3）SWAT-ASW模型具有滨河湿地和隔离湿地的水文循环过程，能够很好的反映长江源流域夏汛期(7.15-9.30)径流的过程。SWAT-ASW模型比SWAT模型和SWAT-HEW模型在夏汛期径流的模拟结果更好(NSE = 0.65和R2=0.64)。此外，该模型能够从模型机理角度很好的解释高寒沼泽湿地在长江源流域的涵养水源和调节洪峰功能。
|其他摘要||Alpine swamp wetland (ASW) decreased dramatically in Headwater region of Yangtze River (HYR) during the last 30 years due to the climate change. Functions of maintaining water resources and adjusting runoff balance were hold by ASW. Runoff process in summer rainfall season could be changed as the decrease of ASW. It helps us to understand the relationship between climate and hydrology in HYR by detecting how ASW affect runoff process. Therefore, the effect of ASW on runoff process in summer rainfall season was studied by a developed SWAT-ASW model. The main findings were below:
1)28% of ASW areas were decreased in last 30 years (1975-2004) in HYR. The ASW declined more in the period of 1990-2004 than that in period of 1975-1990. Net Primary Production (NPP) shortened faster in the decreasing areas of ASW than that in non-decreasing areas of ASW. The ecosystem stability of non-decreasing areas of ASW was better than that of decreasing areas of ASW under same precipitation density. Surface water volumes were hold by wetland depths. Surface water volumes were 13.58×108m3 ，12.44×108m3 and 9.75×108m3 in the years of 1975,1990 and 2004, which was about 1.06%，0.91% and 0.73% of total runoff volumes.
2) Result of SWAT model runoff simulation at ZMD was “satisfied” (NSE=0.63 and R2=0.58). While it was “satisfied” in TTH (NSE=0.51 and R2=0.57). Therefore, SWAT model was satisfied about runoff simulation in HYR. In addition, runoff process was underestimated in spring rainfall season by SWAT.
3) The riparian swamp wetland water cycle and geographic isolated swamp wetland water cycle were both introduced to SWAT-ASW model in this study. The new SWAT-ASW modeled the runoff process much better than SWAT and SWAT-HEW in rainfall season (7.15-9.30) (NSE = 0.65, R2=0.64). The mechanism of runoff process during rainfall season was explained clearly by SWAT-ASW in HYR.
4) The runoff was shortened in summer rainfall season as the ASW decrease. When ASW decrease 10% and decrease 30%, runoff decreased 6.8% and 10.7%. The more ASW decrease, the more runoff decrease. The same situation was in surface runoff and lateral runoff. When ASW decrease 10% and decrease 30%, surface runoff decreased 16.4% and 29.7%, lateral flow decreased 9.6% and 14.9%. However, to groundwater and ET, the more ASW decrease with the more increase of them. When ASW decrease 10% and decrease 30%, groundwater increased 7.6% and 14.1%, ET increased 1.6%和3.2%. In addition, bare big flood happened more and middle flood decreased under the ASW decrease from period 1975-1990 to period 1990-2004. Rainfall-runoff coefficient in ZMD decreased, while it increased in TTH under the ASW decrease. The summer flood events frequencies were both increased in ZMD and TTH, flood duration and rising time were both shortened by ASW decrease.|
李佳. 高寒沼泽湿地退化对长江源流域夏汛期径流的影响[D]. 北京. 中国科学院大学,2015.