Orbital integrated path differential absorption lidar at 1.84 µm for detecting water sources on Mars

We propose an orbital differential absorption lidar operating near 1.84 µm to observe water vapor on Mars. With optimized wavelengths, the system offers high sensitivity to low-altitude water vapor and enables high-resolution, day-and-night observations of potential source regions-helping to close the existing observational gap in the lower atmosphere. Global simulations using feasible lidar parameters and the Mars climate database indicate that differential absorption optical depth can be measured with relative random errors below 1%, using a 1 mJ, 2 kHz laser, a 0.3 m telescope, and 1 km horizontal averaging. The water vapor weighted column mixing ratio can be retrieved to within 1% accuracy using climatological data, except in the southern polar region, where errors can reach 4% during northern winter.