近48年大同市旱涝灾害对气候变化的响应

根据1960~2007年大同逐月平均气温和逐月降水资料,分析了近48 a大同市在全球增暖影响下气温和降水的变化;采用滑动t检验法和信噪比法分析了气温突变的时间点;在此基础上研究了大同市气温突变前后旱涝灾害的变化,并运用马尔可夫模型对未来5 a旱涝状况进行了预测。结果表明:近48 a来大同市气温呈明显的上升趋势;随着气温的升高,该市干旱灾害的比例增幅比较明显,特别是在气温突变后,干旱(4级和5级)的概率达到63.64%,2009~2012年处于"偏旱"的概率较大。     

Effects of climate change and human activity on lake shrinkage in Gonghe Basin of northeastern Tibetan Plateau during the past 60 years

Changes in the status of freshwater resources are a topic of major global,regional and local concern.This is especially so in the arid and semi-arid regions of China,where shortage of water resources plays a crucial role in limiting sustainable socioeconomic development,as well as in sustaining natural ecosystems.Recent climate change,as well as the effects of localized human activity,such as the use of water for irrigation agriculture,may have significant effects on the status of the water resources in the region.Here,we report the results of a study of changes in the areas of lakes in Gonghe Basin,northeastern Tibetan Plateau of China,over the last 60 years.The data were acquired from optical satellite images and demonstrate that the total water area of lakes in Gonghe Basin decreased significantly from the 1950 s to 1980 s.The cause is ascribed mainly to human activity including exploitation of farmland,against a background of increasing population;in addition,climatic data for the region demonstrate a minor drying trend during this period as the temperature increased slightly.After the construction of several reservoirs,significant amounts of water were redistributed to promote irrigation agriculture and we conclude that this caused a significant shrinkage of the natural lakes.However,both the area of farmland and the population size remained approximately constant after 1990.We conclude that the variation of the total area of lakes during the second period was mainly controlled by climatic factors(precipitation and temperature).As the regional temperature reached a new high,the area of some of the lakes decreased sharply before finally maintaining a relatively steady state.We emphasize that anthropogenic climate change and human activity have both significantly influenced the status of water resources in the arid and semi-arid regions of China.     

北疆棉区棉花生长期气候变化特征及其对棉花发育的影响

利用1961～2007年北疆棉区代表站气温、降水、日照时数资料,采用气候趋势系数等方法,分析了北疆柿区棉花生长季的气候变化特征,结果显示,北疆棉区棉花生长季呈现平均气温升高、降水增多、日照时数减少,初霜推迟、终霜提早、无霜期延长,10℃初日提早、终日推迟、持续天数延长、积温增加等特征.对比分析1991年以来的棉花发育期资料,棉花自播种至裂铃的各发育期均表现为提前的趋势,停止生长期略有推后,棉花全生育期天数增加.气候变化对北疆棉区棉花生产的影响以有利为主.