飞机积冰预报算法对比及其集成预报模型研究     

卞双双  何宏让  安豪  潘晓滨  张云 《气象》2019,45(10):1352-1362

以人工增雨作业获取的飞机积冰实例资料为基础,利用WRF模式对51次飞机积冰过程进行数值模拟,对比分析了常用七种积冰预报算法对积冰潜势区和强度的预报效果,进而采用评分权重集成法建立了飞机积冰强度集成预报模型,并检验了其预报效果。结果表明:(1)假霜点温度经验法对2002年4月4日积冰个例的预报效果与实况一致,而其他积冰算法预报效果均与实况相差较大;(2)对51次飞机积冰预报效果进行统计检验发现,假霜点温度经验法的预报效果最好,积冰强度预报准确率为72.55%,其次是RAOB法,IC指数法和I积冰指数法次之,改进的IC指数法预报准确率最差,只有19.61%;(3)对比不同积冰算法建立的集成预报模型的预报效果发现,选用IC指数法、假霜点温度经验法、RAOB法进行集成预报时,预报准确率最高,且漏报率、偏弱率及偏强率均能控制在10%以内,比单一预报算法中的最高预报准确率提高了8%,且漏报率降低了4%,偏强率降低了8%。  相似文献   

基于南海北部海区浮游植物吸收光谱斜率变化的粒级结构反演   总被引：1，自引：0，他引：1       下载免费PDF全文

王桂芬  曹文熙  周雯  梁少君  杨跃忠  赵俊 《热带海洋学报》2010,29(2):25-32

浮游植物的粒级结构是一个重要的生物参数。基于南海北部海区不同水体环境下测量的生物光学数据, 作者深入研究了粒级结构对浮游植物吸收光谱的影响。结果表明, 选择443和510nm波段计算得到的浮游植物光谱斜率S对粒级结构的变化具有较高的敏感性, 其随着小型浮游植物比例的增大呈不断增加的趋势。S与水体叶绿素a浓度、浮游植物吸收系数(aph(443))之间表现出明显的正相关特征。以40%为界对不同粒级浮游植物的优势进行定义, 发现在S与叶绿素a浓度、aph(443)的关系分布中小型(Micro)和微微型(Pico)浮游植物占据优势的水体表现出较为明显的分界, 叶绿素a浓度和aph(443)分别在0.70mg•m-3和0.05m-1附近, 相应的S在0.0004(m•nm)-1左右。基于实测数据建立的遥感反射率蓝绿波段比值与S之间的统计关系, 决定系数高达0.91, 为从水色遥感数据反演浮游植物粒级结构提供了重要手段。  相似文献   

Seismic hazard computations for regions with low earthquake activity — A case study for the Belgium,The Netherlands and NW Germany area     

Theo de Crook  Vladimír Schenk  M. S. Barbano  F. Colombo  J. J. Egozcue  M. García-Fernández  P. Kottnauer  G. Leydecker  F. Mantlík  Z. Schenková  G. Zonno 《Natural Hazards》1989,2(3-4):229-236

The algorithms to evaluate seismic hazard, used and/or developed by five teams participating in the TERESA project, applied to the low seismicity area Belgium, The Netherlands and NW Germany are compared. The main differences in the results can be explained by the majority criterion of Egozcue et al. (1989), the differences in the upper bound and zonification and, in some cases, by a higher attenuation.  相似文献   

一种新的地图数据检索方法及其应用软件     

王桥 《武汉大学学报(信息科学版)》1993,(4)

本文提出了一种新的实用地图数据检索方法——“放大镜”式地图数据检索,建立了相应的软件系统,并讨论了该方法的数学基础、软件的特点,还给出了应用实例。  相似文献   

利用GMS－4红外云图资料定量测量淮河流域汛期降水     

傅德胜  尹新怀  徐慧 《南京气象学院学报》1994,(2)

提出和介绍了利用ＧＭＳ－４红外云图资料定量测量淮河流域汛期降水的ＣＴ－ＴＲＣ（ｃｌｏｕｄｔｏｐｔｅｍｐｅｒａｔｕｒｅｒａｉｎｆｕｌｌｃｕｒｖｅ，云顶温度－降水量曲线）方法及实现步骤，并结合个例进行了分析。  相似文献   

ERROR COMPARISON OF WIND FIELD RETRIEVAL FROM SINGLE AND DUAL-DOPPLER RADAR OBSERVATIONS          下载免费PDF全文

Tao Zuyu 《Acta Meteorologica Sinica》1994,8(3):337-345

The error distributions of the wind fields retrieved from single and dual-Doppler radar observations are given inthis paper.The results indicate that the error of dual-Doppler retrieval depends on the position in the scan region of thedual-Doppler radar.The error of single-Doppler retrieval by using velocity azimuth processing(VAP)technique de-pends on the angle between the directions of wind and the radar beam.Generally,the winds retrieved from single Doppl-er radar are close to those retrieved from dual-Doppler radar.But,the error distribution of the single-Doppler retrievalis different from the dual-Doppler retrieval.We simulate the retrievals of single Doppler observation by the use of theoutput wind data from a 3-D numerical model of severe convection.The comparison of the simulated single-anddual-Doppler retrievals shows that the VAP may be a suitable technique for the operational analysis of mesoscale windfields.It can also be used as a supplement to wind field retrieval in the field experiment.  相似文献   

RETRIEVAL OF HORIZONTAL WIND PERTURBATION FIELDS FROM SIMULATED SINGLE DOPPLER RADAR OBSERVATIONS^*          下载免费PDF全文

Gu Songshan  I. Zawadzki  S. Laroche 《Acta Meteorologica Sinica》1994,8(1):89-108

The application of the single Doppler radar dataset analysis is usually confined to the assumption that the actual wind is linearly distributed or uniform locally.Following some dynamic features of convective weather,a conceptual model of moderate complexity is constructed,wherewith a horizontal wind perturbation field is retrieved directly from the single Doppler radar measurements.The numerical experiments are based on a 3-D cloud model-generated convective cell,whose radial velocity component is taken as the radar observations that are put into the closed equations based on the conceptual model to retrieve the horizontal wind perturbation field.After the initial field is properly treated,the retrieval equation is solved in terms of the 2-D FFT technique and the sensitivity to noise is examined.Finally,contrast analysis is done of the retrieved and the cloud model output wind fields,indicating the usefulness of the approach proposed in this paper.  相似文献   

Measurements of solar occulation: the error in a naive retrieval if the constituent's concentration changes     

H. K. Roscoe  J. A. Pyle 《Journal of Atmospheric Chemistry》1987,5(3):323-341

The stratospheric concentrations of many minor constituents change rapidly at sunrise or sunset. If this happens, there is an inherent error when retrieving the vertical profiles of the constituents from measurements of their absorption of sunlight. For retrievals of NO at sunset the error can be estimated from in-situ measurements alone, without appeal to a model of stratospheric photochemistry. Below 20 km this error can approach 100% so that the retrieved NO is zero. But at 40 km, and at 25 km when the absorption is strong and Lorentzian, it can be less than 20%. Precise calculations of the error, even if small, require model calculations of the sunset and sunrise changes. With a model, we have calculated the error for NO, NO₂, OH and ClO.  相似文献   

地图信息的拓扑检索   总被引：2，自引：1，他引：2  

毋河海 《武汉大学学报(信息科学版)》1986,(3)

从本质上看,地图数据处理是一种拓扑变换,即在连续变形(处理)中要保持数据中所内函的不变性(结构特征)。当数据处理系统由拓扑关系所充实与制导时,其智能程度就大为增强,可使其由线性处理演变为非线性处理(关联处理)。根据物体间邻接与关联的强烈程度,可把拓扑关系分为两大类:确定型与模糊型。前者原则上用显式表示,后者则宜用隐式表示。两种表示方式作了简要的对比,並强调隐式结构有着经济性与灵活性的主要优点。同时还强调指出,在建库过程中拓扑信息的人工输入应趋于最少。地理信息的检索可分为两类:常规检索与拓扑检索。对于前者,检索的依据是物体本身的标志,如定性检索与定位检索;而对于后者,检索的依据是物体集合之间的空间关系(如邻接关系、关联关系和包含关系)。实现以常规检索为基础的间接拓扑检索,其实质就是用程序的手段把隐含在数据结构中的所求的拓扑关系借助于两个倒排文件(标题索引与栅格索引)予以显式化。文末介绍了三种典型的间接拓扑检索:基于点集合的拓扑检索,基于线集合的拓扑检索和基于面集合的拓扑检索。  相似文献   

HIRS/2 亮温直接应用于数值预报的试验研究   总被引：7，自引：1，他引：7       下载免费PDF全文

王子厚  王宗皓 《应用气象学报》1995,6(3):273-280

将极轨卫星HIRS/2探测仪的高分辨率亮温资料，经过定标、定位和其它一些预处理后，不经过反演，直接和其它观测资料一起用最优内插(OI)方法进行分析，给出数值预报初始场，并用国家气象中心的准业务有限区预报模式做预报试验。对比试验结果表明，在数值预报中直接使用亮温比使用反演资料更好。  相似文献