平凉黄土山地带气候变化、人类活动与水资源问题

Climate change,human activity and water resources issues in loess hilly areas in Pingliang

依据1951—2014年气象数据统计分析及野外调研资料,讨论了1951年以来陇东黄土山地带降水量、气温变化特征及趋势。结果表明,伴随全球气候变暖,平凉地区最近20年以来不论全年、冬半年或夏半年平均气温都呈明显上升趋势,自1997年以来平均气温比之前40年上升1.2℃。相比之下,除冬半年降雪量略呈减少趋势外,年总降水量并不存在显著增加或减少趋势,而更倾向于存在7 a左右长周期变化或2 a左右短周期波动。伴随气温逐年上升而降水量并不增加,退耕还林等人工干预措施不断加剧的总趋势,土壤水分或浅层黄土地下水资源量不断减少,进而影响林木生长、农业生产和生态环境有效恢复。指出黄土高原沟壑-丘陵地带退耕还林工程实施过程中,根据地形地貌特征科学合理规划耕地、休耕地、林地、草地以及树(草)种选择、林木密度等是今后长期需要研究的课题。

Based on data from meteorological records during 1951 to 2014 and field observations,this paper statistically analyzed the variation of precipitation and temperature over past 60 years and prospected their discernible overall trends. With the global warming,the average temperature in annual,summer and winter half year has been going up in the recent 20 years. The average temperature has been risen of 1. 2℃ since 1997,compared to 40 years ago. In contrast,besides the amount of precipitation in winter half year has the trend of decrease,the amount of annual total precipitation is inclined to show about 7-year of long periodic and 2-year of short periodic oscillations rather than a linear trend. Under the temperature rising while precipitation stable,and intensive of human activities,in particular,the development of large-scale of returning farmland to forests program,the soil moisture and groundwater will possibly continue decreasing. Finally,human living and ecological recovery will be affected by scarce of water resources in the hilly areas of the Loess Plateau. Thus,it is a long and key project to scientifically plan the farmland,fallow farmland,forest,grassland and trees（ grass） species selection,forest density,etc. according to topography and geomorphology during the returning farmland to forests program in gully and hilly region in loess plateau.