中文摘要：

为研究气候变化对东北三省地表干湿状况的影响，利用该区1960-2005年72个气象站的观测资料，采用Penman-Monteith模型计算了各站的潜在蒸散量，由潜在蒸散量和降水量之比构建干燥度指数，并采用Kriging法进行空间插值以分析其区域特征。结果表明，该区地表干湿状况具有明显的时空变化特征。1960-1979年间，由于降水减少和潜在蒸散增加，地表干燥度指数呈增加趋势，水汽压差增大是潜在蒸散增加的主要原因；1980-2005年间，大部分地区地表干旱状况有所减缓，其中以黑龙江省和吉林东部尤为明显。降水增加和潜在蒸散减少是地表干旱状况趋缓的主要原因，风速降低和净辐射减小导致潜在蒸散减少。总体而言，气候变化并未加剧东北三省的干旱化。

英文摘要：

To investigate the impact of climate change on surface dry-wet status in northeast China, aridity index in three provinces of Helongjiang, Jilin and Liaoning was calculated from 1960 to 2005 on the basis of meteorological datasets in 72 stations. The aridity index was defined as a ratio of potential-evapotranspiration to precipitation. Potential-evapotranspiration was computed by using Penman-Monteith model. Upscaling was completed by Kriging interpolation to address the spatial characters of aridity index. Results indicated that there was a variation in the dry-wet status with significant spatiotemporal characteristics in this region. Higher values of the aridity index occurred in the period from 1960 to 1979 and increased generally. The increase in the aridity index was attributed to a reduction in precipitation and an increase in potential-evapotranspiration that was induced by an augment in vapor pressure difference. By contrast, the surface in most of this region, particularly in Heilongjiang Province and the east part of Jilin Province, tended to be wetting during the period from 1980 to 2005 due to an increase in precipitation and a reduction in potential-evapotranspiration. The reduction in potential-evapotranspiration can be explained by a decline of wind speed and net radiation. As a whole, climate change did not aggravate surface aridity in three provinces of northeast China over the last several decades.