考虑植被蒸腾水分来源结构的岩溶小流域时变增益水文模型模拟研究

Karst hydrological modeling is the hot topic in the Hydrology research field. Vegetation is one of the most important factors impact on the karst hydrological processes through the transpiration. In the small karst watershed, because of the binary hydrological structure, the vegetation transpiration also exhibits binary structure. The vegetation transpiration water is simultaneously from the soil water and the epikarst water. However, we slightly considered the binary structure of the vegetation transpiration in the hydrological simulation. This research will combine the stable hydrogen and oxygen isotope technique and the karst DTVGM hydrological modeling to carry out the following three researches. Firstly, we will study the water uses sources structure of vegetation transpiration in the small karst watershed. Then the DTVGM hydrological model will be established considering the vegetation transpiration structure impacts and will be applied in a typical small karst watershed. Besides, the hydrological effects of vegetation will be studied based on the DTVGM modeling. The research will be helpful for the rocky desertification management, rational vegetation restoration and water resources management in the karst watershed.

岩溶水文循环模拟研究是国际国内关注的热点问题。植被是岩溶水循环的重要参与者，植被通过蒸腾作用影响着岩溶水文循环过程。由于岩溶区小流域具有特殊的二元水文结构，植被蒸腾耗水水分来源也表现为二元结构，具体表现在植被蒸腾耗水来源于土壤层和表层岩溶带两个含水层中。然而，现阶段岩溶水文模拟研究对植被蒸腾耗水的二元结构的影响考虑尚有不足。本研究针对该方面研究的不足，以典型岩溶小流域为例，利用稳定氢氧同位素技术结合非线性时变增益水文模型模拟方法，进行以下三个方面研究：（1）研究以岩溶小流域为单元的植被蒸腾耗水水分来源结构特征；（2）构建考虑植被蒸腾耗水结构影响的岩溶小流域非线性时变增益水文模型；（3）模拟不同植被恢复情景下，考虑植被蒸腾耗水结构影响的植被水文效应。本研究为岩溶小流域石漠化治理、合理植被恢复和水资源管理提供科学依据。

岩溶水文循环模拟研究是国际国内关注的热点问题。植被是岩溶水循环的重要参与者，植被通过蒸腾作用影响着岩溶水文循环过程。本研究以断陷盆地典型岩溶小流域为例，选择泸西湾半孔小流域为对象，利用稳定氢氧同位素技术结合非线性水文模型模拟方法，研究植被蒸腾耗水对岩溶小流域的影响机制，研究结论如下：（1）泸西湾半孔流域降水有42和18年的主周期，降水呈现每年减少2.05mm的下降趋势。降水突变年份在1985年。（2）石漠化区低强度降雨（30mm/h）条件下，下渗水主要来源于土壤水。中度（60mm/h）和强度（90mm/h）降雨条件下，下渗水主要来源于裂隙水。（3）湾半孔小流域乔木林地增加了流域总面积的39.63%，石漠化得到有效治理，石漠化面积减少了58.80%。（4）湾半孔小流域植物蒸发效应主要在土壤表层, 泉水同位素几无蒸发效应影响。(5)构建了湾半孔小流域岩溶泉径流模拟模型，纳什效率系数达0.85，干旱期岩溶泉来源于裂隙流，可占93%以上，湿润期来源于裂隙流和土壤水。模拟结果表明，植被蒸散发来源于裂隙流，将降低植被蒸腾作用，而来源于土壤水分将增加植被的蒸腾作用。