Relationship between Drought and Precipitation Heterogeneity: An Analysis across Rain-Fed Agricultural Regions in Eastern Gansu, China

Based on daily meteorological data from 55 stations in eastern Gansu 1960 to 2017, the characteristics of drought process and precipitation heterogeneity were analyzed, relationship between was evaluated. Results showed that there 1–3 processes study area every year. Drought north-central regions more frequent than those other regions. Droughts mainly manifested as intra-seasonal droughts, especially across spring summer. PCD (Precipitation Concentration Degree, concentration degree at a certain time) ranged 0.2 0.7 area. increased autumn but decreased summer winter for most 2017. PCP Period, shortest time which concentrated in) late April early May spring, mid-to-late July summer, mid-September autumn, January winter. In last 58 years, has remained consistent regions, varying by approximately 10 days. addition insignificant changes winter, days with light moderate rain presented declining trend, autumn. The larger PCD, fewer rain, stronger intensity. However, east-central region, weaker This difference is related evapotranspiration. Additionally, later PCP, intensity, particularly When ≥0.5 ≥0.4 after August respectively. appeared 28–56% periods when seasonal above normal. middle September, droughts 7% Our results show although less leading influencing factor dry rain-fed agricultural areas, influence should be also considered prediction diagnosis drought.