吉林省玉米倒伏灾害天气分型及典型过程分析

Weather Classification and Analysis of Typical Processes Leading to Maize Lodging Disasters in Jilin Province

为探求造成吉林省玉米倒伏灾害的天气系统类型、特征及发生规律,利用历史灾情和玉米发育期数据、ERA5再分析资料,采用典型个例分析方法,对吉林省造成玉米倒伏灾害的天气系统进行了分析总结。结果表明:造成玉米倒伏灾害的天气系统主要有台风、东北冷涡、低空切变线及高空槽。玉米拔节—抽雄期倒伏主要受东北冷涡影响,抽雄-乳熟期主要受低空切变线、高空槽影响,乳熟-成熟期主要受北上台风影响。台风是造成吉林省玉米倒伏最为严重的天气系统,影响范围广,其移动路径对作物倒伏灾害的发生范围起决定性作用,倒伏灾害多发生在台风移动路径的西侧或北侧,地面低压系统的北侧。东北冷涡次之,倒伏主要发生在水汽、动力、热力和对流不稳定条件均最为显著的冷涡东南象限。低空切变线、高空槽影响范围小,低空切变线类倒伏发生位置取决于低空切变线或辐合线的位置。高空槽类倒伏一般发生在高空槽前,地面冷锋附近。

In order to thoroughly comprehend the types,characteristics,and patterns of weather systems leading to maize lodging disasters in Jilin Province,an analytical approach employing historical disaster data,maize development period data,and ERA5 reanalysis data is adopted.Utilising typical case analysis methods,we seek to scrutinise and summarise the weather systems associated with maize lodging disasters in Jilin Province.The outcomes indicate that four predominant types of weather systems contribute significantly to maize lodging in the region:typhoon,northeast cold vortex,low-level shear line,and upper trough.During the jointing tasselling period,maize lodging is predominantly influenced by the northeast cold vortex,while during the tasselling milking period,the primary influencing factors are the low-level shear line and upper trough.The milking ripening period is chiefly affected by the northward movement of typhoons.Typhoons emerge as the most severe weather system causing maize lodging in Jilin Province,exhibiting extensive impacts,with the trajectory of their movement playing a pivotal role in determining the extent of crop lodging disasters.Typically,maize lodging disasters triggered by typhoons occur predominantly on the western or northern peripheries of their paths and on the northern flank of the associated surface low-pressure system.The second most influential weather system is the northeast cold vortex.Maize lodging disasters instigated by the cold vortex primarily manifest in the southeast quadrant of its influence,where conditions such as water vapour,dynamics,heat,and convective instability are most pronounced.The low-level shear line and upper trough exhibit a limited influence range.The occurrence site of maize lodging induced by the low-level shear line is contingent upon the positioning of the low-level shear line or convergence line.Maize lodging disasters attributed to upper-level troughs typically manifest in the frontal region of the upper-level trough,proximal to the ground cold front.