1.5m贴地气层内最低温度考察和贴地层逆温特征分析

Investigations on Minimum Temperature and Analysis of Characteristics of Temperature Inversion in Air Layer 0～1.5m near Ground

福建省年度极端最低气温绝大多数是由平流降温后的晴夜辐射降温(A型低温)引起的,使果树遭受重或严重冻害的低温都出现在A型中。据坡顶、坡中、坡下的1.5m贴地气层内最低温度考察资料分析,晴天A型低温在1.5m贴地气层内也存在贴地层逆温。贴地层逆温强度随相对坡位增大而增大;随排汇比的减小而减小。应用贴地层逆温特征,在果树的嫁接中采用高位嫁接,用耐冻力强的树种作砧,让其处于温度最低的气层中,可减轻或避免低温给果树造成的冻害。而处于空气易进难出的坡底冷湖中的贴地层逆温现象不明显,即使采用高位嫁接,其减轻冻害的作用不大。

Annual extreme minimum temperature in Fujian Province mostly resulted from dropping in temperature （A Model Dropping） arisen from terrestrial radiation in fine nights after dropping in temperature arisen from advection. The serious or most serious freezing damage of fruit tree appeared in A Model Dropping. At the top, bottom and middle of slope in two locations, the investigation on the minimum temperature in air layer 0 - 1.5m near ground showed that the temperature inversion also appeared in air layer 0 - 1.5m near ground, when A Model Dropping happened. Intensity of temperature inversion in air layer developed, when relatively sloping location rose and reduced by ratio of release to influx reduced. Applying character of temperature inversion and using freeze endured variety as rootstock in air layer of the minimum temperature in grafting would evade or reduce freezing damage arisen from the minimum temperature. But the phenomena of temperature inversion in air layer 0 - 1.5m near ground in the bottom of the slope （cold lake） where the cold air went into easily and out difficultly, was not obvious. There was no significant effect in reducing freezing damage even by grafting.