基于金沙江下游梯级水电开发区10个气象站1956-2011年的逐月降水资料，运用线性倾向估计法、Morlet 小波分析法和 R/ S 分析法对多年降水和季节降水变化及其趋势、周期和持续性特征进行分析。结果表明：研究区1956-2011年降水量呈波动式下降趋势，降水倾向率为-1.338 mm/ a；季节降水中除春季呈微小上升趋势外，夏、秋和冬季均呈下降趋势，且空间差异明显；夏、秋季的降水量占全年的81.1%，尤以夏季为主导，占57.4%；年降水存在1～2 a、4 a 、8 a 、14 a和31 a 的周期变化规律，其中8 a 的周期尤为明显，通过90%置信水平检验；研究区降水序列总体上存在明显的 Hurst 现象，具有持续性特征，未来降水仍会维持减少趋势。
[Objective] This study was to provide theoretical basis for getting sustainable development of rural energy in Tibet into reality.[Method] By reviewing the rural energy resources in Tibet,we analyzed the characteristics and potential of rural biomass utilization in Tibet,and further put forward the sustainable countermeasures on the firewood substitution in Tibet.[Results] Renewable energies including hydraulic,geothermal,solar and wind resources are abundant in Tibet,while there is just a few of fossil energy resources such as oil and coal,with uneven distribution and poor exploration conditions.Traditional consumption of biomass energy resource accounts for a large proportion of the total energy consumption in Tibetan rural districts,which causes potential damage to the fragile ecological environment on the Tibetan Plateau.The excessive use of biomass energy destroyed the vegetation and evoked the environment deterioration such as the intensification of the water and soil loss and the declining of the soil fertility.[Conclusion] It is essential for Tibet to change its rural energy consumption structure,implement the Tibetan firewood alternative energy strategy and try to make full use of renewable energy such as solar energy,wind energy,hydro-energy instead of native vegetation and animal＇s droppings in order to reduce the adverse impacts of the irrational energy consumption on the ecological environment in Tibet.
