【摘要】 南海北部陆坡边缘海底分布有浅表层水合物，这类水合物埋藏浅、覆盖层薄，对海底温压变化敏感，易发生分解。本文针对南海北部内孤立波、内潮及季节性底层水体温度变化，应用一维热传导模型，模拟其对浅表层水合物分解的影响，并开展参数敏感性分析。研究表明：单次内孤立波引起的温压扰动不足以引发海底以下约0.078 m的水合物赋存区（Hydrate Occurrence Zone,HOZ）顶部分解，而内潮引起1.72℃的温升持续18 h，在60 d内将热量传入至HOZ顶部，可导致约4 cm水合物分解。季节性底水升温幅度为1.76℃，持续5个月，在1 a内推动分解界面持续下移，累计分解厚度可达14 cm，影响效果明显，表明持续升温效应显著强于瞬时扰动。同时，参数敏感性分析表明，温度幅值与有效热扩散系数共同控制热扰动传输深度与分解速率。水合物初始分布特征亦显著影响分解过程，其中，地温梯度、甲烷通量和渗透率决定HOZ顶底部位置，而孔隙度调节初始饱和度及分解敏感性。本研究为评价预测浅表层水合物稳定性及甲烷释放风险等提供了重要依据。更多还原

【Abstract】 Shallow-buried gas hydrates are distributed along the continental slope margin of the northern South China Sea. These hydrates are characterized by shallow burial depths and thin overburden layers, rendering them sensitive to changes in seabed temperature and pressure and prone to dissociation. Focusing on internal solitary waves, internal tides, and seasonal bottom-water temperature variations in the northern South China Sea, this study employs a one-dimensional heat conduction model to simulate their effects on shallow subsurface hydrate dissociation and conducts a parameter sensitivity analysis. Results indicate that temperature-pressure perturbations induced by a single internal solitary wave propagate less than a few centimeters into the sediments, falling short of reaching the top of the Hydrate Occurrence Zone(HOZ) located approximately 0.078 m below the seabed, and are thus unlikely to trigger dissociation. In contrast, an internal-tide-induced temperature increase of 1.72℃ lasting 18 hours transfers heat to the HOZ top within 60 d, potentially leading to the dissociation of approximately 4 cm of hydrate. Seasonal bottom-water warming with an amplitude of 1.76℃ persisting for five months drives the dissociation front downward continuously over one year, resulting in a cumulative dissociation thickness of up to 14 cm.This significant impact demonstrates that the effect of sustained warming is substantially stronger than that of transient perturbations. Furthermore, parameter sensitivity analysis reveals that temperature amplitude and effective thermal diffusivity jointly control the propagation depth of thermal perturbations and the dissociation rate. The initial distribution characteristics of hydrates also significantly influence the dissociation process; specifically, the geothermal gradient, methane flux, and permeability determine the positions of the HOZ upper and lower boundaries, whereas porosity regulates the initial saturation and dissociation sensitivity. This study provides a critical basis for evaluating and predicting the stability of shallow subsurface hydrates and the associated risks of methane release.更多还原