Modeling On Simulation Of Plant Canopy Temperature Under Temperature Inversion And Frost Condition

Frost of plant often occur on cloudless night with low atmospheric temperature and air humidity. Upon such condition, the surface temperature falls as a result of its radiation to the space. It causes a sharp reduction in the temperature of the air layer close to the surface. Meanwhile, the upper layer cool down relatively slow leads to atmospheric inversion. The plant canopies is tending to frost as the soil surface froze, which occurs on account of an incremental radiation under that weather, leading to the death of the plant.The plant frost prediction is based on the energy budget among the soil, plant canopies and atmosphere. No consideration of the effect of plant canopies acts on the soil surface is taken to build physical model in current studies that take surface temperature as direct criteria of frost. This paper introduces the plant canopy to "Plant canopy-Soil" interaction model, obtaining the change pattern of soil surface and plant canopies in accord to the time. The result shows the temperature of plant canopy is related to the soil type. With the identical moisture content, the plant canopy of bare soil has a maximum temperature, and that of floury soil has a minimum one, while the temperature of sand soil between them. As the soil has a moisture content of 10%-40%, the increase of moisture leads to a rise of plant canopy temperature, i.e. the moisture content of soil increases by 10%, the temperature of bare soil rises approximately by 1℃.The temperature of surface is higher without plant canopies, while the surface with plant canopies has a higher temperature than that canopies. Usually the temperature difference alters as the time, soil type and moisture content changes rather than a constant value. Therefore, taking the plant canopies temperature as the criteria of frost disaster is much more suitable than assuming the surface temperature is exactly 0℃for the case.