共查询到20条相似文献，搜索用时 546 毫秒
1.
2.
一次罕见的华南大暴雨过程的
诊断与数值模拟研究 总被引：57，自引：8，他引：49
首先对1994年6月中旬的华南暴雨过程进行了诊断分析,然后,利用PSU和NCAR发展起来的有限区域中尺度模拟系统MM5进行了数值模拟研究。诊断结果表明:此次过程长江以南的大部分地区具备大尺度的降水条件,而在两广地区降水更强,这可能是由地形等其他条件决定的。两广地区活动较强的对流云团是造成暴雨的主要中尺度系统,而东部地区主要是锋面造成的连续性降水,对流活动较两广地区相对较弱。数值模拟结果显示:MM5模式对这次华南的强降水过程具有较好的模拟能力,静力方案对大范围雨区的模拟比非静力方案要好一些,但对大暴雨区的模拟非静力方案似乎更具优越性。对流参数化方案的试验表明,Kuo方案能较好地模拟大范围的雨区,Grell方案对强暴雨中心的模拟似乎比其他方案好。对行星边界层方案的试验显示,边界层过程对强的对流性降水的模拟是不可忽略的。这些看法与已有的诊断结果是相符的。 相似文献
3.
利用1951～2004年计54 a鞍山市逐年春夏季降水资料,采用线性趋势估计法、小波分析方法等统计学方法,分析了鞍山市半个世纪以来春夏季降水的变化特征。结果表明:鞍山市春季降水线性变化趋势为增加趋势,其线性变率为2 mm/10 a,夏季降水线性变化趋势为减少趋势,其线性变率为5 mm/10 a,并且从80年代开始春夏季降水的不稳定性开始增强。春季降水存在着4～6 a和16～18 a的主要变化周期,夏季降水有18～20 a和6～8 a的主要变化周期,各周期变化在不同时期起着主导作用。 相似文献
4.
基于多状态Markov链模式的极端降水模拟试验 总被引：3，自引：2，他引：1
文中建立了基于多状态一阶Markov链的逐日降水量随机模式式结合广义帕雷托分布(GPD)产生夏季逐日极端降水量的模拟资料,结果所显示的各种气候特征表明,绝大多数站点(尤其是中国东部多雨地区)都达到较高的精度.分析表明,该模式对中国东部极端降水特征的模拟能力在某些方面优于两状态一阶Markov链模式.对东部6个代表站模拟试验结果表明,月降水均方差、日降水极大值、月半均降水日数、日降水均方差、日平均降水量等指标与实况比较,均证明该模式对逐日降水量的模拟效果较好,基本模拟出降水量的各种特征.对中同东部78个代表站采用的两种模式模拟结果对比发现,除日平均降水量以外,月半均降水日数、日降水平均极大值都与实际观测结果较为一致,总体上优于两状态模式,说明用该模式在全国范围内模拟逐日降水特征尤其是极端降水特征有较高的町行性.例如,由其中6个代表站模拟资料所拟合的极端降水GPD模式具有较高的拟合优度.无论从门限值或重现期值来看都可发现模拟与实测结果有较好的相似性,且两者门限值的误差越小,重现期极值的差距也越小.证明Markov链模式对极端降水的模拟有广泛的适用性. 相似文献
5.
Chen Lieting 《大气科学进展》1985,2(4):542-548
The relationship between Southern Oscillation (SO) and summer rainfalls in China is further studied by using empirical analyses. Two possible channels for the effects of SO on such rainfalls are proposed. One is mainly brought about by the subtropical anticyclone over the South Pacific through the air-sea interactions ; the other is related to the Australia-Indonesia low pressure trough through the Southern-Northern Hemisphere interaction. 相似文献
6.
P. R. Rakhecha N. R. Deshpande A. K. Kulkarni B. N. Mandal R. B. Sangam 《Theoretical and Applied Climatology》1995,52(3-4):219-229
Summary The Almatti dam is the major engineering feature in the development of water resources in the Upper Krishna river forming a storage reservoir of 6425 million m3 at spillway crest level. In this paper, the design storm rainfalls for different return periods and also the Probable Maximum Precipitation (PMP) for the catchment above Almatti dam have been estimated to review the adequacy of the flood spillway design for the dam. The design storm rainfalls of various return periods have been computed from a statistical analysis of point and areal time series of annual maximum rainfall. In evaluating the PMP, the maximum observed rainfall obtained by Depth Duration method were maximized as the orography of the Western Ghats plays profound influence over the catchment. It was found that (area 35925 km2) the highest areal rainfalls over the catchment were 14.0 cm, 21.5 cm and 24.6 cm in 1, 2 and 3-day durations, respectively. These are scaled up by a factor of 1.23 to obtain the PMP rainfalls. The areal PMP estimates for the upper Krishna River (UKR) catchment above Almatti dam have been found to be 18.0 cm, 27.0 cm and 31.0 cm, respectively.With 6 Figures 相似文献
7.
利用江苏70个基本站多年逐时雨量、相对湿度、风向、风速以及同时段内最低能见度等观测资料,分析不同强度降雨对能见度的影响,并对比分析两种不同强度降雨造成的低能见度事件统计特征。结果表明:降雨是除雾以外,江苏低能见度的主要影响天气(14. 7%),其中稳定性弱降雨和短时强降雨影响最大。与低能见度雾事件不同,降雨造成的低能见度事件全天各时段均可能出现,发生时可伴随较强的风速(2 m/s),短强低能见度多见风速4 m/s(26. 6%)。江苏冬春两季为雨雾高发季,主要受降雨持续时间影响,对应的低能见度区间为500~1 000 m,有明显日变化。短强低能见度主要受雨强影响,多发生于6—9月,对应的低能见度区间为小于200 m,无明显日变化。两种降雨产生的低能见度事件有明显的空间分布差异,且雨雾低能见度发生时偏北风占主导,短强低能见度发生时则偏东风占主导。 相似文献
8.
宁夏春季首场透雨的气候预测探索 总被引：4，自引：0，他引：4
利用目前在统计预报中广泛应用的最优子集回归预报法,作宁夏南部山区及银川地区春季首场透雨出现日期的统计预报,给出了具体的预报方程和拟合效果分析。并对近30 a来宁夏南部山区及银川地区首场透雨出现日期的变化特征进行了较详细的分析。研究结果表明:银川地区3月份出现首场透雨的气候概率为23.3%、4月份为20%、5月份为23.3%、6月份为33.3%,出现机会相对较多。30 a来春季首场透雨出现日期:20世纪70年代相对较晚,80年代偏早,90年代介于70、80年代之间。南部山区春季首场透雨出现时间相对比较集中,其中4月份出现的气候概率为53%,其次是5月份和3月份,分别为20%和17%,最小的是6月份,只占10%,从近30 a来的总趋势看,南部山区春季首场透雨出现日期在波动中略有推迟现象。利用最优子集回归预报法对宁夏春季首场透雨出现日期的预测具有理想的拟合效果。 相似文献
9.
10.
利用1951—2004年我国740站逐日降水资料对夏季长江中下游典型旱涝年季节内振荡周期、强度和位相等特征进行合成对比分析发现:长江中下游涝年降水季节内振荡周期较旱年长, 涝年以30~60 d周期为主, 而旱年以10~30 d周期为主。旱涝年长江中下游地区夏季降水的10~30 d振荡整体上均强于30~60 d振荡; 10~30 d及30~60 d振荡, 涝年的强度都大于旱年。季节内振荡在旱年的北传较涝年强, 能达到50°N附近; 而涝年不仅有明显的季节内振荡从低纬度地区向北传播, 同时还有弱的振荡从中高纬度地区向南传播, 两者汇合于长江流域形成强的振荡中心。影响我国低频降水的低频异常环流分布模态在旱涝年是一致的, 但涝年的低频环流强于旱年, 而这种低频环流场的差异正是造成涝年的低频降水强于旱年的原因之一。 相似文献
11.
K. N. Anakhaev U. I. Makitov Kh. A. Anakhaev A. Kh. Dyshekov 《Russian Meteorology and Hydrology》2016,41(6):418-424
A new method for the assessment of formation conditions of rainfall-generated mudflows is proposed. The method introduces two new criteria: minimum (critical) values of rainfall and meteorological force of rain obtained from the data of observations of rainfalls from 1953 to 2014. This is important for the early warning about the risk of mudflows and for timely taken protection measures in restdential areas and other economic obj ects situated in the zone of the possible negative impact of mudflows. 相似文献
12.
第一次全球大气研究计划试验期间华南
前汛期暴雨过程及其环流特征的诊断研究 总被引：22，自引：6，他引：16
对1979年第一次全球大气研究计划试验(FGGE)期间华南前汛期3次暴雨过程及其环流特征进行了诊断研究。发现：（1）3次暴雨过程均与锋面活动有关,每次锋面过程都与锋生区对应,暴雨多见于锋前暖区内。锋面的特征既不同于冬季的冷锋,又不同于夏季长江流域的梅雨锋。（2）对视热源和视水汽汇作了计算,发现3次暴雨过程中,华南地区的视热源和视水汽汇项有明显作用,积云对流所造成的对流凝结加热作用很重要。（3）华南前汛期暴雨与南海季风有密切关系。1979年FGGE期间南海季风3次向北推进,与3次暴雨过程有直接的联系。（4）对这3次降水过程的水汽来源作了分析,发现除孟加拉湾外,南中国海亦是重要的水汽供应源地。（5）对云系的分析表明,华南上空的β中尺度对流云团为暴雨的发生提供了有利条件。 相似文献
13.
Some features associated with Eastern China Precipitation (ECP), in terms of mean climatology, sea-sonal cycle, interannual
variability are studied based on monthly rainfall data. The rainfall behavior over Eastern China has fine spatial structure
in the seasonal variation and interannual variability. The revealed characteristics of ECP motivate us dividing Eastern China
into four sub—regions to quantify significant lag—correlations of the rainfalls with global sea surface temperatures (SSTs)
and to study the ocean’s pre-dominant role in forcing the eastern China summer monsoon rainfalls. Lagged correlations between
the mid—eastern China summer monsoon rainfalls (MECSMRs) and the global SSTs, with SST leading to rain-fall, are investigated.
The most important key SST regions and leading times, in which SSTs are highly corre-lated with the MECSMRs, are selected.
Part of the results confirms previous studies that show links between the MECSMRs and SSTs in the eastern equatorial Pacific
associated with the El Nino — Southern Oscillation (ENSO) phenomenon. Other findings include the high lag correlations between
the MECSMRs and the SSTs in the high and middle latitude Pacific Ocean and the Indian Ocean, even the SSTs over the Atlantic
Ocean, with SST leading—time up to 4 years. Based on the selected SST regions, regression equa-tions are developed by using
the SSTs in these regions in respective leading time. The correlation coefficient between the observed rainfalls and regressed
rainfalls is over 0.85. The root mean square error (RMSE) for regressed rainfall is around 65% of the standard deviation and
about 15% of the mean rainfall. The regression equation has also been evaluated in a forecasting mode by using independent
data. Discussion on the consistence of the SST—rainfall correlation with circulation field is also presented.
This work was jointed supported by Chinese Academy of Sciences under Grant “Hundred Talents” for “Validation of Coupled Climate
models” and by U.S. Department of Energy under Grant DEFG0285ER 60314 to SUNY at Stony Brook. The authors are grateful to
Professor R. D. Cess at SUNY, Stony Brook for his supports. 相似文献
14.
利用内蒙古113测站1961—2012年6—8月降水资料、1961—2012年NCEP/NCAP再分析资料数据集、国家气候中心太平洋海温资料,采用统计诊断、相关分析等方法,对2012年汛期(6—8月)内蒙古降水特点及影响因子进行分析,探讨2012年汛期(6—8月)内蒙古大范围降水偏多的可能影响因素。通过对近50a汛期降水年际变化特征及海温、印度夏季风活动、中纬度阻塞高压的影响进行分析,结果表明:2012年汛期(6—8月)内蒙古大范围降水偏多,主要表现为降水过程频繁、覆盖范围广、强降水过程多,多站突破历史纪录;主要原因为内蒙古汛期降水在减少的年代际背景下,年际变化规律明显,2012年汛期出现多雨的概率较大;2012年汛期北半球500hPa高度场主要特征相似内蒙古典型多雨年的环流形势;La Nina事件在2012年3—5月结束,有利于汛期降水偏多;印度夏季风异常偏强、乌拉尔山高脊和鄂霍次克海高压偏强、贝加尔湖地区受低槽控制均是影响2012年内蒙古汛期大范围降水偏多的重要因素。 相似文献
15.
Extreme rainfalls in SE South America 总被引：1，自引：0，他引：1
Heavy rainfall trends in a region of south-eastern South America during 1959–2002 were discussed using daily data of 52 meteorological stations of Argentina, Brazil and Uruguay. Changes in intensity and frequency were both studied with different statistical tests and approaches to check the significance of trends of single and regional aggregated rainfall series. There were predominant positive trends in the annual maximum rainfalls, as well as a remarkable increment in the frequency of heavy rainfalls over thresholds ranging from 50 to 150 mm. However, significant positive trends were not shown in the series of annual maximums and shown only in 15% to 30% of the series of frequencies over thresholds. This lack of significance is due to the high variability of heavy rainfalls in space and time, which makes difficult their capture by single rain gauges. Thus, when the assessment of the heavy rainfall indicators of intensity and frequency were conducted at the regional and sub-regional level, it showed significant trends, both in intensity and frequency over thresholds, with a clearer signal in central and eastern Argentina between 30° and 40° S. 相似文献
16.
山东省远距离热带气旋暴雨研究 总被引：22，自引：2，他引：20
应用1971-2003年的山东降水资料、常规天气图资料、台风年签和NCEP资料,对在华南沿海登陆和活动的热带气旋在山东造成远距离暴雨的气候特征进行统计分析,对环流形势场进行合成分析.建立了山东省远距离热带气旋暴雨的天气学模型.分别计算分析了山东有和无远距离热带气旋暴雨合成的水汽和温湿能的收支.结果表明:在华南沿海登陆和活动的热带气旋与西风带环流系统和副热带高压相互作用在山东造成的远距离热带气旋暴雨年均2.5次.暴雨的范围广、强度大.出现暴雨的时间比热带气旋登陆时间滞后.在山东造成远距离暴雨的热带气旋在华南沿海登陆时,中心东部有一股东南风或偏南风低空急流指向内陆.中高纬度中低层西风带环流弱,位置偏北.500 hPa西风带中的偏北气流与副高边缘的偏南气流在山东境内汇合.低层850-700 hPa伴有低值系统影响,山东为气旋性环流控制.热带气旋登陆后其中心附近的中低层偏南风急流向北伸展,绕过副高脊线直达山东.在台风中心附近至山东之间建立起水汽和温湿能的输送通道,把高温高湿的暖湿空气源源不断地向山东输送.在台风登陆后12-48小时内,山东暴雨区上空有大量的水汽和温湿能的净流入.暖湿气流与西风带气流相汇合,产生辐合上升,造成暴雨. 相似文献
17.
基于集合预报的中国极端强降水预报方法研究 总被引：3，自引：1，他引：2
极端强降水天气属于小概率事件,其发生具有很多不确定的因素,预报难度很大。根据Anderson-Darling检验原理研究基于集合预报资料的极端强降水天气预报方法,利用2007—2010年中国T213集合预报资料和2001—2010年6—8月中国降水观测资料,分析观测与集合预报累积概率密度分布函数的特征,建立基于集合预报与模式历史预报累积概率密度分布函数连续差异的数学模型——极端降水天气预报指数(EPFI),并对2011年7月中国极端强降水天气进行预报试验。结果表明,极端降水天气预报指数可以充分利用集合降水累积概率密度分布的尾端信息,为极端强降水提供科学合理的预报,基于中国气象局(CMA) T213集合预报的极端降水天气预报指数可提前3—7 d发出极端强降水预警信号,随着预报时效的延长,预报技巧逐渐降低。研究还表明,模式气候累积概率分布的合理性将直接影响极端强降水天气识别能力。 相似文献
18.
B. E. Peskov A. A. Alekseeva A. E. Nikiforova 《Russian Meteorology and Hydrology》2008,33(10):644-650
The physical-synoptic principles of the automated method of summer precipitation forecasting introduced into operational prognostic practice in 2006 by the decree of the Central Methodical Commission of the Federal Service for Hydrometeorology and Environmental Monitoring (Roshydromet) are presented. Beside that, improved modifications of this method, which are automatically updated, are shown. Validation of those updates based on observational data collected in 2004 has shown improvement of all major criteria of forecasts efficiency. The performed improvement is based on the more detailed quantitative realization of mechanism of various showers formation (including heavy rainfalls). 相似文献
19.
Changes of Accumulated Temperature, Growing Season and Precipitation in the North China Plain from 1961 to 2009 
下载免费PDF全文
下载免费PDF全文 Using the high-quality observed meteorological data, changes of the thermal conditions and precipitation over the North China Plain from 1961 to 2009 were examined. Trends of accumulated temperature and negative temperature, growing season duration, as well as seasonal and annual rainfalls at 48 stations were analyzed. The results show that the accumulated temperature increased significantly by 348.5℃ day due to global warming during 1961-2009 while the absolute accumulated negative temperature decreased apparently by 175.3℃ day. The start of growing season displayed a significant negative trend of -14.3 days during 1961- 2009, but the end of growing season delayed insignificantly by 6.7 days. As a result, the length of growing season increased by 21.0 days. The annual and autumn rainfalls decreased slightly while summer rainfall and summer rainy days decreased significantly. In contrast, spring rainfall increased slightly without significant trends. All the results indicate that the thermal conditions were improved to benefit the crop growth over the North China Plain during 1961-2009, and the decreasing annual and summer rainfalls had no direct negative impact on the crop growth. But the decreasing summer rainfall was likely to influence the water resources in North China, especially the underground water, reservoir water, as well as river runoff, which would have influenced the irrigation of agriculture. 相似文献
20.
长江流域夏季降水及其与海温的滞后相关 总被引：7，自引：0，他引：7
基于月平均台站降水资料分析了中国东部降水的气候特征。由于其降水分布在空间和时间上的复杂性，为便于研究其与海温的关联，特别是海温对降水的影响，根据台站间降水变化在季节变化和年际变化以及与海温相关的一致性，将中国东部区域分成四个子区域。以长江流域的降水为代表，分析了海温对降水的超前相关。给出了主要影响海区和它们的超前时间。综合各影响海区海温和超前时间建立的回归方分析表明：回归降水和观测降水的相关系数大于０．８５。回归的平方根误差是其标准差的６０％和平均雨量的１５％。另外还分析了海温与降水相关与环流变化的一致性。 相似文献