新疆塔里木河流域洪水发生率非平稳性特征及气候变化影响研究

新疆洪水灾害近年来有加剧趋势,但其特征与机理尚未有深入探讨。论文利用核估计和Bootstrap方法深入分析新疆塔里木河(塔河)流域洪水发生率的非平稳性及不确定性,同时采用广义可加模型(GAMLSS)构建洪水发生频率与协变量(大气环流因子、降水和气温指标等)的关系并定量辨识主要影响因子。研究表明:1)塔河流域洪水在1960年代左右和1990年代左右两个时期高频发生,两个洪水高发期之间洪水发生次数多为2或3次,且与极端降水发生次数较为吻合;2)洪水发生率呈现显著非平稳性,从1990年左右洪水发生次数持续上升,并达到峰值,表明洪水发生频率及强度呈加剧趋势;3)冬季AMO和AO是影响新疆塔河流域洪水发生的重要因子,而冬季NAO和SOI则是影响塔河流域5个州的洪水发生次数最为显著的大气环流指标。论文研究可为新疆塔河流域洪灾预测与预警及流域洪水管理提供关键理论依据。

Nonstationarity of Flooding Processes in the Tarim River Basin and Climate-related Impacts

Aggravation of flood has been observed in Xinjiang, China. However, no reports are available addressing changing properties and related mechanisms. In this paper, flooding frequency in the Tarim River Basin, the largest inland arid river basin in China, was analyzed by using the Kernel smoothing technique and bootstrap resampling method. Besides, the flood frequency and extreme precipitation events were analyzed by using the POT method. Both stationary and non-stationary models were conducted by using GAMLSS (Generalized Addi-tive Models for Location, Scale and Shape) to model the flood frequency and its relations with explanatory variables (e.g. time, climate index, precipitation and temperature). The results indicated that: 1) The flood occurrence in the Tarim River Basin clustered in two periods, i.e. ~1960s and ~1990s with around 2-3 fluctuations. 2) The change of flood frequency is nonstationary process. Persistent increase of flood frequency can be observed since 1990s and the flood frequency gradually reached its peak value, implying evident aggravation of floods in terms of magnitude and frequency. 3) Winter AMO and AO are the principle influencing factors of the change of flood frequency, while winter NAO and SOI are two critical climate indices influencing flood frequency in the Tarim River Basin. The results of this study can provide great scientific and theoretical support for the management of floods and mitigation of flood hazards.