This article introduces a MATLAB-based radiometric model as a crucial initial step in evaluating the feasibility Differential Absorption Lidar (DIAL) systems for remote sensing of minor gaseous atmospheric constituents such as methane, a potent greenhouse gas. This model offers flexibility in parameter customization, considering factors like target gas, wavelength range, and atmospheric conditions, enabling to optimize system parameters, assess performance, and gain insights into improving measurement accuracy. We validate the model and find it capable of retrieving lidar signals for methane sensing concentrations of $2.085$ ppm over 800-meter distances using an OPO lidar system at around $3 \ \mathrm{\mu m}$. We explore two DIAL approaches, range-resolved and IPDA, each suited for specific scenarios. Furthermore, we highlight that this simulation framework extends beyond methane, from $\mathrm{CO_2}$ to alcohol vapors. This article serves as a valuable resource for researchers and practitioners in atmospheric science and remote sensing, offering insights into DIAL system feasibility and optimization.