Abstract: With the improvement of consumption level and an increase in low-carbon awareness, consumers have shown a clear preference for freshness, environmental friendliness and high goodwill of fresh products. To this end, the supplier makes preservation and emission reduction efforts to improve the freshness and environmental friendliness of fresh products, while the retailer promotes fresh products based on freshness, carbon labels and other green labels to improve their goodwill. Cooperation between the supplier and retailer can promote positive interactions between consumers and environmentally friendly brands, thereby leading to low-carbon consumption. The input of preservation, emission reduction and publicity in the cold chain are all intertemporal, and an increase in preservation input in the cold chain will improve the freshness of fresh products and thus promote the growth of goodwill, but it will also lead to an increase in carbon emissions, which will have a negative impact on goodwill. So, studying the dynamic equilibrium strategy and coordination mechanism of low-carbon operation of cold chain is of great significance for the preservation optimization, emission reduction, publicity input decision-making and sustainable development of the cold chain.
Considering the comprehensive impact of freshness preference, low-carbon preference and goodwill preference for fresh products, a differential game model of a two-echelon cold chain is constructed taking the freshness level, emission reduction and goodwill as state variables. Firstly, considering the intertemporal of freshness-keeping, emission reduction and publicity investment and the interaction between the state variables in cold chain, the optimal equilibrium strategy, optimal trajectory of state variables and optimal profit of cold chain members under decentralized and centralized decision-making are compared and analyzed. Secondly, the coordination performances of unilateral and bilateral cost sharing contracts on the economic and environmental benefits of the cold chain are compared. Finally, based on the Taguchi robust parameter design method, the key factors affecting the economic and environmental benefits are explored.
Some valuable conclusions are obtained. The freshness trajectory of fresh products is monotonous, the emission reduction trajectory changes direction at most once, and the goodwill trajectory is volatile. The improvement of freshness preference helps improve the economic benefits of the cold chain, but it is not beneficial to the environmental benefits. Consumers’ low carbon, goodwill preferences and abatement cost coefficient have a greater impact on the economic and environmental benefits. Furthermore, the bilateral cost sharing contract that satisfies certain conditions can improve the economic and environmental benefits of the cold chain system at the same time, and the improvement effect will be more obvious when the consumer’s goodwill preference is higher or the emission reduction cost coefficient is lower. Finally, the dynamic equilibrium strategy of the cold chain members in different decision models and the cost sharing ratio in the cost sharing contract are independent of time, which indicates the controllability of the cold chain members’ decision making and the applicability of the coordination mechanism in the long-term low-carbon operation of the cold chain.
To sum up, this paper explores the dynamic equilibrium strategy and effective coordination mechanism of the long-term low-carbon operation of the cold chain system, and provides theoretical guidance for long-term preservation and emission reduction decisions of the supplier and long-term publicity decision of the retailer. The supplier in a dominant position should actively guide the retailer to sign a bilateral cost-sharing contract, share the cost of cold chain preservation, emission reduction and publicity, and improve the economic and environmental benefits of the cold chain.
This paper assumes that the supplier and retailer are the main participants, and future research will consider the government as a game party to study the impacts of carbon cap-and-trade, government subsidies and other policies on the systematic decision-making and benefits in the long-term low-carbon operation of the cold chain, while taking the maximization of social welfare as the optimization objective. In addition, this paper considers the marginal profits of the supplier and retailer as constants, and in the future, the price factor can be considered as a decision variable to further analyze the dynamic equilibrium decision-making and coordination optimization of the cold chain.

Key words: multiple preferences, joint emission reduction, preservation efforts, differential game

摘要： 低碳经济背景下,冷链中保鲜投入的增加会提高生鲜品新鲜度水平从而提高品牌商誉,但同时也会导致冷链碳排放增加从而对商誉产生负影响。针对这一特性,将冷链中新鲜度水平、减排量和商誉作为状态变量,考虑消费者新鲜度、低碳和商誉偏好对生鲜品需求的综合影响及状态变量间的交互作用,构建微分博弈模型,研究了不同决策模式下低碳冷链的长期最优均衡策略、状态变量最优轨迹及系统效益,设计并比较了不同契约机制对该冷链系统的协调绩效。通过算例对模型的有效性进行了验证,并结合Taguchi方法进行了鲁棒性和敏感性分析。研究发现,当多重偏好共同影响生鲜品需求时,该冷链系统中新鲜度轨迹具有单调性,减排量轨迹最多改变一次方向,而商誉轨迹随时间变化呈现多变性;消费者低碳和商誉偏好对冷链系统经济和环境效益的影响更大;改进的双向成本分担契约可同时提高冷链系统的经济和环境效益,且消费者商誉偏好越高或减排成本越低时改善效果越明显。

关键词: 多重偏好, 联合减排, 保鲜努力, 微分博弈