早春逆温条件下茶园近地温度时空分布特征

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

为防止早春晚霜对茶叶的危害,首先要探明逆温条件下茶园近地气温和地温的时空分布特征。对平地、北坡和南坡等不同地形上茶树冠层温度水平分布、地温日变化以及近地7 m高度范围内气温垂直分布规律的研究结果表明,初春晴朗天气条件下,茶园昼夜温差很大,均在10℃以上,最高达20℃,且晴朗少风条件下夜晚容易出现逆温现象,从而形成霜冻。21:00—06:00时段内逆温程度较强,05:00—06:00达到最强。逆温效应随高度变化,且在4 m高处达到最大;北坡受逆温影响最大,极易遭受霜害。地温变化平缓,傍晚达到一天中的最大值,且平地始终高于北坡。

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 fiat 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 fiat land than on north slope.