Study On The Relationship Between The Mesocyclone And Strong Convective Storm

Strong convective weather includes hail,short-term heavy precipitation,strong winds,etc.The forecast of strong convective weather has contributed greatly to economic development and people’s lives.Based on the radar data of Tanggu Station in Tianjin from 2005 to 2011,this paper introduces the method of correlation mining of time series,and analyzes the correlation parameters of mesocyclone and strong convection.Finally,it is concluded that the strong convective weather has a close relationship with the mesocyclone,and the forecasting strategy of the convective storm which can produce hail is obtained.The main work of this paper is as follows:Firstly,the radar data of Tanggu Station from 2005 to 2011 in Tianjin was compiled,and the statistical analysis of the season,time and duration of the occurrence of mesocyclone in two strong convective storms,hail and heavy precipitation,was made.The more complete 25 processes were selected,the process was described by a time series of severe convective storm parameters and mesocyclone parameters,and a typical variable analysis algorithm was used to reduce the normalized time series data.The correlation coefficient of the first pair of typical variables is higher than 0.5,it shows that there is a significant correlation between the severe convective storm parameters and the mesocyclone parameters.Secondly,Taking into account the trend of variation between sequences and the influence of local key points,the monotonic features and local extremum features were extracted to symbolize the time series.The symbols in the same period were composed into a transaction set,and the frequent item-sets were found using the Eclat algorithm.In analogy with the learner’s performance metrics,two concepts,positive ratio and inverse ratio,were proposed to evaluate the law of two types of data changes.Experimental results show that there is a significant correlation between the severe convective storm parameters and the mesocyclone parameters.The correlation coefficient of the first pair of typical variables is higher than 0.5.Under the support degree of 0.05-0.3,the running time of the Eclat algorithm is less than 0.7 ms,and the memory occupancy is less than 121 Kb,which are better than both Apriori algorithm and FP-growth algorithm;the positive ratio between the severe convective storm parameters and the mesocyclone parameters is greater than 0.7,which intuitively reflects the similarity degree between the severe convective storm parameter and the mesocyclone parameter and verifies the correctness of the frequent item-sets again.Finally,14 processes,which data and the fact was correct,was found in the severe convective storm from 2005 to 2011,which was divided into isolated class and mosaic class.Combined with the reflectivity factor map,the timing diagrams of the parameters of convective monomer and the mesocyclone,the development process of the convective storm after the occurrence of the mesocyclone was analyzed in detail.And the common features were integrated,experimental results show that the sudden change of the amount of shear of mesocyclone,the combination of monomers and appearance of the overhanging structure have a good indication of the convective storm.Finally,the forecasting strategy of hail convective storm is proposed.In summary,based on the parameters of strong convection monomer and mesocyclone,the evolution relationship between the two was analyzed.At the same time,the strong convective storm process of hail was analyzed in detail,and the forecasting strategy of hail convective storm was proposed,which provides a new idea for the study of strong convective weather.