Drought and Flood Spatial and Temporal Variation in the Qinling Mountains
全球变化下秦岭南北旱涝时空变化格局

With global climate warming, the physical geographic transition zones in climate change has become quite significant. Based on monthly meteorological data from 59 stations in the Qinling Mountains from 1961-2010, we analyzed the spatial and temporal characteristics of drought and flood events using the Standardized Precipitation Index (SPI) and Empirical Orthogonal Function (EOF). We found that climate in the southern and northern Qinling Mountains presented a warming and drying trend over the last 50 years. Precipitation variation exhibited four periods: the normal period, humid period, dry period and transitional period. The EOF analysis showed that there were four typical precipitation spatial distribution patterns in the southern and northern Qinling Mountains: (1) the whole region identical drought or flood, separated by the Qinling Mountains, the distribution of precipitation increased from north to south in the Guanzhong Plain, while the south of Shaanxi presented a southwest to northeast zonal distribution; (2) the precipitation distribution in the northwest of the study area was contrary to that of the southeastern areas; (3) the precipitation distribution in the southwestern areas, in which Hanzhong Basin was the positive value center, was contrary to that of the northeastern areas; (4) the precipitation distribution in the eastern areas which Hanjiang Valley as the negative value center was contrary to that of the western areas. This study provides a theoretical basis for drought resistance, waterlogging prevention and disaster reduction in southern and northern sections of the Qinling Mountains.