多变量均生函数的正交化筛选方案在季节降水预报中的试验研究     

韩照宇  钱林清 《南京气象学院学报》2000,23(3):422-427

用预报量与多变量预报因子的均值生成函数,通过Ｇｒａｍ－Ｓｃｈｍｉｄｔ正交化使均值生成函数彼此正交,同时利用双评分准则确定入选预报模型的均生函数个数,最后建立山西省季节降水的预报模型。试验结果表明,该模型预报山西省季节降水的效果很好,是一种提高短期区域气候预报水平的可行方法。  相似文献   

西北太平洋台风在S2S时间尺度预报效果评估     

李慧  王晓春  赵立清  钱苏伟 《热带气象学报》2020,36(1):51-59

使用世界气象组织季节内至季节尺度（Subseasonal to Seasonal, S2S）预测项目数据库评估了多个集合预报系统在S2S时间尺度对台风的预报能力。评估的时间段为1999—2010年期间每年5月1日—10月31日。为评估S2S时间尺度台风的预报技巧,使用了台风密集度来描述台风的生成及移动状况。台风密集度定义为一段时间内500 km范围内台风出现的概率。台风密集度由6个S2S集合预报系统后报结果计算得出,它们分别由BoM、CMA、ECMWF、JMA、CNRM和NCEP开发使用。这6个预报系统台风密集度的预报技巧评分表明,当预报时效为11~30天时,ECMWF预报系统的评分为正值,比基于气候状态的参考预报能略好地预报台风。   相似文献   

台湾海峡冬季海面风场数值预报的验证与分析     

郭民权  邢建勇 《海洋预报》2013,30(3)

通过布放在台湾海峡5个浮标冬季(2010年12月至2011年2月)的实测数据对MM5风场的预报结果进行了检验.从空间上看,平潭以北预测风速比实测风速偏高,南部则偏低;随着计算时长的增加,MM5模式预报的平均风速有增加的趋势.通过综合评价检验方法,该模式的短期预报较长期预报效果好.将MM5模式的结果用于台湾海峡冬季平均风场的研究,预测风场和实测风场基本吻合,但台湾海峡靠近台湾一侧模式的平均风速比之前的研究偏小.整体上看MM5较好的体现了台湾海峡冬季风场特点,可以为该区的业务化预报提供参考.  相似文献   

The Entropy Score and its Uses in Earthquake Forecasting   总被引：1，自引：0，他引：1  

David Harte  David Vere-Jones 《Pure and Applied Geophysics》2005,162(6-7):1229-1253

Suppose a forecasting scheme associates a probability p^* with some observed outcome. The entropy score given to this forecast is then –logp^*. This article provides a review of the background to this scoring method, its main properties, and its relationships to concepts such as likelihood, probability gain, and Molchans - diagram. It is shown that, in terms of this score, an intrinsic characterization can be given for the predictability of a given statistical forecasting model. Uses of the score are illustrated by applications to the stress release and ETAS models, electrical signals, and M8.  相似文献   

风云2号卫星红外资料在暴雨数值预报中的应用研究     

刘清  沈桐立 《热带气象学报》2006,22(1):101-104

选取1个暴雨实例，利用统计方法对同期风云2号卫星红外云图资料进行温、湿度反演，通过像素点灰度筛选、灰度反演值订正方法对反演场实施质量控制，并将温、湿度反演场与温、湿度常规分析场实行变分同化。最后为研究反演资料在降水预报中的作用，设计3种引人反演资料的方案与MM5常规方案进行比较，并用TS评分客观评价了上述方案的预报效果。  相似文献   

中尺度数值预报中不同初值方案的检验对比   总被引：4，自引：0，他引：4  

张立祥  陈力强  周小珊  杨森 《气象》2001,27(7):8-12

采用WMO推荐的标准化检验方法对两套初值方案进行检验，一套为使用T106L19全球中期模式预报场作为初猜场的cressman逐步订正客观分析方案（T106）；一套为直接插值客观分析方案（OBS）。通过对比分析发现：（1）反映大尺度环流场的要素，例如，300hPa风场、500hPa高度，T106初值方案略好于OBS。（2）空间尺度较小的要素，例如，850hPa温度、湿度等，OBS略优于T106；在比湿预报场中，低层预报优于高层，但850hPa比湿预报出现正的系统误差，随着预报时效的延长，正系统误差加大。（3）在风场的预报中，低层预报总体不如高层好，U风分量的预报有负的系统性误差，V风分量有正的系统性误差。同时对责任中初值预防的降水进行TS评分，评分结果表明，T106的总体评分高于OBS，但T106初值方案的空报率高于OBS，而OBS初值方案的漏报率高于T106。  相似文献   

地方暴雨增强数值预报模式对江苏地区降水预报能力的检验及分析   总被引：1，自引：3，他引：1  

沈树勤 《高原气象》1996,15(1):84-89

在１９９４年６月中旬－７月中旬期间，江苏省气象台利用地方暴雨增强数值预报模式和实时资料进行了２４ｈ和４８ｈ降水预报业务试验，并对降水预报产品进行了分析和检验，给出了降水预报和实际降水量的对比结果，同时还给出了它们的客观评价值。  相似文献   

Characterization of groundwater contamination using factor analysis   总被引：3，自引：0，他引：3  

C. Subbarao  N. V. Subbarao  S. N. Chandu 《Environmental Geology》1996,28(4):175-180

 The effluent contamination of groundwater at two industrial sites at Visakhapatnam, India, was studied using factor analysis. Thirty groundwater samples near a zinc smelter plant and 19 from the polymers plant were analyzed for specific conductance, chloride, bicarbonate, sulfate, calcium, magnesium, sodium, and potassium. The data were subjected to R-mode factor analysis and the factor scores transferred to areal maps. While magnesium and sulfate are the dominant contaminants at the zinc site, sodium, chloride, and bicarbonate from the effluent are affecting groundwater in the polymers area. Contour maps for each factor suggest the areal extension of the contaminants. Received: 1 March 1995 · Accepted: 18 September 1995  相似文献   

Transnational companies as a source of skill upgrading: The electronics industry in Ho Chi Minh City   总被引：2，自引：0，他引：2  

Ingeborg Vind   《Geoforum》2008,39(3):1480-1493

Employment and training in TNCs constitute a potential route through which FDI-led industrialization can contribute to national and regional development and economic growth. The article explores this link through the case of TNCs in the electronics industry in Ho Chi Minh City, Vietnam. The skill upgrading contribution of TNCs is related to the type of factories located in Vietnam and the role they play in regional production networks using a model combining the reverse product cycle and regional waves of FDI. Most electronics factories in Vietnam are ‘reproduction factories’ with mature technology and a narrow role in basic component manufacturing; it is shown that their contribution to skill upgrading is correspondingly narrow. Training for the majority of employees is very simple, and those who receive additional training do this especially in labour management, not in technical fields. Only a small group of engineers receive advanced technical training, in Vietnam and in the parent company abroad. The best prospects for increased skill upgrading are found in those companies that are more than reproduction factories for assembly; however, such companies are still few. The TNCs also represent a potential contribution to skill upgrading in local firms through supplier linkages and movement of staff, but when they operate in isolation from a local economy with little absorptive capacity, as in this case, this potential is not realized.  相似文献   

基于图像结构的无参考模糊图像及其复原图像质量评价方法     

左博新  明德烈  敖争光  郑文娟 《测绘软科学研究》2008,(1):13-20

针对传统图像的质量评价测度。提出了一种基于边缘检测的无参考模糊图像评价模型。通过测量梯度图像的梯度边缘信息,来评价模糊退化图像和带有模糊效应的复原图像,实验表明：利用本测度所得到的模糊图像质量评价结果与主观评价结果有很好的相关性。本测度较准确地反映了人,对模糊图像质量的主观感受,对于带有模糊效应的复原图像的评价结果也较为符合主观评价结果。  相似文献