The vertical variability of black carbon observed in the atmospheric boundary layer during DACCIWA

Abstract

<jats:p>Abstract. This study underlines the important role of the transported black carbon (BC) mass concentration in the West African monsoon (WAM) area. BC was measured with a micro-aethalometer integrated in the payload bay of the unmanned research aircraft ALADINA (Application of Light-weight Aircraft for Detecting IN situ Aerosol). As part of the DACCIWA (Dynamics–Aerosol–Chemistry–Cloud Interactions in West Africa) project, 53 measurement flights were carried out at Savè, Benin, on 2–16 July 2016. A high variability of BC (1.79 to 2.42±0.31 µg m−3) was calculated along 155 vertical profiles that were performed below cloud base in the atmospheric boundary layer (ABL). In contrast to initial expectations of primary emissions, the vertical distribution of BC was mainly influenced by the stratification of the ABL during the WAM season. The article focuses on an event (14 and 15 July 2016) which showed distinct layers of BC in the lowermost 900 m above ground level (a.g.l.). Low concentrations of NOx and CO were sampled at the Savè supersite near the aircraft measurements and suggested a marginal impact of local sources during the case study. The lack of primary BC emissions was verified by a comparison of the measured BC with the model COSMO-ART (Consortium for Small-scale Modelling–Aerosols and Reactive Trace gases) that was applied for the field campaign period. The modelled vertical profiles of BC led to the assumption that the measured BC was already altered, as the size was mainly dominated by the accumulation mode. Further, calculated vertical transects of wind speed and BC presume that the observed BC layer was transported from the south with maritime inflow but was mixed vertically after the onset of a nocturnal low-level jet at the measurement site. This report contributes to the scope of DACCIWA by linking airborne BC data with ground observations and a model, and it illustrates the importance of a more profound understanding of the interaction between BC and the ABL in the WAM region. </jats:p>

An Exploratory Investigation of UAS Regulations in Europe and the Impact on Effective Use and Economic Potential

“…As an illustrative example, the procedure required to acquire the flight permission for a particular system, which has been operated since 2013, is provided. The UAS "ALAD-INA" [4], with a weight of 24.9 kg and a wingspan of 3.6 m, operated by the Institute of Flight Guidance of TU Braunschweig, is applied for atmospheric research, thus for altitudes up to 1000 m. The UAS has been operated on during different years in Germany [5][6][7], in Benin [8,9] and in Svalbard [10,11].…”

A meteorological dataset of the West African monsoon during the 2016 DACCIWA campaign

“…Altstädter et al . 45 could show that the observed black carbon layer measured at the Savè super site was transported from the south with maritime inflow and was mixed vertically downwards when the nocturnal LLJ has formed. Performing high-resolution chemistry-transport modelling in combination with the surface and radiosonde data, Deroubaix et al .…”

Wind Shear of Low-Level Jets and Their Influence on Manned and Unmanned Fixed-Wing Aircraft during Landing Approach

“…As an example of an unmanned aerial system, ALADINA is used in the following [32]. It has a weight of almost 25 kg and a wind span of 3.6 m and has been applied for atmospheric research up to an altitude of 1000 m at different locations in Germany [32][33][34][35], Benin [36], and Svalbard [37]. ALADINA is operated up to a constant wind speed of 15 m s −1 ; however, further parameters also have to be taken into account.…”