A General Circulation Model (GCM) is a climate model that mathematically simulates the planetary atmosphere or ocean's circulation. GCMs are essential for weather forecasting, climate understanding, and predicting climate change. They help study fronts, which are transition zones between different air masses. An air mass is a large body of air with consistent temperature and humidity properties in a horizontal direction. GCMs can also depict trapping mechanisms, such as the convergence of mid-density water over intertidal mudflats with denser water in the main channel, creating distinct fronts.