of this analysis, one can determine a numeric factor to translate daily
projections into shorter time scale projections. 相似文献
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Dieter Wagner 《Climatic change》1996,33(3):385-407
Based on the principles of the probability theory a statistical model has been developed assessing the likelihood of occurrence of extreme temperature events from the knowledge of the statistical characteristics of the daily temperature extremes. It is demonstrated that the probability of such events is more sensitive to changes in the variability of climate than to changes in its average. Further, this sensitivity increases at a nonlinear rate the more extreme the event. The applicability of the model has been verified by comparing the simulated frequencies of a large spectrum of temperature events with the observed numbers derived from a long time series of daily temperature extremes at Potsdam. Accordingly, the relative simulation errors increase significantly as the events become more extreme. A correction is possible, because most of these errors are systematic rather than random. Moreover, in accordance with the climate observations the simulations reveal statistically significant linear trends in the number of extreme events since the end of the last century. Local scenarios of extreme temperature events have been derived for the city of Berlin by considering both hypothetical new climate states and climate changes simulated by a General Circulation Model (GCM). As a consequence of an increase in the atmospheric concentration of greenhouse gases up to the end of the next century according to the IPCC Scenario A the repetition rate of extreme events in summer (e.g., hot days) is expected to rise considerably relative to the current climate. Moreover, in the winter season cold days will become extremely rare. 相似文献
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Long-term climate monitoring and extreme events 总被引：3，自引：0，他引：3
Neville Nicholls 《Climatic change》1995,31(2-4):231-245
Problems with long-term monitoring of various extreme meteorological events (including tropical and extratropical cyclones, extreme winds, temperatures and precipitation, and mesoscale events) are examined. For many types of extreme events, the maintenance of long-term homogeneity of observations is more difficult than is the case for means of variables. In some cases, however, a strategy of using more than a single variable to define an event, along with the careful elimination of biases in the data, can provide quantitative information about trends. Special care needs to be taken with extreme events deduced from meteorological analyses, because changes in analysis and observation systems are certain to have affected extremes. Also, compositing of observations from more than one station, using differences in means (of temperature for instance) to produce a single long-term site, may not remove the biases in the extremes. These problems, along with ambiguities in defining extreme events, and difficulties in combining different analyses from different sites, complicate (and perhaps invalidate) attempts to determine whether extreme weather is becoming more frequent. The best that is likely to be achieved, even with increased emphasis on attaining the high-level of homogeneity necessary in the observations, is to monitor long-term variations in certain important extreme events, in select locations with high-quality data. Regional indices of important extreme events, selected on the basis of their damage potential and capable of adequate monitoring, may be established. If, in the future, we are to answer the question “Are extreme weather events becoming more frequent?”, we must establish and protect high-quality stations capable of monitoring the most important extreme events (perhaps with such regional indices), and ensure that changes affecting the recording of extreme events (e.g., changes in exposure) are meticulously documented. 相似文献
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本文利用常规地面及高空观测资料、加密自动站资料及多普勒雷达资料等,从环境条件及雷达特征等方面对2019年鸡西市一次极端短时强降水天气进行分析,结果表明:强降水发生在宽广且深厚的西风槽稳定维持背景下,降水区中层有冷空气入侵,低层位于槽前暖湿气流中,一致的西南风输送水汽至降水区。850 hPa槽线是本次对流天气的触发系统,上冷下暖及午后地面温度迅速升高造成热力不稳定,另外,低层绝对水汽含量较高是本次短时暴雨发生的重要条件。从雷达产品上看,麻山区的降水是由多单体风暴形成的,其中包含有超级单体风暴,单体依次经过降水区,强对流过程持续3 h,一定的"列车效应"使其出现了短时暴雨天气。 相似文献
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Trends in extreme rainfall events of Bangladesh 总被引：1，自引：0，他引：1
Shamsuddin Shahid 《Theoretical and Applied Climatology》2011,103(3-4):489-499
Previous studies have shown that urbanization in the Pearl River Delta (PRD) region in southern China can have significant effect on the land-sea breeze circulation in the region. In this study, some characteristics of this urban heat island (UHI) effect are further investigated by some idealized numerical experiments. This study focuses on three aspects of the UHI effects. Firstly, the interaction of UHI effects associated with different city clusters in the PRD region. Secondly, the UHI effect and the strength of the background wind field. Thirdly, seasonal variation of the UHI effect. Experiment results suggest that the interaction of the UHI effects due to the closely distributed city clusters in the PRD region is not significant, while the UHI effect in the region may depend on the strength of the background wind. The seasonal-mean UHI effect in the region shows a significant variation associated with the change of seasons. 相似文献
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Summary Trends in extreme temperatures have been investigated for the Belgrade temperature record (1975–2003) to assess how an increase in the mean summer temperatures is related to changes in the extreme maximum and minimum temperatures. The rising mean summer temperatures at Belgrade are associated with a substantial increase in the occurrence of extreme maximum temperatures. Two statistical models for climate change (changing mean with constant standard deviation, and changing mean and standard deviation) indicated that the changing mean was dominant, because the observed trend in standard deviation was small. 相似文献
10.
Daily minimum and maximum air temperatures recorded in Naples (1872–1982) and in surrounding areas have been analysed in order to set up a statistical model for investigating climatic changes of extreme air temperature. We have analysed on various time-scales the mean values of minimum air temperature lower than the 10th percentile (Tmin10) and the mean values of the maximum air temperature greater than the 90th percentile (Tmax90). The results have shown for the city: (i) a significant secular trend both for yearly Tmin10 and Tmax90, mostly due to the process of urbanization, that is also responsible for (ii) the ascertained change in the character of the annual cycle, (iii) a reasonable ability to forecast winter Tmin10 and summer Tmax90 in statistical terms using a markovian model, and (iv) a significant 11-yr cycle with an amplitude of 0.5 °C directly related to solar activity which has never been succesfully determined before. 相似文献
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P. Domonkos 《Theoretical and Applied Climatology》2001,68(1-2):17-32
Summary Statistical characteristics of accumulated extreme low and high daily mean temperatures have been investigated for Hungary.
Temperature extremes over periods of a few weeks were studied using 96-year temperature records. Temperature is defined as
extreme in the lowest or highest five percent of the empirical distribution of anomalies. Recurrence frequencies of extreme
anomalies were computed at 1, 2,…, 75 days after the initial anomalies, and compared with the respective characteristics of
an appropriate 2nd order autoregressive model. In accordance with the high 1-day lagged autocorrelation in Hungarian temperature time series,
model-frequencies are large for low lags, and approach the value for independence (0.05) for periods longer than 10–15 days.
Considerable similarity of recurrence frequency between observed and simulated series is found but with some important exceptions.
After only 1 extreme cold winter-day or an extreme warm summer-day, the probability of the next extreme occurring with the
same sign remains significantly high for longer than 1 month. Empirical frequencies are very sensitive to the calendar date
of the initial extreme value occurrence. Discrepancies between real and model characteristics were tested for statistical
significance by Monte Carlo simulation technique.
Recurrence frequencies for the last 30 years have also been computed, and intersting similarities and differences were found
relative to the earlier part of the 20th century.
To identify possible relationships between droughts and hot spells, extreme high daily temperatures and dry subperiods during
summers were selected. Recurrence frequencies of extreme positive anomalies in dry periods, more than 15–20 days after an
initial occurrence, are surprisingly high during the second half of the summer.
Received February 15, 2000 Revised September 11, 2000 相似文献
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极端气温和极端降水复合事件的气候特征 总被引：1，自引：0，他引：1
基于1961-2014年的中国台站资料,侧重探讨极端气温和极端降水复合事件的气候特征。结果表明,基于客观方法检测出四类极端复合事件：暖湿、暖干、冷湿和冷干。四类事件的频发区分别位于东北地区、华南地区、西藏及华南地区和长江以南及云贵高原一带。全国暖湿、暖干事件频数呈增加趋势,春夏季频发;冷湿事件频数在西藏东北一带呈增加趋势,而在长江流域呈减少趋势,夏秋冬季频发;冷干事件频数呈减少趋势,秋冬季频发。四类极端复合事件经验正交分解的时间序列主模态均表现为年代际信号。进一步分析四类复合事件与能源消费量的联系表明,极端湿事件与能源消费量呈正相关,而极端干事件则相反。 相似文献
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Compared are the parameters of the cyclone activity in some areas of the North Atlantic in the winter (from October to March) and summer (from April to September) seasons for the period from January 1, 1948 to March 31, 2010, as well as the activity for the cyclones with the moderate intensity with the pressure in the center from 1000 to 970 hPa and for extremely intense cyclones (970 hPa and lower). The characteristics of cyclone activity, the density and intensity of cyclones, are determined using a method of the automatic identification of cyclone centers from the data on the sea level pressure. 相似文献
16.
Jean Laflamme 《Atmospheric Research》1995,36(3-4)
It is still a challenge today to get the statistical approach accepted by some transmission line engineers, namely for freezing rain icing loads. They see heavy icing storms as rare events and they still believe that in this case a sound engineering judgment is better than poor statistics. When they are convinced that statistics are good, such as for the flood problem, they do not hesitate to accept the probabilistic approach. Developing extreme values distributions of freezing-rain icing is however a difficult task. Because of the relatively small dimension of major freezing rain storms, freezing-rain icing is not a continuous “variate” at a particular site.One way of improving the statistics is to take simple icing measurements on a fine grid stations network. After only 17 years of measurements with Passive Ice Meters, good fit of extreme values is possible if we use “mesh”extreme values instead of “station” ones. Before pooling extreme values into a “mesh” or “region”distribution, some attention must be given to the homogeneity of the data within a given area. This has been done for four different regions of the province of Québec with very conclusive results. A mesh of about 50 km seems adequate with a temporal resolution of 12 h. Since transmission lines are spatial constructions, this finding can easily satisfy the need of the design engineers in defining icing loads. And, if some caution is given to identify special topographical features, a better knowledge of the spatial variation of icing makes also possible better line routing. 相似文献
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Mediterranean basins can be impacted by severe floods caused by extreme rainfall, and there is a growing awareness about the possible increase in these heavy rainfall events due to climate change. In this study, the climate change impacts on extreme daily precipitation in 102 catchments covering the whole Mediterranean basin are investigated using nonstationary extreme value model applied to annual maximum precipitation in an ensemble of high-resolution regional climate model (RCM) simulations from the Euro-CORDEX experiment. Results indicate contrasted trends, with significant increasing trends in Northern catchments and conversely decreasing trends in Southern catchments. For most cases, the time of signal emergence for these trends is before the year 2000. The same spatial pattern is obtained under the two climate scenarios considered (RCP4.5 and RCP8.5) and in most RCM simulations, suggesting a robust climate change signal. The strongest multi-model agreement concerns the positive trends, which can exceed +?20% by the end of the twenty-first century in some simulations, impacting South France, North Italy, and the Balkans. For these areas, society-relevant strong impacts of such Mediterranean extreme precipitation changes could be expected in particular concerning flood-related damages. 相似文献
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Summary ¶Temporal changes in the occurrence of extreme events in time series of observed precipitation are investigated. The analysis is based on a European gridded data set and a German station-based data set of recent monthly totals (1896/1899–1995/1998). Two approaches are used. First, values above certain defined thresholds are counted for the first and second halves of the observation period. In the second step time series components, such as trends, are removed to obtain a deeper insight into the causes of the observed changes. As an example, this technique is applied to the time series of the German station Eppenrod. It arises that most of the events concern extreme wet months whose frequency has significantly increased in winter. Whereas on the European scale the other seasons also show this increase, especially in autumn, in Germany an insignificant decrease in the summer and autumn seasons is found. Moreover it is demonstrated that the increase of extreme wet months is reflected in a systematic increase in the variance and the Weibull probability density function parameters, respectively.Received July 18, 2002; revised January 24, 2003; accepted February 1, 2003
Published online September 10, 2003 相似文献
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无锡极端气温事件的气候分析 总被引：1，自引：1，他引：0
为了解气候增暖情况下,无锡地区极端最高和最低气温的气候特征,用阈值检测方法对无锡市1959-2007年的日最高气温、日最低气温进行了研究,分析了极端事件的发生规律,得出主要结论:(1)从年代际看,不论是日最高气温或日最低气温,2001-2007年偏高事件最多,偏低事件最少.(2)最低气温从1980s初开始稳定上升.(3)在3、5、7、12月比较容易出现异常的气温.月内异常气温出现次数多少主要与季节更替和天气系统的转换有关.(4)日最低气温不论冬春夏秋,都是明显升高.日最高气温冬、春、秋季呈升高趋势,而夏季震荡加大.即在夏季,日最高气温偏高的事件增多,日最高气温偏低的事件也增多. 相似文献
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C. G. Menéndez M. de Castro J.-P. Boulanger A. D’Onofrio E. Sanchez A. A. Sörensson J. Blazquez A. Elizalde D. Jacob H. Le Treut Z. X. Li M. N. Núñez N. Pessacg S. Pfeiffer M. Rojas A. Rolla P. Samuelsson S. A. Solman C. Teichmann 《Climatic change》2010,98(3-4):379-403
We investigate the performance of one stretched-grid atmospheric global model, five different regional climate models and a statistical downscaling technique in simulating 3 months (January 1971, November 1986, July 1996) characterized by anomalous climate conditions in the southern La Plata Basin. Models were driven by reanalysis (ERA-40). The analysis has emphasized on the simulation of the precipitation over land and has provided a quantification of the biases of and scatter between the different regional simulations. Most but not all dynamical models underpredict precipitation amounts in south eastern South America during the three periods. Results suggest that models have regime dependence, performing better for some conditions than others. The models’ ensemble and the statistical technique succeed in reproducing the overall observed frequency of daily precipitation for all periods. But most models tend to underestimate the frequency of dry days and overestimate the amount of light rainfall days. The number of events with strong or heavy precipitation tends to be under simulated by the models. 相似文献