基于标准降水指数的昌都地区夏季干旱时空特征分析

基于1980～2011年昌都地区7个气象站的逐月降水资料,采用标准化降水指数分析了昌都地区夏季干旱时空分布特征。结果表明,昌都地区夏季干旱的发生程度具有阶段性特征,20世纪80年代和90年代前期是较严重的干旱阶段,进入20世纪90年代轻旱和重旱的发生次数急剧减少,中旱的发生次数保持稳定。根据主成分分析,昌都地区夏季干旱在空间分布上具有较强的一致性同时也存在一定的区域性;根据因子分析将昌都地区分为北部、西部和南部3个区域,20世纪80年代至90年代前期北部干旱多于西部和南部,20世纪90年代后期至21世纪前期西部干旱增加,多于北部和南部。

Spatial and Temporal Summer Drought Characteristics in Changdu Based on Standardized Precipitation Index

Based on the monthly precipitation data of 7 weather stations in Changdu during 1980-2011,the temporal and spatial distribution characteristics of the summer drought was investigated using standardized precipitation index.The summer drought characteristics in Changdu shows large interannual variations,with more severe drought events occurred in 1980s and early 1990s.After the early 1990s,the frequency of light drought and severe drought events sharply decreased while the frequency of medium drought events kept stable.Using the principal component analysis method,the results showed that the characteristics of summer drought have discrepancy over different regions.In 1980s and early 1990s,the summer drought event in the northern of Changdu is more severe than that in the southern and western of Changdu.After the middle 1990s,the frequency of summer drought in the northern Changdu enhanced and was more frequent than that in the northern and southern of Changdu.