In order to realize the water-energy-food cooperation in the Beijing-Tianjin-Hebei region, 31 indicators were selected to construct a safety index system for water-energy-food coupling system from reliability, synergy and resilience. The security level of water-energy-food coupling system in the Beijing-Tianjin-Hebei region from 2000 to 2020 was analyzed, and the joint risk probability was calculated based on Copula function. The results show that the security index of water-energy-food coupling system in the Beijing-Tianjin-Hebei region shows an overall upward trend from 2000 to 2020. The annual average index of Beijing is the highest, reaching 0.63, and that of Hebei is the lowest, only 0.48. There is no significant difference in reliability levels among different regions, and they all exhibit poor levels. The main obstacles influencing the security of the water-energy-food coupling system include per capita water resources, per capita energy consumption, the proportion of groundwater supply, and carbon dioxide emissions. The probability of achieving a relatively safe level of reliability, synergy, and resilience in the Beijing Tianjin Hebei region is 0.723, and uneven development will affect the overall security of the water-energy-food coupling system.

With the standardized precipitation evapotranspiration index (SPEI) used as the drought reflection index, the Mann-Kendall (M-K) trend test was used to analyze the drought change of the Haihe River Basin, the empirical orthogonal function analysis method was used to analyze main modes of drought distribution, and cross wavelet transform and Pearson correlation analysis were adopted to study the correlations between sunspots, large-scale circulation factors, and drought in the Haihe River Basin on monthly, seasonal, and annual scales, respectively. The results show that from 1960 to 2017, the Haihe River Basin developed to aridity, with SPEI decreasing 0.16 per decade on annual scale, 0.015 per decade on seasonal scale, and 0.004 per decade on monthly scale, respectively; the first mode of drought distribution of the Haihe River Basin was the global uniform distribution pattern, and the second mode was the south-north inverse distribution pattern, reflecting the influence of latitude on the drought distribution; among the atmospheric circulation factors, Niño3.4 has a high correlation with drought in the Haihe River Basin (with negative correlation on the annual and seasonal scales and positive correlation on monthly scale), and sunspots have a significantly negative correlation with drought in the Haihe River Basin and also have a profound impact on the occurrence of drought events in the Haihe River Basin.