排序方式: 共有46条查询结果,搜索用时 15 毫秒
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海上的暴风雨会给水手提供合理的警告:气压计度数下降、风向的突然转变以及天空中某些不祥的预兆都预示着暴风雨即将来临。而地震学家却没有这么幸运。数十载的监测未能提供一次即将来临的地震的任何警报信号,因此,多数地震学家都转而研究其他方面的问题。 相似文献
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中尺度区域内暴雨落区预报的探讨 总被引:1,自引:0,他引:1
以天气学原理和预报员经验为基础,通过对影响宝鸡地区45场暴雨天气的分析,探讨了不同尺度系统对暴雨落区的经向分布与纬向分布的影响。由此建立了暴雨落区的预报模型,对中尺度区域内暴雨落区的预报进行了有益的尝试。 相似文献
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Mesoscale Structure of Rainstorm Retrieved from Dual-Doppler Radar Observations Using the 4DVAR Assimilation Technique 总被引:1,自引:0,他引:1 下载免费PDF全文
The four-dimensional variational (4DVAR) data assimilation method was applied to dual-Doppler radar data about two Meiyu rainstorms observed during CHeRES (China Heavy Rain Experiment and Study). The purpose of this study is to examine the performance of the 4DVAR technique in retrieving rainstorm mesoscale structure and to reveal the feature of rainstorm mesoscale structure. Results demonstrated that the 4DVAR assimilation method was able to retrieve the detailed structure of wind, thermodynamics, and microphysics fields from dual-Doppler radar observations. The retrieved wind fields agreed with the dual-Doppler synthesized winds and were accurate. The distributions of the retrieved perturbation pressure, perturbation temperature, and microphysics fields were also reasonable through the examination of their physical consistency. Both of the two heavy rainfalls were caused by merging cloud processes. The wind shear and convergence lines at middle and lower levels were their primary dynamical characteristics. The convective system was often related to low-level convergence and upper-level divergence coupled with up-drafts. During its mature stage, the convective system was characterized by low pressure at lower level and high pressure at upper level, associated with warmer at middle level and colder at lower and upper levels than the environment. However, a region of cooling and high pressure occurred in the lower and middle levels compared to warming and low pressure in the upper level during its dissipating stage. The water vapor, cloud water, and rainwater corresponded to the convergence, the updraft and the intensive reflectivity, respectively. 相似文献
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Aerosol optical depth(AOD) is the most basic parameter that describes the optical properties of atmospheric aerosols,and it can be used to indicate aerosol content. In this study, we assimilated AOD data from the Fengyun-3 A(FY-3 A) and MODIS meteorological satellite using the Gridpoint Statistical Interpolation three-dimensional variational data assimilation system. Experiments were conducted for a dust storm over East Asia in April 2011. Each 0600 UTC analysis initialized a24-h Weather Research and Forecasting with Chemistry model forecast. The results generally showed that the assimilation of satellite AOD observational data can significantly improve model aerosol mass prediction skills. The AOD distribution of the analysis field was closer to the observations of the satellite after assimilation of satellite AOD data. In addition, the analysis resulting from the experiment assimilating both FY-3 A/MERSI(Medium-resolution Spectral Imager) AOD data and MODIS AOD data had closer agreement with the ground-based values than the individual assimilation of the two datasets for the dust storm over East Asia. These results suggest that the Chinese FY-3 A satellite aerosol products can be effectively applied to numerical models and dust weather analysis. 相似文献
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长治市台大到暴雨短期预报系统柴凤岐,杨万昌,辛黔生(长治市气象局046000)长治市台大到暴雨短期预报系统是在LBMXT/PC286微机上用DBASEⅢ,BASIC语言,模拟预报员的思维方法,对我市春、夏两季24小时大到暴雨预报,从形势分型到结果输出... 相似文献
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WANG Yi HE Bin 《成都理工学院学报》2008,35(1):68-73
The process of transformation of rainfall into runoff over a catchment is very complex and highly nonlinear and exhibits both temporal and spatial "variabilities, In this article, a rainfall-runoff model using the artificial neural networks (ANN) is proposed for simulating the runoff in storm events. The study uses the data from a coastal forest catchment, located in Seto Inland Sea, Japan, This article studies the accuracy of the short-term rainfall forecast obtained by ANN time-series analysis techniques and using antecedent rainfall depths and stream flow as the input information. The verification results from the proposed model indicate that the approach of ANN rainfall-runoff model presented in this paper shows a reasonable agreement in rainfall-runoff modeling with high accuracy, 相似文献
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A mesoscale analysis of heavy rain caused by frontal and topographical heterogeneities on Taiwan Island 总被引:1,自引:0,他引:1
The prevailing mesoscale model MM5 (V3) is used to simulate a heavy rain case caused by interaction between a move-in front and topographical heterogeneities on Taiwan Island. It is found that both thermodynamic and dynamic fields along the front are heterogeneous in time and space. The heterogeneity becomes more significant as the effect of topography is added on. The heterogeneous distribution of physical variables along the front is the main reason for the heterogeneous frontal rain band; the optimum cooperation of the low level and upper level jet is another reason for the development of the rain band.Topography can strengthen the rainfall and causes extremely heavy rain cells. Updraft induced by topography extends to a rather low level, while the uplifted air by frontal circulation can reach to higher levels.The quasi-steady topographic circulation overlaps the frontal circulation when the front moves over Taiwan Island; the advantageous cooperation of various mesoscale conditions causes the large upward velocity on the windward side of the island. 相似文献