甘肃省近58a春末夏初旱变化特征及其对夏粮的影响

Climatic Characteristics of Drought Events Occurred in Late Spring and Early Summer in Gansu Province and Its Influence on Agriculture in the Past 58 Years

利用甘肃省80个气象观测站1951～2008年的5～6月历年降水量分析了春末夏初干旱的变化特征,结果表明:河西走廊西部和陇东北部是春末夏初旱的高发区,河西走廊中东部、陇东大部、陇南东部是次高发区,陇中、甘南和陇南西部为低发区。全省春末夏初旱出现频率和干旱范围在上世纪60年代至80年代呈减少趋势,90年代至2008年为增加趋势。干旱站数占总站数的百分比与夏粮产量为显著负相关,与夏粮受旱灾面积、粮食减产量为显著正相关。春末夏初降水量与夏粮产量为显著正相关。

Based on precipitation data in late spring and early summer（May to June） during 1951-2008 from the 80 meteorological stations in Gansu Province,the drought events occurred in late spring and early summer in Gansu were analyzed.The results indicated that drought events occurred frequently in late spring and early summer in the west of Hexi Corridor and the north of east Gansu,and occurred secondarily in the eastern part of Hexi Corridor,most part of east Gansu and eastern part of south Gansu,and occurred less in middle Gansu,Gannan and western part of south Gansu.The frequency and range of drought events in late spring and early summer decreased from the 1960s to 1980s,and increased from the 1990s to 2008.The percentage of stations where occurred drought events in late spring and early summer to the total stations correlated negatively with the output of the summer grain crops,and rainfall in late spring and early summer correlated positively with the yield of summer grain crops.