Measurement report: Ice nucleating abilities of biomass burning, African dust, and sea spray aerosol particles over the Yucatan Peninsula

Abstract

Abstract. Most precipitation from deep clouds over the continents and in the intertropical convergence zone is strongly influenced by the presence of ice crystals, whose formation requires the presence of ice nucleating particles (INP). Although there are a large number of INP sources, the ice nucleating abilities of aerosol particles emitted from oceans, deserts, and wildfires are poorly described at tropical latitudes. To fill this gap in knowledge, the UNAM-MicroOrifice Uniform Deposit Impactor-Droplet Freezing Technique (UNAM-MOUDI-DFT) was built. Aerosol samples were collected in Sisal and Merida, Yucatan (Mexico) under the influence of cold fronts, biomass burning (BB), and African dust (AD), during five short-term field campaigns between January 2017 and July 2018. The three different aerosol types were distinguished by characterizing their physicochemical properties. Marine aerosol (MA), BB, and AD air masses were found to contain INP; the highest concentrations were found for AD (from 0.071 L−1 to 36.07 L−1), followed by MA (from 0.068 L−1 to 18.90 L−1), and BB (from 0.063 L−1 to 10.21 L−1). However, MA had the highest surface active site density (ns) between −15 °C and −30 °C. Additionally, supermicron particles contributed more than 72 % of the total INP concentration independent of aerosol type; MA had the largest contribution from supermicron particles.

African dust particles over the western Caribbean – Part I: Impact on air quality over the Yucatán Peninsula

“…Cerón et al (2002) reported large concentrations of Na, Cl, and Mg that originated from sea salt, when analyzing the composition of rainwater from the Yucatán Peninsula. The high levels of S can be associated with local anthropogenic activities such as vehicular, ship, and industrial emissions (e.g., Corbett and Fischbeck, 1997;Cerón-Bretón et al, 2018). Additionally, given the short distance between Mérida and the GoM, it is possible that dimethylsulfide (DMS) production from plankton in the GoM could be a natural source of S, as has been shown in other studies (e.g., Rosinski et al, 1988;Kloster et al, 2006;Vallina and Simó, 2007).…”

“…If the foreign biological particles are opportunistic pathogens, they can cause a variety of diseases in the receptor regions, such as the Yucatán Peninsula. Finally, these particles can impact the development of precipitation and affect the regional hydrological cycle when they serve as efficient ice-nucleating particles (e.g., Rosinski et al, 1988;Córdoba et al, 2020).…”