High-repetition-rate ozone differential absorption lidar for low-altitude tropospheric ozone observations.

Traditional ozone differential absorption lidar (DIAL) systems are commonly operated in a low-repetition-rate, high-pulse-energy regime to secure sufficient signal-to-noise ratio (SNR) for long-range measurements. For low-altitude tropospheric profiling, however, the shorter propagation path and weaker attenuation make it possible to achieve the required SNR through pulse accumulation rather than high single-pulse energy. Here, we present RD150, a high-repetition-rate ozone DIAL system for profiling ozone in the 0.15-3 km range. Based on an all-solid-state Raman ultraviolet laser, the system emits the 280 and 295 nm DIAL wavelength pair at 5 kHz with ultraviolet pulse energies at the ten-microjoule level. Comparisons with ozonesonde profiles show that RD150 reproduces low-altitude ozone structures well. A near-surface horizontal comparison with a ground-based ozone analyzer further demonstrates that the system can reliably track low-altitude ozone variability. One year of continuous observations confirms stable long-term operation and the ability to resolve seasonal and vertical structural variability. Taken together, these results indicate that, for short-path low-altitude ozone DIAL, kilohertz-level pulse accumulation with µJ-level ultraviolet pulses can provide a practical alternative to continued reliance on higher single-pulse energy, thereby enabling a compact ozone lidar implementation based on a chiller-free air-cooled transmitter and whole-instrument gimbal-mounted scanning capability.