Relations Between Tobacco And Meteorological Conditions In Enshi And Risk Assessment For Meteorological Disasters

Enshi of hubei province is one of its main quality tobacco production areas. Because of climate change, expanded tobacco growing area and plant height up, the influence of such factors as meteorological disasters become an important factor restricting the yield and quality of tobacco leaves. In this paper, the study of tobacco growth dynamic mode by means of computer simulation, combined with the tobacco development of model simulation of tobacco daily development process and the probability of occurrence of meteorological disasters in different reproductive stage for avoiding risks from the time. Based on the theory of natural disaster system, this paper selects environmental sensitivity, vulnerability and the capability of nature disaster prevention and reduction as four factors construct meteorological disaster risk assessment model. Using GIS technology to achieve the tobacco meteorological disaster risk zoning in enshi areas to avoid risk from the space, the research conclusion is as follows:Based on the theory of physiological development time constant and drawing lessons from the rice clock model, this study establishes a comprehensive tobacco growth period model considering the genetic factors and the environmental factors including temperature, photoperiod and precipitation. This model brings in a precipitation factor on the base of the previous models and uses trigonometric functions to simulate the effect of precipitation, so it can describe the influence of precipitation on development progress.According to the tobacco growing period data at different altitudes, the parameters are confirmed by using the Marquardt algorithm, the established model can accurately simulate the development process and predict the growth period of tobacco via the cross validation.To select the initial date of stable over13℃as a tobacco transplanting dates, Used the tobacco growth period model to analyze the frequency of various kinds of meteorological disasters in enshi at different stage of tobacco between the past50years. The results showed that the group tree stage is vulnerable to low temperature damages; Vigorous growing stage is vulnerable to storm; Maturity is meteorological disaster-prone phase, the sorting of frequency is:Torrential rain> consecutive rainfall> high temperature damage> low temperature damage.Using the straight-line moving average method to isolate the trend production and meteorological production based on the enshi tobacco production unit in1988-2009. By the correlation coefficient between meteorological production and meteorological elements, select the key meteorological elements and the key growth period which influence the production of tobacco.Adopt the differential mode quantitative to analysis of the influence of different meteorological disasters on tobacco yield level, using the spine interpolation method to determine the optimal production, Eventually confirms the impact indexes on the optimal production which come from four major meteorological disasters, the indexes of rainstorm, heat injury, cold damage and continuous rain are0.463,0.371,0.165,0.05respectively.According to the meteorological disaster risk assessment model, by using a natural breakpoint method of ArcGIS Enshi tobacco area is divided into five different levels of risk areas, the highest-risk area is located in the northern of Xuan’en; the higher areas include Badang, Hefeng and the rest of Xuan’en; the medium risk areas include Jianshi, Xianfeng, Laifeng and eastern regions of Enshi; the lower risk area is located in the border area of Enshi and Lichuan; Most of lichuan belong to low risk area.