【摘要】 胡杨作为干旱区的主要建群种,对维持生态环境稳定有重要意义。然而在全球变化背景下,胡杨分布区的干旱状况变化尚不明确。本研究采用Mann-Kenda11检验等方法,分析了近50年全球胡杨分布区帕尔默干旱指数(PDSI)的时空变化特征。结果表明:(1)1960-2012年,全球胡杨分布区平均PDSI呈显著(P<0.01)上升趋势,速率为0.259/10a。其中,秋季平均PDSI增加速率最大,为0.26/10a,而冬季呈下降趋势(-0.18/10a)。(2)PDSI指数存在明显的空间差异。在40°E~50°E,2.5°S~37.5°N区域,PDSI呈下降趋势,表明该区气候在往干旱方向发展。其中,伊朗南部等地区(或国家)PDSI减小速率最低,为0.38/10a,而肯尼亚东部减少速率最大,为0.696/10a。(3)而在35°E~37.5°E,35°N~37.5°N和65°E~105°E,22.5°N~47.5°N范围内,PDSI呈上升趋势,说明气候变得相对湿润。其中新疆部分PDSI增长速率最快,为0.444/10a(P<0.01)。其次为摩洛哥,叙利亚,伊拉克,土耳其等国家,平均PDSI增长速率为0.325/10a,但趋势并不显著。而河西走廊、内蒙古等地区和巴基斯坦、哈萨克斯坦等国家PDSI增长速率较低,分别为0.193/10a和0.166/10a。更多还原

【Abstract】 As a constructive species in arid area,Populus has important significance for maintaining the ecological environment. Under the background of global change,however,the drought variation in distribution area of Populus euphratica is not clear. This study used statistical methods such as Mann-Kenda11 trend test to analyze the characteristics of temporal and spatial changes in the Palmer Drought Index(PDSI) in global distribution area of Populus euphratica during 1960-2012. The results show that:(1) In 1960-2012,the average PDSI had a significantly(P < 0. 01) increasing trend with a rate of 0. 259 per decade. Among them,the increasing rate of autumn average PDSI was the largest with the rate of 0. 26 per decade while the winter PDSI showed a downward trend with the rate was-0. 18 per decade.(2) Simultaneously,there were obvious differences in the space PDSI index. During 40 °E ~ 50 ° E,2. 5 ° S ~ 37. 5 ° N,PDSI was on the decline,indicating the climate in this area tended to be dry. The decreasing rate of PDSI in Iran South and other regions(or countries) was minimum with a rate of 0. 38 per decade(P < 0. 01). However,the decreasing rate of PDSI in Kenya Eastern was the largest and was 0. 696 per decade(P < 0. 01).(3) During 35 °E ~ 37. 5 °E,35 ° N ~ 37. 5 ° N and 65 ° E~ 105 ° E,22. 5 ° N ~ 47. 5 ° N,PDSI showed a rising trend,which illustrates that the climate had become relatively humid. Xinjiang was the area with the fastest growth rate of PDSI,which was 0. 444 per decade(P <0. 01). Followed by Morocco,Syria,Iraq,Turkey and other countries,where the average PDSI growth rate was0. 325 per decade,but the trend was not significant. In Hexi corridor,Inner Mongolia and other regions and countries such as Pakistan,Kazakhstan,PDSI growth rate was low,which was 0. 193 per decade and 0. 166 per decade.更多还原