## 1 Introduction
The \"Port Emissions Toolkit\", unveiled in 2018, advocates for the integration of port incentives aimed at low-emission vessels into strategic frameworks, a proposition that merits acknowledgment within the International Maritime Organization's greenhouse gas mitigation strategy of the same year. Scholarly discourse posits that the cornerstone for targeted carbon dioxide reduction initiatives in ports hinges upon the formulation of a comprehensive carbon dioxide emission inventory [5; 6; 7]. Ports are required to initially quantify their carbon dioxide emissions. Thereafter, it is imperative to ascertain strategies for the mitigation of port-related emissions in an economically efficient manner. The strategic collaboration between the International Maritime Organization's (IMO) GloMEEP energy efficiency project and the International Association of Ports and Harbors (IAPH) is facilitating the development of port emission inventories in select nations. The \"Port Emissions Inventory Guide\" published by the United States Environmental Protection Agency (EPA) in 2020, stipulates the necessity for precise data monitoring across a spectrum of vessels, cargo handling equipment, and terrestrial machinery within port confines, thereby demanding an expanded and refined scope for carbon dioxide emission monitoring objectives. Owing to the multiplicity and intricacy of port operations, the surveillance of carbon dioxide emissions at ports entails the aggregation and synthesis of diverse datasets. The deployment of an array of technologies and instruments is indispensable for this surveillance, posing challenges in demarcating the surveillance boundaries and ensuring precision [8]. Adherence to a plethora of international, national, and local legislative and regulatory frameworks is mandatory for the monitoring of carbon dioxide emissions at ports. The accurate delineation of carbon dioxide emission issues at ports presents a pressing challenge that warrants immediate resolution. As of now, only Shandong Port in China has publicly released the \"2020 Port Mobile Source Air Pollutants and Greenhouse Gas Emission Inventory\" in 2022, which has propelled the assessment of China's port system and the development of pollution reduction and carbon dioxide emission mitigation policies. Carbon dioxide emissions within ports encompass both direct and indirect emissions; the consumption of diesel and gasoline represents direct sources of carbon dioxide emissions, while purchased electricity and steam are indirect sources. The primary greenhouse gas in question is carbon dioxide [9]. Indirect carbon dioxide emissions are calculated through supply chain emission accounting by enterprises and government agencies within the port, using the carbon dioxide Emission Flow (CEF) tracking method [5], and can be more accurately determined based on input-output models and other analytical approaches [10]. However, there are currently issues with the precision of direct carbon dioxide emission measurements and the scope of monitoring, including the phenomenon of unaccounted emissions from certain sources. Against the backdrop of the aforementioned real carbon dioxide reduction imperatives and the policies proposed by the international community to safeguard the path of common human development, the demand for carbon dioxide emission inventories has increased. The need for more precise carbon dioxide emission monitoring data and a broader range of surveillance has accelerated research in the field of carbon dioxide emission monitoring. Currently, the estimation of carbon dioxide emissions at ports primarily involves the quantification, statistical calculation, and monitoring of emissions from the port and its associated enterprises [11]. Emissions within the port are mainly attributed to vessels docked at the port, land vehicles within the port area, terminal equipment, and cargo handling machinery.