Long-term (2010-2024) lidar observations of cirrus clouds at Wuhan (30.5°N, 114.4°E), China

Cirrus clouds play a crucial role in the Earth’s climate by regulating its radiative balance. Their optical and radiative properties exhibit significant variability, influenced by both spatial and temporal distribution. This study investigates the geometrical and optical properties of cirrus clouds using 15 years (2010–2024) of 532-nm ground-based polarization lidar observations at Wuhan (30.5°N, 114.4°E), a mid-latitude site over central China. A cloud detection algorithm and optical parameter inversion procedure were developed to identify overall 2033 cirrus cases. The geometrical and optical characteristics of these clouds were analyzed in detail. Cirrus clouds have cloud top and base heights of 12.4±2.1 km and 9.7±2.6 km, respectively, with thickness of 2.7±1.6 km and cloud top temperature of -50.2 ± 9.0 °C. Cloud top height reaches its maximum in summer (13.8 km) and minimum in winter (9.6 km). The cloud optical depth is variable, mainly ranging from 0 to 1 with an average of 0.34±0.35, suggesting that cirrus clouds are predominantly optically thin to moderately thick. The lidar ratio is 28.58±12.57 sr, while the volume and particle depolarization ratios are 0.32±0.08 and 0.40±0.11, respectively. These findings generally reflect the typical characteristics of cirrus clouds in the Asian mid-latitude region.