Surface Meteorological Conditions and Boundary Layer Height Variations During an Air Pollution Episode in Nanjing, China

Abstract

The evolution of planetary boundary layer (PBL) was investigated using observations from a laser ceilometer, an eddy covariance system, and an automatic meteorological station in the north of Nanjing city during an air pollution episode in 2016–2017 winter. Based on 7‐day observation under clean to polluted day, we recorded the temporal variations of backscatter signals observed by the ceilometer, and then intercompared the planetary boundary layer height (PBLH) retrieved from individual methods. The results show that backscatter signal gradient, standard deviation, and wavelet transform analysis methods generated similar PBLH values and PBL diurnal variation patterns. Moreover, the PBL structure varied diurnally, with distinct patterns corresponding to clean and polluted days. Based on these measurements, the relationships between PBLH, weather conditions, and contaminants were analyzed. Results show that on clean days, strong surface turbulence exchange makes the PBL fully developed and makes the PBLH increase sharply after sunrise, with a maximum of 1,483 m; on polluted days, stable synoptic conditions and the weaker wind speeds facilitated the accumulation of air pollutants, leading to smaller net surface radiation and weaker turbulence. Consequently, these conditions during polluted days led to lower PBLH values, which were typically less than 900 m.

PBL Height From AIRS, GPS RO, and MERRA‐2 Products in NASA GES DISC and Their 10‐Year Seasonal Mean Intercomparison

“…Surface forcing response, drag, turbulence, and vertical mixing are strongly evident here and play a critical role within PBL compared to their importance in the overlying “free atmosphere” (Stull, 1988). The PBLH is a vital parameter in climate models, weather forecasts, and air quality prediction (Allabakash & Lim, 2020; Yin et al., 2019). PBLH data are available from the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC), which provides data processing, archiving, and distribution services for many Earth science products.…”

A study of the effect of aerosols on surface ozone through meteorology feedbacks over China

“…Using the WRF-CMAQ model, Nguyen et al (2019) also found that the ADE could reduce the annual average PBLH in East Asia by -46.47 m (−8.13%). The lower boundary layer caused by aerosols is usually also accompanied by calm winds and higher relative humidity values (Yin et al, 2019). Here, the 10-m wind is found to be slower by -1% to -7.5% (Fig.…”

Diurnal climatology of correlations between the planetary boundary layer height and surface meteorological factors over the contiguous United States

“…Previous studies have shown that the climatology of the PBLH has significant geographical and seasonal variances ( Seidel et al, 2012;Guo et al, 2016;Zhang et al, 2020a), which is important in research related to climate and air pollution (van der Kamp and McKendry, 2010;Yin et al, 2019). To investigate the spatial variations of the key diurnal features of the PBLH over the CONUS and to facilitate comparisons between our work and previous studies, Figure 2 shows the spatial patterns of the mean PBLH at 0000 UTC and the mean diurnal maximum PBLH in different seasons during the time period 2007-2016.…”