关键词: 城市森林, 城市森林

Abstract: Based on the observed data from 2001-2012, analysis showed that the weather situations which caused summer maize lodging in Henan Province could be divided into 2 types: strong cold air type and short-term thunderstorms type. According to the path of cold air, strong cold air type could be divided into central-east type and west type, the scope of summer maize lodging caused by strong cold air may be large, but the intensity was not necessarily serious. Short-term thunderstorms type could be divided into Jianghuai invert trough type and the type of south airflow at the front of warm low pressure. Lodging scope of this type was generally small and local, but very serious. Strong cold air usually caused lodging in August and September, while lodging caused by short-term thunderstorms mostly occurred in July and early August, especially in July. Based on the statistical analysis of 40 cases, the author had built synoptic models about summer maize lodging under 2 different types of weather situations. Generally the scope of strong wind caused by strong cold air were relatively large, if accompanied by heavy rain, large area summer maize lodging would likely to occur, cause greater harm to agricultural production. The author mainly analyzed the atmospheric circulation background and the physical characteristics of a typical example at August 28 and 29, 2009, when a strong cold air caused massive lodging of summer maize. The weather forecast warning index and crop production advice were given in order to help reduce the summer maize lodging.