Study On Forewarning Technology Of The Disaster From Low Temperature And Spare Sunlight During The Cucumber Growth In Sunlight Greenhouse

Hebei, as a large province of greenhouse vegetable products, where the sunlight greenhouse area has already been amounted to 290,000 hectares until the year of 2009. The disaster that low temperature and spare sunlight occurred in the central and southern regions of Hebei Province, is a major weather hazards to the sunlight greenhouse vegetable growing:The establishment of disaster-warning-system of low temperature and spare sunlight for greenhouse is of great significance for all levels of government or agicultue production departments to grasp the disaster information, to develop disaster prevention measures to minimize the losses caused by disasters, and also important in the both two aspects that the safe production of vegetables and sustainable development of sunlight greenhouse agriculture.Using the method of field test,consecutive four year fixed-point observations of greenhouse microclimate and cucumber growth condition during the autumn-winter and winter-spring crops:Observations involved different weather conditions, different climatic year types, different rotation, observation time included the whole growth period of cucumber, the experimental data with some continuity and integrity accumulated the massive base material for the disaster warning that low temperature and spare sunlight in geemhouse.Based on Greenhouse microclimate data analysis, the results showed that the microclimate difference was large within different weather, different years and different crops, under the autumn-winter season in sunlight greenhouse is larger, every November to next February is the major disaster occuring period.By application of mathematical statistics method, the temperature inside the greenhouse was found significantly relating to temperature outside and the continuous days with spare sunlight, and further the dominant factor is the number of days of continuous spare sunlight radiation; the disaster indicators were determined using hierarchical analysis method, and disaster levels were also measured according reduced production of cucumber, all above these would laid some foundation for the disaster warning services of low tempereture and spare sunlight disaster.The risk rank of disaster occuring in different areas of Hebei province were drawed using diffusion theory analycis. The results showed that central and southern parts of Baoding, central of Shijiazhuang and most of Xingtai, Handan have higher risk of moderate or severe disaser occurrence. Long-term disaster early waring from a risk perspective would provid theoretical basis for sunlight greenhouse vegetable planting, the crop arrangement effectively and ways that how to avoid disaster.By Cluster analysis method, the corresponding situation of the upper air circulation of per occurrence of moderate disaster degree and above have been summarized, the cold low pressure, low pressure tank and Eurasian ridge of circulation were major three kinds, as long as the circulation meets one of three condition, a medium-term disaster warning can be predicted.According to the current disaster degree and future 1-5 days weather forecast, the degree of hazard of low temperature an spare sunlight could be determinded to achieve short-term disaster warning. Using vc++language, C/S mode framework and SQL SERVER database, disaster warning service system of low temperature and spare sunlight for greenhouse was established including disaster monitoring, early warning, assessment, service measures and other functions, when the future weather conditions meet disaster indicators, the system would automatically generate disaster warning information, to achieve the automation of disaster early warning. And through business applications, the system runs well.As an important part of the national "Vegetable Basket Project", Sunlight greenhouse vegetable production has become the important way of income increase for famers, with remarkable economic and social benefits. With the expanding of planting area and introduction of new development, Sunlight greenhouse vegetable production not only need higher management technology but also more stringent requirements for regulation of the weather and climate conditions. Strengthening the early disaster warning of low temperature and spare sunlight and other meteorological disaster has wide application prospects in mproving the vegetable production efficiency and limitation of disaster prevention and mitigation.