共查询到20条相似文献，搜索用时 62 毫秒
1.
2.
以大汶河流域为研究区域,利用自动站雨量数据、数值预报雨量数据、雷达基数据等气象资料,建立以TOPMODEL模型为核心的暴雨山洪预报模型,模拟暴雨发生时山洪的产生及变化,预报山洪发生的规模和时间,再根据流域不同历史重现期的面雨量值,实现山洪监测预警。具体作法:将大汶河流域拆分成90m×90m的网格点,依据8邻域汇水理论模拟每个网格点内水流情况,并根据汇水与地理信息,将全流域划分为三级,降低由于降雨和下垫面的空间不均匀性对模拟结果带来的影响;利用时间叠加和滞后性实现对山洪的预报,并应用数值预报精细化雨量产品,进一步修正山洪预报结果,延长山洪预报时效;计算各子流域不同历史重现期的面雨量值,将其作为致灾阈值,实现各子流域的分级报警;另外,采用概率配对法确定雷达反射率与降雨量的关系实现雷达估测降水,对自动站模拟山洪的方法进行有效的补充,提高系统的业务可用性。 相似文献
3.
4.
5.
三种数值预报产品在清江流域面雨量预报中的应用检验 总被引：3，自引：3，他引：0
以2003年主汛期(6—8月)清江流域逐日面雨量为预报对象,采用自行开发的“数值预报产品分流域面雨量客观预报应用系统”的运行结果,对T213、MAPS、MM5等几种数值降水预报产品进行了一般性预报、定量误差值及重要降水过程预报的检验。通过这一检验分析,旨在加深对几种数值降水预报产品在清江面雨量应用中的认识,也为日常降水预报提供参考。 相似文献
6.
以T213模式、HLAFS模式、MM5中尺度模式输出的格点资料以及日本降水量格点资料为基础，研究了面雨量的计算方法和预报方法；根据各种数值模式输出的降水量预报性能和质量优劣特点，依据数值模式的形势场预报优于要素场预报的现实，构造了在不同环流形势背景下，启动不同预报方程的面雨量预报业务流程，有效的遏止了在环流形势调整时预报输出不能快速响应的弱点，提高了点和面雨量预报的准确度，并建立了“山西省主要河流流域面雨量预报业务系统”。2003年将该预报系统投入业务运行，取得了良好的预报服务效果。 相似文献
7.
GRAPES模式在淮河流域面雨量预报中的应用 总被引：4，自引：1，他引：4
利用我国新一代数值预报模式GRAPES输出的降水预报，制作了2005年7—9月淮河流域的面雨量预报，并对其与预报员制作的面雨量预报和面雨量实况进行了对比分析。期间7月4—11日、7月27日-8月4日淮河流域分别出现了两段集中强降水时间，给各地造成了严重的洪涝损失，因此针对这两次强降水过程着重进行了分析和讨论，同时进一步利用安徽省高密度自动雨量站资料对流域面雨量的估测和预报进行了初步研究。结果表明：用GRAPES模式产品直接制作的淮河流域面雨量预报产品在实际工作中具有较高的参考价值；高密度雨量站资料的使用有利于提高面雨量实况估测的精度，更客观地检验面雨量预报产品。 相似文献
8.
本系统以T213数值预报产品降雨量为基础,采用泰森多边形法计算资阳区域内及其以上沱江流域的面雨量,根据统计得出的面雨量总量与洪涝的关系,实现了区域洪涝情况的监测和趋势的预报。 相似文献
9.
本系统以T213数值预报产品降雨量为基础,采用泰森多边形法计算资阳区域内及其以上沱江流域的面雨量,根据统计得出的面雨量总量与洪涝的关系,实现了区域洪涝情况的监测和趋势的预报. 相似文献
10.
利用多普勒雷达资料作站点雨量及面雨量临近预报 总被引：7，自引：5，他引：2
通过对近两年收集的降水过程的雷达回波资料进行统计分析,得到本地区主要降水过程类型及其回波演变特征;利用反射率因子的基数据和风廓线产品数据等资料,运用交叉相关法计算区域速度、读取风廓线得到环境风速度,自动判别降水回波类型、识别回波整体及单体移动速度;应用本地实时的dBz-I关系及线性外推法计算未来1～2 h站点降水量及面雨量,实现降水临近预报自动化;应用自动站雨量资料及雷达联合自动站资料所作的雨强实时分析场对1 h站点雨量预报及区域雨量预报进行初步检验,1～24.9 mm和≥25 mm以上站点预报的平均相对误差分别为58%、33%;区域雨量预报的雨区范围及中心分布与实况具有较好的一致性;2 h降水预报在回波较稳定时,仍有较好的预报效果. 相似文献
11.
2007年1月,全国平均气温为-4.5℃,比常年同期偏高1.4℃;全国平均降水量为11.1mm,较常年同期(12.1mm)偏少.月内,我国长江中下游地区出现大范围雨雪天气,湖北、安徽遭受雪灾;我国东部地区出现大雾天气,部分地区交通受到影响;云南西南部干旱缓和,华北、辽宁、广西、西藏干旱发展;26-27日北方地区出现今年第一次沙尘天气;长江以南地区多阴雨天气. 相似文献
12.
新疆维吾尔自治区气象局气象台 《大气科学》1978,2(1):28-37
木文分析新疆‘水’旱年度前冬11月至当年6月间北半球中高纬度500毫巴月平均环流波型及逐日超长波的演变特征。在新疆冬春干旱少雨(雪)月份,500毫巴中高纬度环流波型与北疆气候上降水量最少的元月份的平均波型相似,即半球内盛行大西洋东部,西西伯利亚和东北太平洋三个波脊。而多雨(雪)月份,往往相似于北疆气候上相对多雨的11月和5月份的平均波型,半球内盛行欧洲(偏西或偏东)和美洲西岸两个波脊。这种平均槽脊主要是各超长波的稳定及其演变的综合结果。造成新疆季节性‘水’旱异常的长期天气过程,分别表现在欧洲(对应多雨)和乌拉尔—西西伯利亚(对应少雨)两地区,有数次(通常为2～4次)准静止的超长波脊接连替换的过程,造成亚欧环流长时期的相对稳定。 在研究上述准静止超长波脊替换过程的演变时,我们又注意到500毫巴极地高压的活动情况,发现上述欧亚准静止超长波建立和替换的过程,大致可归纳为“北太平洋高压分裂单体西退并入型”、“大西洋高压分裂单体东移并入型”和“上游效应型”三种基本类型。并且提出,前两类基本过程,可能是欧亚准静止超长波脊建立或替换,亦即异常环流长期稳定的一种天气学判据。 相似文献
13.
《Dynamics of Atmospheres and Oceans》1999,29(2-4):365-395
We present definitive observational evidence that the startling change of the Eastern Mediterranean deep circulation observed in winter 1995 and documented by [Roether, W., Manca, B.B., Klein, B., Bregant, D., Georgopoulos, D., Beitzel, V., Kovacevich, V., Luchetta, A., 1996. Recent changes in the Eastern Mediterranean deep water. Science 271, 333–335.] actually started before October 1991. This change involved not only the deep water mass pathways but also the origin and pathways of the water mass spreading in the intermediate layer. We carry out the first unified analysis of the POEMBC-O91 data set, which shows that, differently from the previous decade of the 80s, the Cretan/Aegean Sea was in 1991 the `driving' engine of the intermediate, transitional and deep layer circulations, with Cretan Intermediate Water (CIW), transitional water and Cretan Deep Water (CDW) spreading out from the Cretan Sea into the basin interior. The most important new results are: (a) the Levantine Intermediate Water (LIW) formed inside or at the periphery of the Rhodes gyre is blocked in its traditional westbound route on its density horizons σθ=29.05 and 29.10 kg/m3 by a three-lobe strong anticyclonic structure in the Southern Levantine, which induces a substantial LIW recirculation in the Levantine basin itself; (b) the CIW exiting from the Western Cretan Arc Straits spreads into the Ionian interior on the σθ=29.05–29.10 kg/m3 isopycnal surfaces, thus replacing the LIW confined in the Levantine basin. A branch of CIW flows eastward in the Cretan passage and is entrained by the Ierapetra anticyclone to flow again into the Cretan Sea through the Eastern Cretan Arc Straits; (c) on the horizons σθ=29.15 and 29.18 kg/m3 a transitional water mass of Cretan origin, denser than CIW, and CDW are observed to spread out massively from the Cretan Arc Straits both into the Ionian and Levantine interiors. These isopycnal surfaces rise to much shallower depths in 1991 than in 1987, increasing the salt content of the intermediate, transitional and deep layers. This leads to a massive salt increase in the Ionian below 1200 m, clearly related to lateral advection of the new denser waters of Cretan/Aegean origin, thus contradicting the hypothesis of a vertical salt redistribution proposed by Roether et al. 相似文献
14.
湿大气的广义位温与干大气位温及饱和湿大气相当位温的比较 总被引：5，自引：1，他引：4
实际大气既非完全是干空气,也不是处处达到饱和的湿空气,而是处于含有水汽但又不饱和的湿空气状态。基于这样一种湿大气状态,在湿大气中广义位温定义的基础上,对不同暴雨类型的广义位温与干大气的位温及饱和湿大气的相当位温做了比较。对2003年江淮流域暴雨过程、2004年华北一次暴雨过程以及2006年碧利斯台风中的位温、相当位温和广义位温分布的对比分析表明:即使是在暴雨系统中,湿空气的相对湿度也不一定达到100%,饱和湿空气相当位温的引入条件不能完全满足。而广义位温的定义用一个表达式就可以表示出于大气、未饱和湿大气以及饱和湿大气这3种大气状态的位温,位温和相当位温则是广义位温的特殊情况。当大气比湿为零时,广义位温就变成位温;当大气比湿达到饱和后,广义位温就变成相当位温。除了可以衔接干大气位温和饱和湿大气的相当位温外,广义位温包含了水汽由干到湿再到饱和的变化过程,更好地体现了大气中水汽的实际分布和变化特征。 相似文献
15.
2008年11月,全国平均气温为2.9℃,较常年同期(2.1℃)偏高0.8℃.全国平均月降水量为24.7mm,较常年同期(18.0mm)偏多6.7mm;湖南、贵州区域平均降水量为1951年以来历史同期最多,广西为第二多;河北为第二少. 相似文献
16.
In this study, satellite-derived outgoing longwave radiation (OLR) and the reanalysis from the National Centers for Environmental
Prediction/National Center for Atmospheric Research are used as verification data in a study of intraseasonal variability
in the Goddard Laboratory for Atmospheres (GLA) and the United Kingdom Meteorological Office (UKMO) atmospheric general circulation
models. These models simulated the most realistic intraseasonal oscillations (IO) of the 15 Atmospheric Model Intercomparison
Project models previously analyzed. During the active phase of the intraseasonal oscillation, convection is observed to migrate
from the Indian Ocean to the western/central Pacific Ocean, and into the South Pacific Convergence Zone (SPCZ). The simulated
convection, particularly in the GLA model, is most realistic over the western/central Pacific Ocean and the SPCZ. In the reanalysis,
the baroclinic structure of the IO is evident in the eddy-stream function, and eastward migration of the anticyclone/cyclone
pairs occurs in conjunction with the eastward development of convection. Both the GLA and UKMO models exhibit a baroclinic
structure on intraseasonal time scales. The GLA model is more realistic than the UKMO model at simulating the eastward migration
of the anticyclone/cyclone pairs when the convection is active over the western/central Pacific. In the UKMO model, the main
heating is located off the equator, which contributes to the irregular structures seen in this model on intraseasonal time
scales. The maintenance and initiation of the intraseasonal oscillation has also been investigated. Analysis of the latent
heat flux indicates that evaporative wind feedback is not the dominant mechanism for promoting the eastward propagation of
the intraseasonal oscillation since evaporation to the west of the convection dominants. The data suggest a wave-CISK (conditional
instability of the secondkind) type mechanism, although the contribution by frictional convergence is not apparent. In the
GLA model, enhanced evaporation tends to develop in-place over the west Pacific warm pool, while in the UKMO simulation westward
propagation of enhanced evaporation is evident. It is suggested that lack of an interactive ocean may be associated with the
models systematic failure to simulate the eastward transition of convection from the Indian Ocean into the western Pacific
Ocean. This hypothesis is based upon the examination of observed sea surface temperature (SST) and its relationship to the
active phase of the intraseasonal oscillation, which indicates that the IO may evolve as a coupled ocean-atmosphere mode.
The eastward propagation of convection appears to be related to the gradient of SST, with above normal SST to the east of
the convection maintaining the eastward evolution, and decreasing SST near the western portion of the convective envelope
being associated with the cessation of convection.
Received: 13 September 1996/Accepted: 14 April 1997 相似文献
17.
北非地区海-陆热力差异与夏季江淮流域旱涝的关系 总被引：3，自引：1，他引：2
基于NCEP/NCAR月均再分析资料和中国743站降水资料,根据夏季江淮流域51 a(1954-2004年)区域旱涝指数的年代际变化特征,确定北非地区作为研究的关键区.分析发现,关键区的地表温度异常在冬季具有较好的持续性,冬季北大西洋涛动是导致这种异常持续性的重要原因之一.通过对前冬北非地区地表温度和夏季江淮流域降水的SVD分析发现:当北非大陆地区偏冷,其西北侧的海区偏暖时,江淮流域夏季的降水将整体偏多;反之,江淮流域夏季的降水整体偏少.进一步研究发现,北非地区海陆地表温度异常的对比,要比其中单一海洋或陆地区域的异常对夏季江淮流域的旱涝有更好的指示能力.文中定义了一个海陆热力差异指数来表征这种地表温度异常的对比程度,该指数和夏季江淮流域旱涝指数呈较好的正相关关系,并且对夏季江淮流域极端旱涝年份也有较好的指示,认为该指数可以作为一个指示江淮流域整体旱涝事件的预报因子. 相似文献
18.
The Tornado and Storm Research Organisation (TORRO) was formed in the UK in 1974 in order to determine realistic spatial, temporal and intensity distributions of tornadoes in the UK and, eventually, throughout Europe. Currently, TORRO's databases contain nearly 2000 tornadoes and over 550 waterspouts for the UK alone. In 1972, TORRO's founder, Terence Meaden, devised the Tornado Intensity Scale. This scale enables the wind speeds of tornadoes to be rated on a scale from T0 to T10, or more (since it is an open-ended scale). Using this scale, estimates have been made of the statistical return periods of differing intensities of UK tornadoes. TORRO's research into understanding the conditions of tornado development is ultimately intended to lead to issuing forecasts of tornadoes. In 1991, TORRO issued the first tornado watch in the UK for 12 November and this proved to be accurate—not only did three property-damaging tornadoes strike East Anglia but the forecast maximum intensity of T5 was attained. In 1975, TORRO expanded its activities to include conventional thunderstorm reporting and investigations. In 1982, TORRO incorporated the British and Irish thunderstorm data-collection organisation, the Thunderstorm Census Organisation (TCO), which was established in 1924. By the early 1980s, TORRO's network of voluntary thunderstorm observers, located throughout the UK and Ireland and increasingly in other European countries, numbered around 350 and the network continues to grow. In addition to TORRO's early focus on tornadoes and thunderstorms, its data collection and research has expanded to consider other whirlwinds (such as waterspouts and land devils), hailstorms, lightning (including ball lightning) and blizzards/heavy snowfalls. In 1996, TORRO began providing easy access to its databases (e.g. post-1995 UK and European severe weather events, especially tornadoes and hailstorms) and other information via its internet site at http://www.torro.org.uk/. Building on over 25 years of experience—and of the half a century of the TCO before it—TORRO continues to expand its European role in severe weather data collection and research, helped by the on-going appointment of European representatives and its increasing European membership. 相似文献
19.
利用NCEP/NCAR再分析月平均资料和中国160站降水资料，分析了1951～2000年间5月青藏高原主体、高原东部和高原西部（90°E分界）地表温度的变化特征及其与江淮地区夏季降水的关系。结果发现:在研究高原热力异常对我国江淮地区夏季降水的影响时，要考虑到高原热力状况的空间差异对其的影响。相关分析发现，与高原主体和高原西部相比，高原东部地表温度变化对7月江淮地区的降水有更好的指示性。高原东部和其以北区域的大尺度热力差异比高原本身的热力异常对江淮地区夏季降水有更好的指示意义，可以作为我国江淮地区夏季降水的一个预报因子。 相似文献
20.
四川重庆遭受暴雨袭击 黑龙江广西等地有旱情——2004年9月 总被引：3，自引：0，他引：3
9月份，全国大部地区降水量接近常年同期或偏少，全国大部地区气温接近常年同期或稍偏高。四川、重庆等地出现大到暴雨、局地大暴雨，达州、开县等地降水量超同期历史极值。洪涝及强降水诱发滑坡、泥石流等灾害造成重大人员伤亡和财产损失；0421号热带风暴海马和第6号热带低压在我国登陆；黑龙江东北部、广西北部等地存在旱情；山东、甘肃、湖北等省局地遭受冰雹、雷击等强对流天气袭击。 相似文献