Influence of Black Carbon Aerosol on the Atmospheric Instability

Abstract

To date, influence of aerosols on the atmospheric stability and hence on the convection/precipitation is not well understood. From the detailed analysis carried out using high‐accuracy radiosonde and Aethalometer measurements, a significant decrease in the convective available potential energy has been noticed in association with the increase in surface concentration of black carbon (BC) for a restricted range of precipitable water vapor and under similar environmental background (wind speed, direction, and cloud cover) over Gadanki (13.5°N, 79.2°E), a tropical rural site in southern peninsular India. A number of case studies along with statistical analysis indicate a notable perturbation in the temperature profile associated with high‐surface BC concentration conditions compared to the regional mean concentration of the same. A discernible fall in the temperature lapse rate within and above the local boundary layer in association with the higher BC concentration has been observed, which in turn reduces the available potential energy for convection decreasing the positive buoyancy required for a rising moist air parcel. This observation has been noticed over a nonurban location, but the phenomenon is not location dependent and is more applicable to the urban regions where BC concentration is likely to be much higher.

World War II Holds the Key to Understanding Global Warming and the Challenges Facing Science and Society

“…As previously noted [18], the long-duration series of radiosonde and aethalometer investigations undertaken by Talukdar et al [46] provide further support for the idea that tropospheric particulate heating reduces atmospheric convection. Their investigations showed that higher amounts of tropospheric black carbon (BC) aerosols can disturb the normal upward movement of moist air by heating the atmosphere, resulting in a decrease in the atmospheric convection parameters in association with the increase in the concentration of BC aerosols.…”

Mixing state of refractory black carbon in fog and haze at rural sites in winter on the North China Plain

“…Studies have focused on the chemical mechanisms such as condensation, coagulation, and heterogeneous oxidation for coating formation (He et al, 2015;Bond et al, 2013), while the connection between meteorological factors and coatings is relatively rare. Previous studies have shown that 95 wind speed and variation in the planetary boundary layer (PBL) can influence the concentration of BC (Talukdar et al, 2019) and that relative humidity (RH) affects the morphology and hygroscopic growth of rBC-containing particles (Laborde et al, 2013;Freney et al, 2010) .…”

“…These two-time points corresponded to the start of rBC decline and the lowest value of rBC respectively. This diurnal variation in rBC and wind speed can be explained by the diurnal variation in the boundary layer (Simpson and McGee, 2012;Talukdar et al, 2019 inversion conditions predominate in the boundary layer. The temperature rose, the wind speed increased to an average of over 2 m s -1 at midday, and the rBC declined rapidly with decreased atmospheric stability and increased turbulence.…”

Changing patterns in aerosol vertical distribution over South and East Asia

“…Note that the increasing trend in free tropospheric aerosol over India has important consequences on the background meteorology and dynamics besides their radiative forcing at those altitudes or below. Depending on the aerosol types, they can modify the cloud condensation nuclei (CCN) activity directly and the background instability 38 indirectly, thus affecting convection and/or precipitation processes. Chemical compositions at different altitudes need to be obtained and checked for any change in the trends.…”