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Following previous studies of the rainfall forecast in Shenzhen owing to landfalling tropical cyclones(TCs), a nonparametric statistical scheme based on the classification of the landfalling TCs is applied to analyze and forecast the rainfall induced by landfalling TCs in the coastal area of Guangdong province, China. All the TCs landfalling with the distance less than 700 kilometers to the 8 coastal stations in Guangdong province during 1950—2013 are categorized according to their landfalling position and intensity. The daily rainfall records of all the 8 meteorological stations are obtained and analyzed. The maximum daily rainfall and the maximum 3 days' accumulated rainfall at the 8 coastal stations induced by each category of TCs during the TC landfall period(a couple of days before and after TC landfalling time) from 1950 to 2013 are computed by the percentile estimation and illustrated by boxplots. These boxplots can be used to estimate the rainfall induced by landfalling TC of the same category in the future. The statistical boxplot scheme is further coupled with the model outputs from the European Centre for Medium-Range Weather Forecasts(ECMWF) to predict the rainfall induced by landfalling TCs along the coastal area. The TCs landfalling in south China from 2014 to 2017 and the corresponding rainfall at the 8 stations area are used to evaluate the performance of these boxplots and coupled boxplots schemes. Results show that the statistical boxplots scheme and coupled boxplots scheme can perform better than ECMWF model in the operational rainfall forecast along the coastal area in south China. 相似文献
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In this paper,the observational data from Marine and Meteorological Observation Platform(MMOP)at Bohe,Maoming and buoys located in Shanwei and Maoming are used to study the characteristics of air-sea temperature and specific humidity difference and the relationship between wind and wave with the tropical cyclones over the South China Sea(SCS).The heat and momentum fluxes from eddy covariance measurement(EC)are compared with these fluxes calculated by the COARE 3.0 algorithm for Typhoon Koppu.The results show that at the developing and weakening stages of Koppu,both these differences between the sea surface and the near-surface atmosphere from the MMOP are negative,and data from the buoys also indicate that the differences are negative between the sea surface and near-surface atmosphere on the right rear portion of tropical cyclones(TCs)Molave and Chanthu.However,the differences are positive on the left front portion of Molave and Chanthu.These positive differences suggest that the heat flux is transferred from the ocean to the atmosphere,thus intensifying and maintaining the two TCs.The negative differences indicate that the ocean removes heat fluxes from the atmosphere,thus weakening the TCs.The wind-wave curves of TCs Molave and Chanthu show that significant wave height increases linearly with 2-min wind speed at 10-m height when the wind speed is less than 25 m/s,but when the wind speed is greater than 25 m/s,the significant wave height increases slightly with the wind speed.By comparing the observed sensible heat,latent heat,and friction velocity from EC with these variables from COARE 3.0 algorithm,a great bias between the observed and calculated sensible heat and latent heat fluxes is revealed,and the observed friction velocity is found to be almost the same as the calculated friction velocity. 相似文献
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随着数值模式的升级，数值预报产品越来越具可用性，它不仅为业务预报提供了定量化的参考，而且弥补了资料在某些区域和某时次的空缺；数值预报模式还可以提供大量的物理量，有助于天气分析和预报。因此，数值预报产品越来越受预报员欢迎，但是由于数值预报模式提供的产品很多，如何利用好这些产品就成为一个重要的课题，数值预报产品的释用研究因而愈显重要。目前大量的预报中多采用PPM和MOS这两种统计释用方法。PPM是用过去的因子实测资料和预报量建立统计关系，而后用数值预报输出的因子资料代人方程中得到预报值，这样处理的缺点是… 相似文献
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刘春霞 《热带气象学报(英文版)》2002,8(1):93-103
Climatological laws are studied for the annual frequency of tropical cyclone occurrence and the date of the yearly first landfall,which take place in the Guangdong province or pose serious threats on it from 1951 to 1999,using the data in the Yearly Book on Typhons.A new method that has developed over recent years for the study of temporal sequences,the wavelet analysis,is used,in addition to more common statistical approaches.By analyzing two wavelet functions,HAT and MORLET,we have compared the results of transfor proaches.By analyzing two wavelet functions,MHAT and MORLET,we have compared the results of transformation of the wavelets provided that ther conditions remain unchanged.It is discovered that the variance of MORLET wavelet has better indication of primary periods; period-time sequence charts can reflect major affecting periods for individual sections of time;when compared with the orginal sequence,the chart shows a little shift.On the other hand,such shift is absent in the MHAT wavelet.but its higher frequency part of variance covers up the primary periods to make its variance less pedominant as compared to the MORLET wavelet.Besides,the work compares two different assumptions of an amplifying factor a.It is found that primary periods can be shown more clearly in the variance when a takes the exponential of 2 than it takes values continuously.Studying the annual frequency of tropical cyclones and the date of first appearance for periodic patterns ,we have found that the primary peroids extracted by this approach are similar to those obtained by wavelet transformation. 相似文献
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基于站点观测数据的气温空间化方法评述 总被引：1，自引：0，他引：1
基于统计学的插值方法是地理学、生态学领域研究气温空间化的主要方法之一,对获取精细化气温数据进行生态模拟具有重要意义。结合国内外气温空间插值的主要研究成果,对常用气温空间化方法进行了归纳、对比,探讨各种方法的适用性和不足之处,从而为涉及气温空间化的具体研究提供一定的参考,并探讨了各类方法优化的方向。不同方法的对比分析结果表明:各种气温空间化方法各有所长,在具体的应用中都取得过较好的效果,但并不存在普适性的方法,在实际应用时必须针对研究区域具体的地理特征进行方法适用性验证或对各类方法中的具体参数进行改进,才能实现区域气温的空间最优化模拟。根据气温场的物理分布特征,结合GIS技术,考虑地形等更多的相关因子以提高气温分布微观细节的模拟精度是未来重要的发展趋势。 相似文献
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华南近海两浮标点的波浪特征分析 总被引：2，自引：0，他引：2
基于汕尾和茂名海域2个近岸浮标连续1年的风、浪观测数据,分析了有效波高等参量的月统计特征,并检验了多种风-浪经验关系.统计显示：2个浮标点的波浪有共同特征,如波高都具有明显的冬半年与夏半年特征.冬半年浪较大,其中茂名点有效波高中值在1.3～2m之间,汕尾点有效波高中值在1～1.5m之间;夏半年浪较小,两浮标点有效波高均在1 m以下.2点的波浪也存在差异,如汕尾点波浪在9月份至次年3月份呈冬半年特征,而茂名点则从10月份至次年3月份呈冬半年特征;汕尾点波向呈向岸特征,而茂名点则无此特征.风-浪经验关系检验结果显示,不同经验关系的集合预报结果可较好地与实测值吻合,并分析了产生离群值的因素. 相似文献
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运用1980-2002年5-8月GMSTBB候平均资料，经过统计分析得到：南海和东亚候夏季风活动指数定义为候平均TBB≤273K；其强度分为3级，即弱季风为268K〈TBB≤273K，一般季风为263K〈TBB≤268K，强季风为TBB≤263K。与此同时，还给出了运用TBB候距平帮助判识季风强度的分析方法。运用该季风指数，统计分析了上述各年季风初始爆发日期和各年各月季风活动情况。另外，还对比分析了1998年长江中下游地区暴雨和1994年华南暴雨2个典型暴雨灾害年季风活动，展示了候季风活动与暴雨期间各暴雨过程之间的密切关系。 相似文献