【摘要】 应用涡度相关技术,对云南5种主要森林生态系统的水汽通量连续多年观测,利用2003—2015年观测数据探讨了不同森林生态系统的蒸散特征和变化规律,并分析了蒸散量与土壤含水量和降水量的关系.结果表明:(1)不同森林蒸散的日变化均表现为单峰曲线,但蒸散启动和结束时间以及峰值出现的时间有所差异;(2)不同森林蒸散量的年变化表现为单峰曲线,最大值在7月,最小值在1月,雨季蒸散大于干季蒸散;(3)多年平均年蒸散量为热带雨林795.68 mm、橡胶林774.54 mm、稀树灌草丛435.35 mm、亚热带常绿阔叶林767.69 mm和亚高山针叶林438.83 mm,分别占各生态系统年降水量的55.05%、59.77%、56.58%、52.80%和42.17%,显示云南主要森林生态系统均为水分盈余状态;(4)不同森林的蒸散量与土壤含水量的关系不尽相同,说明不同森林生态系统对水分的利用策略存在不同.研究结果可为评价森林生态系统的生态水文效应和水分利用策略及理解其对气候变化的响应提供科学基础.更多还原

【Abstract】 Evapotranspiration in five major forest ecosystems in Yunnan was measured using eddy covariance from 2003 to 2015. The characteristic and variation of evapotranspiration were compared, and the relationship between evapotranspiration and soil water content as well as precipitation was analyzed in the present study. The results showed that the dynamic patterns of diurnal evapotranspiration of five forest ecosystems were all characterized by a single-peak curve, but the occurrence of peaking time and the patterns in diurnal evapotranspiration were not consistent. Both daily and monthly evapotranspiration among five forest ecosystems followed an unimodal curve form. Maximum evapotranspiration rate was observed during July and minimum during January. Likewise, the seasonal evapotranspiration was characterized by the highest evapotranspiration during rainy season and lowest during the dry season. The multi-year mean annual evapotranspiration(the percentage of evapotranspiration to precipitation) of the tropical rainforest, rubber plantation, savanna, subtropical evergreen broad-leaved forest, and subalpine coniferous forest was 795.68 mm(55.05%), 774.54 mm(59.77%),435.35 mm(56.58%), 767.69 mm(52.80%), and 438.83 mm(42.17%), respectively. It implied that the moisture of those forest ecosystems is sufficient. The relationship between evapotranspiration and soil water content was not the same over different forest ecosystems, which showed that the water-use strategies were varied among different forest ecosystems. The results provided a scientific basis for the assessment of ecological hydrological effects and water-use strategies of forest ecosystems, and the understanding of the responses to climate changes.更多还原