On the Relationship Between Aerosol and Boundary Layer Height in Summer in China Under Different Thermodynamic Conditions

Abstract

The observed relationships between boundary layer height (BLH) and PM2.5 on a national scale remain unclear due to the dearth of observations. Here we investigated this relationship from a unique perspective of thermodynamic stability in the planetary boundary layer (PBL), using summertime (June–August) soundings from China for the period from 2014 to 2017. For all three times of soundings (0800, 1400, and 2000 Beijing time [BJT]), positive (negative) PM2.5 concentrations anomalies were found to correlate with negative (positive) BLHs anomalies relative to daily means. The negative correlation was strongest at 1400 BJT, followed by 2000 BJT and 0800 BJT. Overall, the PM2.5 was found to nonuniformly anticorrelate with BLH across China at 0800 and 2000 BJT. The strongest anticorrelation occurred in the North China Plain at 1400 BJT, in sharp contrast to the much weaker correlation in other regions characterized by much less polluted regions. The averaged PM2.5 in neutral boundary layers was higher than that in convective boundary layers (CBLs). The CBL, where the anticorrelation was the strongest, was conducive to dissipating more aerosol in the heavily polluted area in China than neutral boundary layer. The higher CBL formed under low cloud cover, low surface humidity, and strong wind speed was favorable for the dispersion of aerosol, in contrast to the stable boundary layers that happen under the highest cloud cover. Also, positive correlation was seen between stable boundary layer and PM2.5. The findings call for attention that the thermodynamical condition of PBL should be considered when examining the aerosol‐PBL interactions.

Aerosol-induced high precipitation events near the Himalayan foothills

“…This reduced radiation, in turn, reduces turbulence generation and hence the PBLH. The humidity values are found to be higher during the periods of higher AOD, which support the availability of more latent heat for the convection growth (Lou et al, 2019). For the present study, a negative BLH anomaly is found within and close to the domain, especially on the event day (see Figure 3).…”

Daily Global Solar Radiation in China Estimated From High‐Density Meteorological Observations: A Random Forest Model Framework

“…DGSR is also crucial for the utilization of solar energy through transformation of technologies (Wu et al, 2012(Wu et al, , 2016Tang et al, 2018;Prăvălie et al, 2019;Zou et al, 2019). In recent years, there has been an aggravation of air pollution in China induced by massive fossil fuel consumption and emissions coinciding with unfavorable weather conditions (Guo et al, 2016Lou et al, 2019;Yang, et al, 2018;Yang, Ye, et al, 2019;Zheng et al, 2019). On the one hand, this has significantly modulated the change in surface solar radiation (Che et al, 2005;Guo et al, 2018;Wang et al, 2012Wang et al, , 2013Wang & Wild, 2016;Zheng et al, 2018;He & Wang, 2020;Yang et al, 2020), while on the other hand, it has led to solar radiation becoming one of the fastest-growing and important sources of clean and renewable energy.…”

Distinct Impacts of Light and Heavy Precipitation on PM2.5 Mass Concentration in Beijing

“…On the other hand, the meteorology, including the planetary boundary layer (PBL), temperature, pressure, relative humidity, wind speed, wind direction, and precipitation, also exerts strong impacts on the PM 2.5 mass concentration (Chen et al, ; Garrett et al, ; Guo et al, ; He & Lin, ; He, Lin & Liu, ; Li, Feng, et al, ; Li, Guo, et al, ; Lou et al, ; Pearce et al, ). The variation of PBL height governs the concentrations of atmospheric pollutants near the surface since the aerosol particles generally concentrate within the PBL height (Garratt, ; Guo et al, ; Seidel et al, ).…”