Spatiotemporal variability of near-surface air temperature lapse rates in the Qinghai-Tibet plateau using high-density meteorological observations.

The near-surface air temperature lapse rate is a crucial indicator that reflects atmospheric stability and is an important parameter for extrapolating regional surface temperatures. However, due to the scarcity of temperature monitoring stations and the complex topography of the Qinghai-Tibet Plateau, the true distribution of near-surface air temperatures in the region remains unclear. In this study, we analyzed the spatiotemporal patterns of near-surface air temperature lapse rates on the Qinghai-Tibet Plateau using high-density meteorological stations and gridded data. The results showed that the average temperature lapse rate for the plateau in 2015 was 5.89 ± 2.42 °C/km, with significant seasonal heterogeneity. The lapse rate was highest in spring (6.38 ± 2.65 °C/km), followed by summer (5.95 ± 2.24 °C/km) and winter (5.80 ± 3.41 °C/km), with the lowest value observed in autumn (5.44 ± 2.82 °C/km). These rates exhibited a spatial pattern of being higher in the southeast and lower in the northwest, decreasing with increasing altitude. In autumn, the temperature lapse rate was primarily influenced by elevation. Additionally, the near-surface temperature lapse rate was lower during the day and higher at night, reaching its peak at 6.15 ± 2.88 °C/km at midnight and its lowest point at 5.42 ± 2.13 °C/km at noon. The results of this study were independently validated at the Qomolangma and Nam Co stations, showing good agreement with observations, which supports the applicability of the findings across the entire Qinghai-Tibet Plateau.