Temporal and Spatial Distribution Characteristics of Near Ground Temperature in Tea Farm Under Temperature Inversion in Early Spring

In order to protect tea plants from frost damage in early spring,it is necessary to know temporal and spatial distribution characteristics of near ground temperature under temperature inversion.Horizontal distribution of temperature at tea plant canopy,diurnal change in ground temperature and vertical distribution of temperature within 7 m above ground was monitored in tea fields on flat land,and slopes different in exposure(north and south).Results show that in early spring,when the weather is clear,the diurnal temperature difference in the tea garden would be sharp,over 10 ℃ on average and even up to 20 ℃ in maximum.Moreover,a clear night with little wind tends to lead occurrence of temperature inverse,thus triggering formation of frost.Temperature inverse is intense between 21:00 and 06:00,and peaks at dawn(05:00-06:00).The intensity of temperature inversion varies with height and reaches the most at 4 m above the ground.Tea plants on north slope are affected most by temperature inverse and susceptible to damage of frost.Ground temperature varies gently and peaks at dusk in a day,and moreover,is always higher on flat land than on north slope.