Microclimatic Characteristics under Plastic Film and Relationship with Macroclimate
In order to improve the meteorological service on using of plastic fil m house, some contrast observations on hourly ground temperature and air tempera ture between inside and outside plastic film house were fulfilled in Wuhan, Chin a. Based on the observation, the microclimate characteristic under plastic film was analyzed and some equations about the air temperature and ground temperature under plastic film and various weather conditions were established by using cor relation analysis and stepwise regression analysis. The analyzed results indicat ed that the daily maximum temperature under plastic film or double-layer film wa s correspondingly higher by about 20℃ or 24℃ than that outside in the daylight in clear days. The averaged temperature underplastic film or doublelayer film was correspondingly higher by 0.8～3.5℃ or 3.5～6.5℃ in the nighttime. Becaus e the daily range of temperature change could be about 30～35℃ in clear days, s o that a high temperature damage and a low temperature damage should be both pre vented. Correlation analysis showed that the air temperature under plastic film was highly related to air temperature and solar altitude. The air temperature at night and the ground temperature of 0～10 cm soil layer were also highly relat ed to air temperature. As a result, some equations about the air temperature and the ground temperature under plastic film were established, which can be used t o derive and predict the hourly air temperature and ground temperature accuratel y. These equations can be utilized for the vegetable production meteorological s ervices under plastic film conditions.