Shift in the Temporal Trend of Boundary Layer Height in China Using Long-Term (1979-2016) Radiosonde Data

The knowledge regarding how the boundary layer height (BLH) changes over time is still poor. Here we analyze the spatial and temporal changes in radiosonde-derived measurements of BLH over China from 1979 to 2016. A qualitatively robust and abrupt change of BLH occurred in 2004. Over the former period (from 1979 to 2003) a spatially uniform increase was found in the BLH, while over the latter period BLH decreased in a spatially nonuniform way. Second, the meteorological influence on the rising BLH was determined to have a negative association with soil moisture, lower tropospheric stability and relative humidity, and a positive association with the near-surface temperature. Yet, there was a different influence of meteorology on the BLH over the latter period, where a negative association was revealed with T-sfc and relative humidity. These findings shed new light on the long-term changes in air pollution across China.