云南石林典型植被类型的降水垂直分配及水平汇聚规律观测研究

变化环境下的水资源管理及植被恢复是岩溶区亟待解决的现实问题。以云南石林岩溶区典型植被类型为对象,设置实验样地并开展了2018-2019年两个雨季的野外观测,分别对不同植被类型的降雨分配及汇聚规律进行了探索。结果表明:石林地区受到亚洲季风的控制,降水量的年内变化具有显著的季风区特征,即高度集中于湿季,特别是5-8月,降雨类型以小雨和中雨占主导,两者在全年降水场次中的比例分别为70%、15%;各实验观测植被类型的穿透雨量、树干径流量以及截留量均随着林外降雨量的增加而增大,降雨量的分配特征为降雨量>穿透雨量>截留量>树干径流量;各植被类型的径流系数差别明显,变化范围为0.01%~0.36%,石漠化裸地区径流系数最大而坡耕地最小,但整体来看都非常小;产流的降雨量阈值差别较大,其范围为2.0~6.4 mm,随着林外降雨量的增多,各观测样地的地表产流量也呈现增大的态势。本观测研究结果可以为岩溶区水资源管理与生态环境恢复保育提供科学依据。

Vertical distribution and horizontal convergence of precipitation in typical vegetation types of Shilin County, Yunnan Province

The management of water resources and vegetation restoration under the changing environment is a practical problem needing urgent attention in karst areas. Taking the typical vegetation types in the karst area of Shilin County, Yunnan Province as the research object, experimental plots were set up and field observations were carried out in the two rainy seasons of 2018-2019. The rainfall distribution and convergence laws of different vegetation types were explored respectively. The results show that Shilin area was controlled by the Asian monsoon, and the annual variation of precipitation presented significant monsoon characteristics. The precipitation mainly concentrated in the rainy season, especially from May to August, dominated by light rain and moderate rain, with the proportion of 70% and 15% respectively in the annual precipitation events. The throughfall of canopy layer, stem flow and interception of different vegetation types all increased with the increase of the rainfall outside of the forest, and the distribution of rainfall was outside rainfall > throughfall > interception > stem flow. The runoff coefficients of different vegetation types varied greatly, the range of variation was 0.01%-0.36%, with that of rocky desertification bare area being the largest and that of slope farmland being the smallest, but on the whole, the values are all meagre. The threshold range of runoff was 2.0-6.4 mm, with the increase of outside rainfall, the surface runoff of all plots also showed an increasing trend. The results can provide scientific basis for the management of water resources as well as the restoration and conservation of ecological environment in karst areas.