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通过对１９９６年黔南６月１日与６月２０日两次大范围强降水天气过程的对比分析发现：６月１日强降水由８５０ｈＰａ低涡切变东南移造成，降水强度大，影响时间短，云团结构紧凑；６月２０日强降水由冷锋南移造成的，降水强度小，影响时间长，云团结构前紧后松，６月１日与６月２０日暴雨云团的发展区均是高能区，区别在于６月１日暴雨云团的生成比６月２０日暴雨云团的生成需要更多的不稳定能量。 相似文献
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分析了１９９４年８月１日出现在青州市西南山区的一次局地强降水过程。研究了地形、大尺度天气背景以及中－β尺度系统对局地强降水的作用以及暴雨云团的一些特征，对山区局地大暴雨的预报有一定的参考价值。 相似文献
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对１９９５年６月３０日－７月１日华北高空冷涡的强降水过程作了详细分析，探讨了冷锅演变的物理量场分布特征及其云系变化与降水的对应关系，为日常业务预报提供了一些启示。 相似文献
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通过常规气象资料、卫星云图和Ｔ１０６数值预报产品中的要素场和物理量场资料,分析了青海东部地区１９９９年６月１３日夜间到１４日强降水天气过程,得出了一些预报强降水天气过程的依据。 相似文献
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通过对2002年4月3日20时至4日08时青海省东部农业区强降水天气过程的物理量诊断分析，揭示了高原春季产生强降水天气过程的动力和热力条件，确定了产生这次高原春季强降水的一些物理特征量，加深了对强降水天气发生、发展的认识。 相似文献
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该文以长江三峡地区６个站１９６１－１９９４年１０月－１月的逐日降水量来确定该地区发生区域性强降水的雨日，用同期的历史天气图分析产生区域性强降水的原因，影响系统和环流形势２，归纳出长江三峡地区产生区域性强降水的６类环流型，并进行逐日反查，概括出两类环流型产生区域性强降水的预报指标。 相似文献
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由于强降水而引发的洪涝是辽宁的主要灾害之一，做好强降水预报是做好洪涝预报的基础。中期预报以其较长的时效性，愈来禽引起人们的重视。随着科学技术的发展，在3～6天中期预报时效内准确预报强降水已成为可能。据统计，在综合考虑全省平均及分片平均候累积降水量的前提下，1961-1994年夏季辽宁省共发生强降水过程43次、较强降水过程40次。强降水过程不同于干旱过程，强降水过程一般具有突发性和持续时间短的特点，发生较强降水或强降水过程往往决定于候内一次降水过程的强度和持续时间。 相似文献
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１９９５．７．１７陕北强降水诊断分析段桂兰，梁生俊（陕西省气象台西安·７１００１５）１９９５年７月１７日０８时到１８日０８时，陕北出现一次强对流性强降水过程，陕北六县出现暴雨，其中，府谷、子洲两县大暴雨。１天气形势１７日０８时３００ｈＰａ高空图上，河... 相似文献
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A. K. Guèye Serge Janicot A. Niang S. Sawadogo Benjamin Sultan A. Diongue-Niang S. Thiria 《Climate Dynamics》2012,39(9-10):2251-2272
The aim of this work is to define over the period 1979–2002 the main synoptic weather regimes relevant for understanding the daily variability of rainfall during the summer monsoon season over Senegal. “Interannual” synoptic weather regimes are defined by removing the influence of the mean 1979–2002 seasonal cycle. This is different from Part I where the seasonal evolution of each year was removed, then removing also the contribution of interannual variability. As in Part I, the self-organizing maps approach, a clustering methodology based on non-linear artificial neural network, is combined with a hierarchical ascendant classification to compute these regimes. Nine weather regimes are identified using the mean sea level pressure and 850?hPa wind field as variables. The composite circulation patterns of all these nine weather regimes are very consistent with the associated anomaly patterns of precipitable water, mid-troposphere vertical velocity and rainfall. They are also consistent with the distribution of rainfall extremes. These regimes have been then gathered into different groups. A first group of four regimes is included in an inner circuit and is characterized by a modulation of the semi-permanent trough located along the western coast of West Africa and an opposite modulation on the east. This circuit is important because it associates the two wettest and highly persistent weather regimes over Senegal with the driest and the most persistent one. One derivation of this circuit is highlighted, including the two driest regimes and the most persistent one, what can provide important dry sequences occurrence. An exit of this circuit is characterised by a filling of the Saharan heat low. An entry into the main circuit includes a southward location of the Saharan heat low followed by its deepening. The last weather regime is isolated from the other ones and it has no significant impact on Senegal. It is present in June and September, and missing in July and August, meaning that this is a weather regime more specific of the intermediate seasons than the summer. It is included in a large-scale pattern covering the northern latitudes of Europe. The correspondence between these “interannual” synoptic weather regimes and the “pure” synoptic regimes defined in Part I has been established. By selecting a high statistical significance level for these correspondences, each of five out of nine “interannual” weather regimes has a close correspondence with one “pure” synoptic weather regime, one out of them have links with two “pure” regimes, and the last three regimes have no significant correspondence in terms of “pure” regimes. However when considering more moderate links, two out of these three regimes show a connection with a “pure” regime, and the last one remains isolated. The ensemble of the weather regimes occurrences can explain a significant part of interannual variability of summer rainfall amount over Senegal, especially linked to the driest and the wettest weather regimes occurrences. It is also shown that Senegal rainfall state is very sensitive to a small displacement or deformation of the weather regime patterns. 相似文献
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A. K. Gu��ye Serge Janicot A. Niang S. Sawadogo Benjamin Sultan A. Diongue-Niang S. Thiria 《Climate Dynamics》2011,36(1-2):1-18
The aim of this work is to define over the period 1979?C2002 the main synoptic weather regimes relevant for understanding the daily variability of rainfall during the summer monsoon season over Senegal. ??Pure?? synoptic weather regimes are defined by removing the influence of seasonal and interannual time scales, in order to highlight the day by day variability of the atmospheric circulation. The Self-Organizing Maps (SOM) approach, a clustering methodology based on non-linear artificial neural network, is combined with a Hierarchical Ascendant Classification to compute these regimes. Nine weather regimes are identified using the mean sea level pressure and 850?hPa wind field as variables, and gathered into three classes. Two of these weather regimes represent the classical 3?C5-day African easterly waves with a mean wavelength of about 3,000?km. Three others are characterized by a modulation of the semi-permanent trough located along the western coast of West Africa and might be interpreted in terms of the 6?C9-day easterly waves. The last four weather regimes are characterized by a more or less strong north?Csouth dipole of circulation. They can be interpreted as a northward/southward displacement of the Saharan Heat Low for two of them, and a filling/deepening of this depression for the other two. The circulation patterns of all these nine weather regimes are very consistent with the associated anomaly patterns of precipitable water, mid-troposphere vertical velocity, outgoing longwave radiation, and finally rainfall. Rainfall distribution is also highlighted over the southwestern area of Senegal. 相似文献
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Guiming Wang N. Thompson Hobbs Francis J. Singer Dennis S. Ojima Bruce C. Lubow 《Climatic change》2002,54(1-2):205-223
Changing climate may impact wildlife populations in national parks and conservation areas. We used logistic and non-linear matrix population models and 35 years of historic weather and population data to investigate the effects of climate on the population dynamics of elk in Rocky Mountain National Park (RMNP), Colorado, U.S.A. We then used climate scenarios derived from Hadley and Canadian Climate Center (CCC) global climate models to project the potential impact of future climate on the elk population. All models revealed density-dependent effects of population size on growth rates. The best approximating logistic population model suggested that high levels of summer precipitation accelerated elk population growth, but higher summer minimum temperatures slowed growth. The best approximating non-linear matrix model indicated that high mean winter minimum temperatures enhanced recruitment of juveniles, while high summer precipitation enhanced the survival of calves. Warmer winters and wetter summers predicted by the Hadley Model could increase the equilibrium population size of elk by about 100%. Warmer winters and drier summers predicted by the CCC Model couldraise the equilibrium population size of elk by about 50%. Managers of national parks have relied on effects of weather, particularly severe winters, to regulate populations of native ungulates and prevent harmful effects of overabundance. Our results suggest that these regulating effects of severe winter weather may weaken if climate changes occur as those that are widely predicted in most climate change scenarios. 相似文献
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台风西北侧强对流天气浅析 总被引：1，自引：2，他引：1
台前强对流天气过程是较为罕见的.本文通过计算华南地区12站的物理参数以及分析天气形势,并结合台风结构来寻求强对流产生的内外因素.以便为日后的台前天气预报工作服务. 相似文献
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利用1971—2008年柯坪站的地面气象资料及周边气象站的气候整编资料,分析了该地区的沙尘天气变化特征。结果表明:该地区沙尘天气以浮尘为主,扬沙次之,沙尘暴最少;具有明显的季节变化和年际变化,每年3—9月是沙尘天气的多发时段;浮尘年日数近38 a来无明显变化,沙尘暴和扬沙日数呈明显减少趋势;沙尘天气总体分布自东向西逐渐增多。沙尘天气与当地降水量和大风的关系密切,降水偏多的年份,沙尘天气偏少,在吹偏西北风时易出现沙尘天气。 相似文献
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A growing body of research examines the role of extreme weather experience—as one of the most personal, visceral (and increasingly frequent and severe) impacts of climate change—in shaping views on climate change. A remaining question is whether the experience of an extreme weather event increases climate change concern via experiential learning or reinforces existing views via motivated reasoning. Building on this work, we explore the relationship between personal experience and climate change policy preferences using surveys in 10 communities that experienced extreme weather events (3 tornadoes, 3 floods, 2 wildfires, 1 hurricane and 1 landslide). We find that self-reported personal harm aligns with objective measures of event impacts and that personal harm (i.e., experience) is associated with higher levels of policy support. However, we do not find that objective measures of event impacts are related to policy support. Though political ideology (i.e., motivated reasoning) dominates our model of policy support in predictable ways, personal harm moderates this relationship suggesting that conservatives reporting higher levels of personal harm from the event are, on average, more likely to express support for climate policy than those reporting lower levels of harm. We postulate that while extreme weather events may serve as teachable moments on climate change, their lessons may only reach conservatives who feel personally harmed, even in the communities most affected. 相似文献
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Presented is a review of quantitative characteristics of atmospheric frontogenesis that describe it as the process of variations of the vector of the horizontal temperature gradient (both in value and in direction) in an individual particle. The frontogenesis that strives for recovering the thermal wind balance disturbed in the case of inhomogeneous advection, generates vertical circulation which is both thermally direct (warm air ascends relative to cold air) and thermally opposite (upward motions in the cold air). Given are the expressions for computing frontogenesis using the data on temperature, pressure, and wind. Used is the resolution of the frontogenetic vector function into components along the isoline of potential temperature both on and across the constant-pressure surface. The first component describes the change in the temperature gradient vector due to the rotation of isotherms (rotational frontogenesis), and the second component, the variations of the absolute value of the gradient (scalar frontogenesis). Quantitative characteristics of frontogenesis are efficient diagnostic parameters both for understanding weather processes and weather forecast specification and for the verification and enhancement of numerical models. 相似文献
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石家庄的高温闷热天气 总被引：23，自引：4，他引：23
高温闷热是一种灾害性天气，对人们的生活和生产均有很大的影响。针对近几年来石家庄频繁发生的高温闷热天气，对比分析了石家庄市与附近大城市及“三大火炉”城市的温度变化和高温闷热特点，并对干热和闷热者了区别分析，总结了它们出现的天气形势特点。 相似文献