荒漠草原中间锦鸡儿冠层截留特征

以荒漠草原人工中间锦鸡儿（Caragana intermedia）为研究对象，利用2016-2017年监测获取的26次降雨事件，对比分析了两组灌丛（自然组和人工组）的冠层截留特征。结果表明：（1）试验期间共观测到有效降雨33次，总降雨量为251 mm，次平均降雨量和降雨强度分别为7.6 mm和1.14 mm/h，以雨量<2 mm，雨强<1 mm/h和降雨历时2-5 h的降雨出现次数最多；（2）自然组和人工组中间锦鸡儿平均截留量分别为1.11 mm和0.72 mm，平均截留率分别为24.81%和15.95%，两组灌丛截留存在极显著差异（P < 0.01）；（3）在雨量级>15 mm时，自然组（4.57%，CV=73.38%）和人工组（5.25%，CV=51.96%）平均截留率变异性相差最大；（4）自然组和人工组截留量与降雨量，降雨历时和降雨强度之间的关系可以用幂函数描述，截留率与三者的关系均用指数函数描述较好。在降雨特征相同的情况下，灌丛形态特征是影响中间锦鸡儿冠层截留的关键因素。

Characteristics of canopy interception by Caragana intermedia in desert grasslands

Canopy interception, an important component of water balance in arid and semiarid environments, plays a key role in re-vegetation and the hydrological cycle. Research regarding canopy rainfall interception across the sand-stabilizing shrub, Caragana intermedia, can aid in the elucidation of the eco-hydrological mechanism in desert grasslands. In this study, planted C. intermedia in a desert grassland was selected, and characteristics of canopy interception in two groups of shrubs (natural and planted) were compared and analyzed by monitoring 26 rainfall events from 2016 to 2017. The results showed that a total of 33 effective rainfall events were observed during the experiment, and the total and average amounts, and intensity of rainfall were 251 mm, 7.6 mm, and 1.14 mm/h, respectively. Overall, rainfall events of less than 2 mm and 1 mm/h, as well as a 2-5 h duration had the highest frequency. The average interception of C. intermedia in the natural and planted groups were 1.11 mm and 0.72 mm, respectively, and the average interception percentages were 24.81% and 15.95%, respectively. Significant differences (P < 0.01) in interception were detected between the two groups. When the rainfall amount was greater than 15 mm, the natural group (4.57%, CV=73.38%) and the planted group (5.25%, CV=51.96%) exhibited the greatest differences in average interception percentages. Small amounts of rainfall contributed to a higher percentage of interception. Furthermore, the interception amount of the natural and planted group exhibited a power function that tended to decrease with increasing rainfall amount, duration, and intensity, whereas the interception percentage for the two groups had an obvious exponential function in the relationship with the rainfall amount, duration, and intensity. The canopy interception of planted C. intermedia was significantly reduced, which was conducive to the improvement of the efficiency of precipitation utilization and is of great significance in the elucidation of the hydrological mechanism of decline of canopy interception by planted vegetation. Morphological characteristics of shrubs were the key factors affecting the canopy interception of C. intermedia under the same rainfall conditions. Based on the morphological structures of different shrubs, the canopy structure (height, crown projection area, leaf area) affected canopy interception progress of shrubs.