Abstract:The North China Plain is one of the most severely drought affected areas in China, with global warming intensifying aridification in this alluvial plain. Drought may be attributed to multiple factors, among which precipitation and temperature are the most important. It is widely recognized that the Standardized Precipitation Evapotranspiration Index (SPEI) is advantageous for both spatial-and temporal-scale characteristic assessments; thus, it is a better index for evaluating the evolution of drought in the North China Plain due to climate change than other drought indices, such as the Palmer Drought Severity Index (PDSI), Standardized Precipitation Index (SPI), and Z index. In this study, monthly mean precipitation and temperature data from 45 meteorological stations in the North China Plain were used to calculate the SPEI index and investigate the spatial and temporal characteristics of drought in the North China Plain from 1961 to 2010. The analysis produced the following results. First, during the last 5 decades, a significant increase in temperature and a slight decrease in precipitation occurred in the North China Plain, resulting in a general aridification trend throughout the region. The drought time series in the North China Plain may be characterized from the analysis based on the SPEI index, and was consistent with existing publications.Second, a noticeable warming tendency with a mean warming rate that exceeds the national average level occurred in North China. Diverse aridification tendencies characterized the North China Plain because of variable warming rates. An analysis of typical stations showed that the more noticeable the warming, the deeper the intensity of aridification. Third, the drought feature may be well formulated using the ratio of weather stations with different drought intensities. Empirical orthogonal function (EOF) analysis was conducted based on a 12-month-scale SPEI index of the 45 meteorological stations from 1962 to 2010, and the top three eigenvectors were selected to explore the spatial and temporal distribution of drought occurrence in the North China Plain according to their spatial and temporal coefficients. The first mode shows consistency in the entire region, and it is the most important spatial distribution indicator of drought in the North China Plain. High values emerged in the middle of the region, including the western part of Shandong and the northern and southern parts of Henan, demonstrating that these areas are more sensitive to drought. There was no clear tendency in the time coefficient of the first mode. The second mode shows contrasts between the southern and northern parts of the North China Plain, which are consistent with the distribution of warming rate. The time coefficients show that drought in the northern part of the plain has been aggravated, whereas drought in the southern part has been alleviated, which may be due to differences in the warming rates throughout the research region. Warming rates in the northern part of the North China Plain are higher, so the aridification tendency is far more severe than that in the southern part of the North China Plain. The third mode contrasts the tendency between the eastern and western parts of the North China Plain, showing no significant tendency in the time coefficient.