The Climate Suitability Zoning Method of the Solar Greenhouse in the Northern of China

With the mathematical statistical methods and consideration of the climatic condition requirements of solar greenhouse development, six factors which represent four aspects of light, temperature, wind and snow are chosen as the assessment indices based on the analysis of main climate factors related to solar greenhouse production in the northern of China. They are the total radiation in winter, the number of overcast days in solar greenhouse production season, the average temperature in winter, the annual extreme minimum temperature, the average monthly maximum wind velocity in production season and the average annual maximum snow depth. Then, using weighted index method, an integrated index model of climate suitability zoning is established. Index weights are determined by analytic hierarchy process. And last, a comprehensive climate zoning map of the solar greenhouse development is drawn out with GIS which divides the climatic suitability in this region into four grades: The most suitable, suitable, less suitable and unsuitable. In order to refine the zoning map, Ningxia and eastern Gansu, Henan, Shaanxi with different climatic characteristics in the study area are selected as three typical areas and more detailed climate suitability zoning are carried out, respectively. Results show that for differences of climate resources and their combination conditions, their effects on the development of solar greenhouse are different and weights of the same division index are distrinct in different areas. Fine zonings in typical areas can provide more practical guiding significance in greenhouse production run.In general, the zoning results are in line with the actual situation which proves the selection of index, the division of index threholds and the zoning method reasonable and feasible. At the same time, the quantitative description and complexicy of zoning indexes are realized by AHP and GIS tools. The zoning method not only has solid theory basis, but also is practical. Therefore, this attempt can provide an effective and reasonable way for future research. In addition, some development suggestions are discussed in accordance with the division results, providing reference basis for rationally utilizing climate resourses and adjusting the layout for solar greenhouse development reasonablly.