荔枝林小气候特征及其与大气候的关系

利用2002—2003年间荔枝林小气候梯度观测资料，分析荔枝林小气候特征及其与背景大气候之间的关系。受“山谷风”下沉气流影响，荔枝林冠层气温与背景大气候相比，夜间气温明显偏低，其日变化幅度偏高，年平均偏低0．35—0．75℃，冬春季和夜间更加明显。因此在冬季冷空气过程中，荔枝林将承受较长的低温时间。不同梯度气温相比，冠层气温比冠层上偏高0．2—0．4℃，夏秋季和白天更加明显。荔枝林具有显著而稳定的增湿效应，全年月平均相对湿度均高于背景大气候7％左右。荔枝林气温、相对湿度等小气候因素与背景大气候相比，具有相同的时间变化趋势，并存在显著的线性关系。此研究结果可为应用常规气象站监测、预测气象资料推算荔枝林小气候状况，开展农用天气服务和防灾减灾工作提供依据和参考。

Microclimatic Characteristics in Litchi Forest in Relation to Macroclimate

Using microclimatic dada recorded from 2002 to 2003 in litchi (Litchi chinensis) forest in Huadu, the relationship between the microclimate and macroclimate was studied. The results indicated that average monthly air temperature in litchi forest canopy was lower by 0.35-0.75 than that obtained at meteorological station in Huadu. This was particularly obvious in winter and spring, and at night. Temperature in the canopy was by 0.2-0.4 higher than that above the canopy, which was more obvious in summer and autumn and in the daytime.Average monthly relative humidity in litchi forest increased by 7% compared to that in macroclimate, indicating that the humidification in litchi forest always causes diseases and pests.