Abstract：
In this study, to understand the seasonal dynamics of air-sea exchange and its regulation mechanisms, we investigated polycyclic aromatic hydrocarbons (PAHs) at the air-sea interface in the western Taiwan Strait in combination with measurements and machine learning (ML) predictions. For 3-ring PAHs and most of 4- to 6-ring, volatilization and deposition fluxes were observed, respectively. Seasonal variations in air-sea exchange flux suggest the influence of monsoon transitions. Results of interpretable ML approach (XGBoost) indicated that volatilization of 3-ring PAHs was significantly controlled by dissolved PAH concentrations (contributed 24.0 %), and the gaseous deposition of 4- to 6-ring PAHs was related to more contaminated air masses originating from North China during the northeast monsoon. Henry\'s law constant emerged as a secondary factor, influencing the intensity of air-sea exchange, particularly for low molecular weight PAHs. Among environmental parameters, notably high wind speed emerges as the primary factor and biological pump\'s depletion of PAHs in surface seawater amplifies the gaseous deposition process. The distinct dynamics of exchanges at the air-water interface for PAHs in the western TWS can be attributed to variations in primary emission intensities, biological activity, and the inconsistent pathways of long-range atmospheric transport, particularly within the context of the monsoon transition.
摘要：
在这项研究中,了解海气交换的季节动态及其调节机制，我们结合测量和机器学习（ML）预测研究了台湾海峡西部海气界面的多环芳烃（PAHs）。对于3环PAHs和大多数4到6环，观察到挥发和沉积通量，分别。海气交换通量的季节性变化表明了季风过渡的影响。可解释ML方法（XGBoost）的结果表明，3环PAHs的挥发受到溶解的PAH浓度（贡献24.0％）的显着控制，4至6环PAHs的气态沉积与东北季风期间来自华北的更多污染空气团有关。亨利定律常数作为次要因素出现，影响海气交换的强度，特别是对于低分子量的多环芳烃。在环境参数中，显著高风速作为主要因素出现，生物泵在表层海水中多环芳烃的消耗放大了气态沉积过程。西部TWS中PAHs的空气-水界面交换的独特动态可归因于初级排放强度的变化，生物活性,以及远距离大气传输的不一致路径，特别是在季风过渡的背景下。
