Synergistic Patterns of Urban Economic Efficiency and the Economic Resilience of the Harbin–Changchun Urban Agglomeration in China

Regional economic efficiency and resilience are necessary conditions for sustainable regional economic development, and urban agglomerations are the core carriers of regional economic development. Exploring the synergistic patterns between economic efficiency and economic resilience is crucial to the sustainable economic growth and development of urban agglomerations and their surrounding regions. To measure the economic efficiency, economic resilience, and synergistic capacity of the Harbin–Changchun urban agglomeration from 2010 to 2019, the super-efficient SBM model, the entropy-TOPSIS model, and the Haken model are used. The economic efficiency of the Harbin–Changchun urban agglomeration shows a mild upward trend between 2010 and 2019, while its economic resilience shows a more stable upward trend. A distinct phased pattern of synergies exists between economic efficiency and economic resilience. In terms of the time trend, a “down-up-down” pattern emerges, while in terms of the spatial pattern, a dumbbell-shaped structure appears with “highs at the north and south and lows in the middle.” Combined synergy values are highest in the north and south of Qiqihar, Jilin, Siping, Liaoyuan, and Mudanjiang, followed by Harbin and Changchun; the values are lowest in the middle of Suihua, Daqing, and Songyuan. This study also proposes strategies to weaken inter-regional differentiation and to increase economic efficiency and economic resilience across cities in accordance with the actual situation.