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1.
Progress in Researches on Ensemble Forecasting of Extreme Weather Based on Numerical Models 总被引：1，自引：1，他引：0
Under the background of climate change, extreme weather events (e.g., heavy rainfall, heat wave, and cold damage) in China have been occurring more frequently with an increasing trend of induced meteorological disasters. Therefore, it is of great importance to carry out research on forecasting of extreme weather. This paper systematically reviewed the primary methodology of extreme weather forecast, current status in development of ensemble weather forecasting based on numerical models and their applications to forecast of extreme weather, as well as progress in approaches for correcting ensemble probabilistic forecast. Nowadays, the forecasting of extreme weather has been generally dominated by methodology using dynamical models. That is to say, the dynamical forecasting methods based on ensemble probabilistic forecast information have become prevailing in current operational extreme weather forecast worldwide. It can be clearly found that the current major directions of research and development in this field are the application of ensemble forecasts based on numerical models to forecasting of extreme weather, and its improvement through bias correction of ensemble probabilistic forecast. Based on a relatively comprehensive review in this paper, some suggestions with respect to development of extreme weather forecast in future were further given in terms of the issues of how to propose effective approaches on improving level of identification and forecasting of extreme events. 相似文献
2.
R K Giri Jagabandhu Panda Sudhansu S Rath Ravindra Kumar 《Journal of Earth System Science》2016,125(4):709-723
In order to issue an accurate warning for flood, a better or appropriate quantitative forecasting of precipitation is required. In view of this, the present study intends to validate the quantitative precipitation forecast (QPF) issued during southwest monsoon season for six river catchments (basin) under the flood meteorological office, Patna region. The forecast is analysed statistically by computing various skill scores of six different precipitation ranges during the years 2011–2014. The analysis of QPF validation indicates that the multi-model ensemble (MME) based forecasting is more reliable in the precipitation ranges of 1–10 and 11–25 mm. However, the reliability decreases for higher ranges of rainfall and also for the lowest range, i.e., below 1 mm. In order to testify synoptic analogue method based MME forecasting for QPF during an extreme weather event, a case study of tropical cyclone Phailin is performed. It is realized that in case of extreme events like cyclonic storms, the MME forecasting is qualitatively useful for issue of warning for the occurrence of floods, though it may not be reliable for the QPF. However, QPF may be improved using satellite and radar products. 相似文献
3.
前期有效降水量是泥石流预报的一个关键因子,但是确定此关键因子的常用方法存在参数取值过于人为主观化的问题。为解决这一问题,提出利用模拟降雨截留、入渗和蒸散发等水文过程的方法确定泥石流预报中的前期有效降雨量,并利用基于流域水土耦合机制的泥石流预报系统预报四川省在2013年7月9日的泥石流灾害来检验该方法。结果表明:利用水文过程模拟方法确定的前期有效降水更适用于泥石流预报,泥石流预报的漏报率比常用的降雨衰减经验公式低21.1%,能更好地为泥石流防灾减灾服务。 相似文献
4.
宁夏降水型地质灾害气象条件等级预警系统 总被引：1，自引：0，他引：1
利用1982-2004年宁夏地质灾害与降水资料,在分析引发宁夏干旱区主要地质灾害的气象条件基础上,采用统计学方法分区建模,建立了宁夏降水型地质灾害潜势预报模型。依据该模型,在可视化高级编程语言DELPHl环境下,研究开发了一套自动化程度较高的降水型地质灾害气象条件等级预警系统;该系统可以通过网络,以协调一致的工作平台,将气象与地质等相关部门有机连接,实现了联合开展地质灾害预报及指导订正的业务流程。根据实时的雨情及降雨预报,依据所建的分区预报模型,对宁夏地质灾害的发生概率进行快速评价,实现对灾害发生的空间范围、强度及其分布概率的自动实时预警预报;通过人机交互订正,提供位图和GEOS（文本）2种格式的概率预报结论,同时实现了预报预警服务材料的自动化输出。2004,2005年的业务试运行表明,该预警系统基本能满足业务的需求,为新业务领域的拓展提供了技术支持。 相似文献
5.
依据甘肃兰州市1955-2010年沙尘暴、 浮尘天气事件年变化资料, 划分年强度分级, 应用Markov模型对其不同强度发生概率进行分析, 在此基础上预测和检验了2011年兰州沙尘暴浮尘天气事件的发生概率.结果显示: 2011年沙尘暴发生的特强年、 强烈年、 强发生年、 一般发生年和少发年的概率为,而事实上2011年发生沙尘暴0次,属于少发年, 符合预测结果; 2011年浮尘天气发生的特强年、 强烈年、 强发生年、 一般发生年和少发年的概率为,而事实上2011年发生浮尘9次,介于平常年和少发年范围, 符合预测结果.随着时间序列的延长, Markov模型可成为短期沙尘暴浮尘天气变化预测的有效途径. 相似文献
6.
In real-time flood warning systems, sufficient lead-time is important for people to take suitable actions. Rainfall forecasting is one of the ways commonly used to extend the lead-time for catchments with short response time. However, an accurate forecast of rainfall is still difficult for hydrologists using the present deterministic model. Therefore, a probability-based rainfall forecasting model, based on Markov chain, was proposed in this study. The rainfall can be forecast one to three hours in advance for a specified nonexceeding probability using the transition probability matrix of rainfall state. In this study, the nonexceeding probability, which was hourly updated on the basis of development or decay of rainfall processes, was taken as a dominant variable parameter. The accuracy of rainfall forecasting one to three hours in advance is concluded from the application of this model to four recording rain gauges. A lumped rainfall-runoff forecasting model derived from a transfer function was further applied in unison with this rainfall forecasting model to forecast flows one to four hours in advance. The results of combination of these two models show good performance with agreement between the observed and forecast hydrographs. 相似文献
7.
随着全球气候变化、自然变迁及陆表生境改变,极端天气频发且呈现出多尺度时空变异特征,对其进行预报和预警一直是气象水文领域关注的焦点。临近预报可较准确地预报未来短时间天气显著变化,是当前预报强降水等极端事件的主要手段。从基于天气雷达0~3 h外推临近预报、融合数值模式0~6 h临近预报的发展历程梳理了临近预报的研究进展,阐述了雷达外推算法的发展进程、雷达外推预报与数值模式预报融合技术进展,指出"取长补短"的0~6 h融合预报在提高降水预报精度、延长降水预见期等多方面有较大的发展潜力,进一步探寻及提升融合技术是未来融合预报发展的核心。将临近预报以气象水文耦合的方式引入水文预报是从源头提高水文预报精度、保障水文预报效果的主要途径,总结了现阶段主流耦合方式、空间尺度匹配技术、水文模型不确定等陆气耦合中的关键问题,阐述了外推临近预报、融合临近预报作为水文预报输入的研究进展,明确了融合临近预报在延长洪水预见期、提高洪水预报精度中存在优势,并讨论了未来的研究重点及发展方向。 相似文献
8.
南京市强降水天气长期动态及变异性规律 总被引：1，自引：0，他引：1
基于南京市1951～2016年汛期(6～9月)各月降水资料,分析研究区强降水天气的长期动态及变异性规律。长期动态结果表明,近66年来南京市强降水天气发生频率显著增加,平均每10年增加0.31次;不同规模强降水中,暴雨、大暴雨天气发生频率均呈增加趋势,其中暴雨天气呈显著增加。多年(7a、10a、15a)月际排序值滑动标准差均通过置信度99%显著性检验,强降水天气变异性呈显著下降趋势;强降水天气汛期盛行月份趋于集中(7月),月间格局趋于稳定,与多年的月际排序值滑动标准差得出强降水天气变异性呈下降趋势的结论相吻合。 相似文献
9.
Heavy off-season rains in the tropics pose significant natural hazards largely because they are unexpected and the popular
infrastructure is ill-prepared. One such event was observed from January 9 to 11, 2002 in Senegal (14.00° N, 14.00°␣W), West
Africa. This tropical country is characterized by a long dry season from November to April or May. During this period, although
the rain-bearing monsoonal flow does not reach Senegal, the region can occasionally experience off-season rains. We conducted
a numerical simulation of the January 9–11, 2002 heavy off-season rain using the Fifth-Generation NCAR/Pennsylvania State
University Mesoscale Model (MM5) and the Weather Research and Forecasting (WRF) model. The objective was to delineate the
meteorological set-up that led to the heavy rains and flooding. A secondary objective was to test the model’s performance
in Senegal using relatively simpler (default) model configurations and local/regional observations. The model simulations
for both MM5 and WRF agree satisfactorily with the observations, particularly as regards the wind patterns, the intensification
of the rainfall, and the associated drop in temperatures. This situation provided the environment for heavy rainfall accompanied
by a cold wave. The results suggest that off-the-shelf weather forecast models can be applied with relatively simple physical
options and modest computational resources to simulate local impacts of severe weather episodes. In addition, these models
could become part of regional hazard mitigation planning and infrastructure. 相似文献
10.
Flood forecasts based on multi-model ensemble precipitation forecasting using a coupled atmospheric-hydrological modeling system 总被引：1，自引：0，他引：1
The recent improvement of numerical weather prediction (NWP) models has a strong potential for extending the lead time of precipitation and subsequent flooding. However, uncertainties inherent in precipitation outputs from NWP models are propagated into hydrological forecasts and can also be magnified by the scaling process, contributing considerable uncertainties to flood forecasts. In order to address uncertainties in flood forecasting based on single-model precipitation forecasting, a coupled atmospheric-hydrological modeling system based on multi-model ensemble precipitation forecasting is implemented in a configuration for two episodes of intense precipitation affecting the Wangjiaba sub-region in Huaihe River Basin, China. The present study aimed at comparing high-resolution limited-area meteorological model Canadian regional mesoscale compressible community model (MC2) with the multiple linear regression integrated forecast (MLRF), covering short and medium range. The former is a single-model approach; while the latter one is based on NWP models [(MC2, global environmental multiscale model (GEM), T213L31 global spectral model (T213)] integrating by a multiple linear regression method. Both MC2 and MLRF are coupled with Chinese National Flood Forecasting System (NFFS), MC2-NFFS and MLRF-NFFS, to simulate the discharge of the Wangjiaba sub-basin. The evaluation of the flood forecasts is performed both from a meteorological perspective and in terms of discharge prediction. The encouraging results obtained in this study demonstrate that the coupled system based on multi-model ensemble precipitation forecasting has a promising potential of increasing discharge accuracy and modeling stability in terms of precipitation amount and timing, along with reducing uncertainties in flood forecasts and models. Moreover, the precipitation distribution of MC2 is more problematic in finer temporal and spatial scales, even for the high resolution simulation, which requests further research on storm-scale data assimilation, sub-grid-scale parameterization of clouds and other small-scale atmospheric dynamics. 相似文献
11.
目前已有大量不同尺度的临界降水标准对区域性滑坡进行预警,但仍存在预警空间外延性差、时间精度低、临界降水阈值不科学等问题。针对当前构建的临界降水阈值实现滑坡预警模型,以云南昭通盘河流域头寨沟为例,在研究区两个不同海拔高度位置分别布设气象站,进行了为期一年的降水观测,并比较了研究区两个不同位置的降水特征。结果表明:研究区降水梯度高达190 mm/hm,两个不同海拔位置降水变异性显著;降水持时是造成山上(2#站)与山下(1#站)次降水量差异的主要影响因素;发生小雨时2#站与1#站的降水差异性很小,但1#站发生中雨及以上的降水事件时,2#站的降水等级比1#站高1~2个等级,且有59.26%的概率会发生大雨或者暴雨;1#站为暴雨时,2#站100.00%概率为暴雨甚至大暴雨;2#站与1#站夜间降水均大于白昼,且强降水事件多发生于夜间。 相似文献
12.
泥石流成因机理的非饱和土力学理论研究 总被引：4，自引：2，他引：4
泥石流是一种具有较强破坏力的自然山地灾害。对于它的预报研究历来为人们所重视，并建立了很多雨量预报模型。然而，这些雨量预报模型的预报时间很短，往往只能在灾害发生前几十分钟作出预报。论文应用非饱和土强度理论对降雨型泥石漉的成园机理进行了研究，提出降雨型泥石流的形成过程可以划分为2个阶段：第一个阶段与前期实效降雨量有关；第二个阶段与短历时强降雨有关。并对各个阶段降雨作用机理以及固体松散物质的力学性质变化特征进行探讨。为预先判断在降雨条件下，会不会发生泥石流以及所需要的降雨量和雨型提供依据。 相似文献
13.
利用呼和浩特市1961-2010年6个国家气象观测站逐小时降水量资料,应用数理统计、滑动平均和M-K突变检验分析了呼和浩特市短时强降水时空分布特。结果表明：呼和浩特市短时强降水频次的空间分布不均匀,主要分布在呼和浩特市南部及山脉迎风坡;呼和浩特市短时强降水具有明显的季节变化和日变化特征,短时强降水频次最高在7月下旬和8月上旬,最容易发生在午后至傍晚,年代和年变化显示20世纪90年代为正距平,1993年之后,呼和浩特市短时强降水次数呈上升趋势,1997年通过显著性检验水平临界线,即呈明显上升趋势,1998年达到峰值。 相似文献
14.
High-impact mesoscale weather events, occurring in different parts of India in all seasons, lead to major weather- and climate-related
disasters. Several research groups and operational weather forecasting centres in India have adopted mesoscale models for
research and operational usage. This paper reviews the work done by different groups with respect to two specific events,
(1) unprecedented locally heavy rainfall near Mumbai (Santa Cruz) on 26 and 27 July 2005 and (2) the Orissa super-cyclone
of 29 and 30 October 1999 from its incipient stage on 24 and 25 October 1999. Considerable variability in the prediction of
the intensity and location of mesoscale heavy rainfall, as well as in the intensity and path of the super-cyclone, are found.
In order to reduce uncertainty in dynamical prediction, it is necessary that the model dynamics, physics, resolution, boundary
conditions and availability of data on land–ocean surface processes are tuned separately to the specific event types, such
as heavy monsoon rainfall, tropical cyclone genesis and movement and severe local thunderstorms, as the processes controlling
such types of events may require suitable treatments for their proper simulations through appropriate dynamics, physics and
resolution. 相似文献
15.
An empirical approach for evaluation of the potential of debris flow occurrence in mountainous areas 总被引：3，自引：2，他引：1
Debris flows can occur relatively suddenly and quickly in mountainous areas, resulting in major structural damage and loss of life. The establishment of a model to evaluate the occurrence probability of debris flows in mountainous areas is therefore of great value. The influence factors of debris flows are very complex; they can basically be divided into background factors and triggering factors. Background factors include the mechanical characteristics of geo-materials, topography and landscape, and soil vegetation; and triggering factors include hydrological and rainfall conditions, and human activities. By assessing the dynamic characteristics of debris flows in mountainous areas, some important influence factors are selected here for analysis of their impacts on the occurrence probability of debris flow. A mathematical model for evaluation of the occurrence probability of debris flows is presented and combined with probability analysis. Matlab software is used for the numerical implementation of the forecasting model, and the influences of rainfall, lithology and terrain conditions on the occurrence probability of debris flows are analyzed. Finally, the presented model is applied to forecast the occurrence probability of debris flows in the mountainous area around Qingping Town; the simulation results show that many loose landslide deposits and heavy rainfall are the key factors likely to trigger debris flows in this region. 相似文献
16.
Experimental real-time multi-model ensemble (MME) prediction of rainfall during monsoon 2008: Large-scale medium-range aspects 总被引：1，自引：0，他引：1
A K MITRA G R IYENGAR V R DURAI J SANJAY T N KRISHNAMURTI A MISHRA D R SIKKA 《Journal of Earth System Science》2011,120(1):27-52
Realistic simulation/prediction of the Asian summer monsoon rainfall on various space–time scales is a challenging scientific
task. Compared to mid-latitudes, a proportional skill improvement in the prediction of monsoon rainfall in the medium range
has not happened in recent years. Global models and data assimilation techniques are being improved for monsoon/tropics. However,
multi-model ensemble (MME) forecasting is gaining popularity, as it has the potential to provide more information for practical
forecasting in terms of making a consensus forecast and handling model uncertainties. As major centers are exchanging model
output in near real-time, MME is a viable inexpensive way of enhancing the forecasting skill and information content. During
monsoon 2008, on an experimental basis, an MME forecasting of large-scale monsoon precipitation in the medium range was carried
out in real-time at National Centre for Medium Range Weather Forecasting (NCMRWF), India. Simple ensemble mean (EMN) giving
equal weight to member models, bias-corrected ensemble mean (BCEMn) and MME forecast, where different weights are given to
member models, are the products of the algorithm tested here. In general, the aforementioned products from the multi-model
ensemble forecast system have a higher skill than individual model forecasts. The skill score for the Indian domain and other
sub-regions indicates that the BCEMn produces the best result, compared to EMN and MME. Giving weights to different models
to obtain an MME product helps to improve individual member models only marginally. It is noted that for higher rainfall values,
the skill of the global model rainfall forecast decreases rapidly beyond day-3, and hence for day-4 and day-5, the MME products
could not bring much improvement over member models. However, up to day-3, the MME products were always better than individual
member models. 相似文献
17.
陆面作为大气运动的下边界,通过动量、热量及物质交换与大气发生复杂的相互作用。陆面过程被认为是影响天气气候的关键过程之一。关于陆面过程对气候的影响已经开展了大量较为深入的研究,相比之下,针对陆面过程对天气的影响研究并没有受到足够的重视。近年来,陆面过程与天气研究也开始受到了越来越多的关注。本文从陆面基本要素、下垫面构成、陆面诱发的局地环流3个方面,回顾了土壤湿度、地形、土地利用、山谷-平原环流等要素和过程对强对流、暴雨、台风、高温热浪等天气事件影响研究的相关进展,以期为今后的研究提供参考。需要指出,尽管此方面的研究已取得了一定进展,但关于陆面过程对天气,尤其是极端(高影响)天气的影响及机制还有待深入研究,进而从陆面过程的角度来理解重要天气形成、发生和发展的机理,从而为数值模式发展和天气预报业务提供更有力的科学支撑。 相似文献
18.
Snow avalanches are a major natural hazard for road users and infrastructure in northern Gaspésie. Over the past 11 years, the occurrence of nearly 500 snow avalanches on the two major roads servicing the area was reported. No management program is currently operational. In this study, we analyze the weather patterns promoting snow avalanche initiation and use logistic regression (LR) to calculate the probability of avalanche occurrence on a daily basis. We then test the best LR models over the 2012–2013 season in an operational forecasting perspective: Each day, the probability of occurrence (0–100%) determined by the model was classified into five classes avalanche danger scale. Our results show that avalanche occurrence along the coast is best predicted by 2 days of accrued snowfall [in water equivalent (WE)], daily rainfall, and wind speed. In the valley, the most significant predictive variables are 3 days of accrued snowfall (WE), daily rainfall, and the preceding 2 days of thermal amplitude. The large scree slopes located along the coast and exposed to strong winds tend to be more reactive to direct snow accumulation than the inner-valley slopes. Therefore, the probability of avalanche occurrence increases rapidly during a snowfall. The slopes located in the valley are less responsive to snow loading. The LR models developed prove to be an efficient tool to forecast days with high levels of snow avalanche activity. Finally, we discuss how road maintenance managers can use this forecasting tool to improve decision making and risk rendering on a daily basis. 相似文献
19.
降雨是诱发坡地地质灾害的重要原因,因此掌握降雨的趋势与分布规律,可有效地用于坡地灾害预警,但由于降雨预测精度、灾害资料统计的不足与坡地地质条件的不确定性,实际应用降雨预警基准仍存在许多困难。通过分析台风诱发坡地地质灾害的降雨特性,来说明降雨预警基准在防灾减灾工作上应用的条件与限制。结果表明,对于不同类型之坡地灾害与降雨分布特性,需采用不同的雨量预警基准。唯有通过岩土力学、工程地质学与气象学的整合研究,才能有效提高降雨预警基准预测的准确率,因此各学科的整合是未来防灾减灾研究工作的发展趋势。 相似文献