PDF《祁连山排露沟流域降雪消融与融水径流分析》

the snowfall in the shady slope is 8.36% more than in sunny slope. (3) The amount of snow ablation was at the range of 0.184 ~ 0.526 mm/d, and snow ablation of arbor forest accounted for 78.72% of bush forest, for 37.66% of shady slope grassland, for 32.61% of sunny slope grassland;

snow ablation of shrub forests accounted for 47.45% of shady slope grassland, for 41.09% of sunny slope grassland;

the snow ablation of shady slope grassland accounted for 34.98% of sunny slope, that is to say that the snow time of shady slope grassland was more 63.12% than the time of sunny slope. (4) The basin monthly runoff depth was 0.28 ~ 23.19 mm, the annual runoff depth was 83.45 mm. Melt- water runoff formation of snow ablation depth was 4.60 mm, accounting for 5.51% of the total annual runoff. The ?ndings have great signi?cances for future development of the runoff yield mechanisms, for revealing the function of water conservation and its producing mechanism, for assessing the function of water conservation in Qilian mountains and providing basic data and references of arti?cial enhancement rain and snow research projects. Key words: snow;

snow ablation;

meltwater runoff;

Pailugou watershed of Qilian Mountains

97 第33 卷中南林业科技大学学报关于山地森林生态系统涵养降水过程和机理的 研究中,人们更加注重流域产流能力及其对依赖径 流而生息繁衍的人居生态系统的稳定与发展.西北 内陆山区径流形成受到多种因素的影响,其中冬、 春季甚至初夏季节降水以降雪的形式存在,降雪消 融又直接影响着径流的补给过程和年内变化,而降 雪消融与降雨在影响径流过程和机理方面有所不同, 对降雪消融过程和融雪径流开展分析研究,有助于 更加科学认识和掌握森林生态系统涵养水源的过程 和机理.因此,降雪消融过程如何影响径流的问题 已是众多学者研究的热点.有些学者研究了积雪与 融雪径流水化学特征 [1] ,大多数学者基于遥感研究 积雪分布或积雪变化或积雪消融与径流的关系 [2-7] . 但是通过长期定位监测的方法研究降雪、积雪消融 与径流关系的相关研究还较少.祁连山冰雪融水是 河西走廊的生命之源,其变化直接影响河西走廊的 经济社会发展.因此,利用祁连山森林生态站长期 固定试验流域多年监测数据,通过研究不同植被对 降雪、积雪消融影响及其径流对其响应研究,对于 揭示水源涵养功能机理及其流域产流机制具有重要 意义,并为将来开展祁连山水源涵养功能评估和人 工增雨雪项目提供基础数据和参考.

1 研究区概况 祁连山(36°30′ ~ 39°30′N, 93°30′ ~ 103°E) 是我国西北地区著名的高大山系之一,属典型大 陆性气候特征.一般山前低山属荒漠气候,年均 温6℃左右,年降水量约

150 mm.中山下部属半 干旱草原气候,年均温

2 ~ 5℃,年降水量

250 ~

300 mm.中山上部为半湿润森林草原气候,年均 温0~1℃,年降水量

400 ~

500 mm.高山属寒 冷湿润气候,年均温

3 ~ 5℃左右,年降水量约

800 mm.祁连山东部气候较湿润,西部较干燥. 试验区位于祁连山西水林区排露沟流域(38°24′N,100°17′E), 流域面积274 hm2 , 呈 中卵形,土壤平均厚度 0.5m.森林总面积 118.3 hm2 ,覆盖率 43.16%,郁闭度 0.7 左右,流域内阴 坡以乔木林为主,阳坡以草地为主,海拔

3 200 m 以上的亚高山以灌木林为主.

2 研究方法 2.1 降雪消融样地监测法 2.1.1 样地布设 根据立地类型,在祁连山排露沟流域乔木林 内外、灌丛林内外、阴阳坡和不同坡位分别布设 对照监测样地,共布设