Freezing efficiency of feldspars is affected by their history of previous freeze–thaw events
| Autor: | Elzbieta Pach, Albert Verdaguer |
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| Přispěvatelé: | Ministerio de Ciencia, Innovación y Universidades (España) |
| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| ISSN: | 1463-9084 1463-9076 |
| Popis: | Among the different aerosol mineral particles that contribute to induce ice nucleation (IN) in the troposphere, feldspars have been identified as the most active. Nevertheless, which surface properties make some feldspars more efficient than others, i.e. able to induce IN at higher temperatures, is still unclear. In addition to that, surface properties of such materials can change as they are exposed to a variety of environmental conditions while traveling through the troposphere. Here, freezing temperature of water droplets deposited on feldspar minerals has been measured as a function of consecutive freeze-thaw cycles. We found an increase of the freezing temperature for the initial cycles followed by approximately constant freezing temperature for consecutive cycles. We call this a "history effect". This effect is more evident for samples aged in standard room conditions and it disappears if the sample is exposed to oxygen plasma. Oxygen plasma generates OH groups at the surface, facilitating IN and cleans the surface from organic contamination, unblocking pores at the surface, believed to be the most active IN sites on feldspars. A similar process is suggested to happen during the history effect, when consecutive freeze-thaw events unblock IN sites. The authors thank C. Marcolli for discussion on results and their interpretation. This work has been supported by the Spanish Government under the project PID2019-110907GB-I00 and the ‘‘Severo Ochoa’’ Program for Centres of Excellence in R&D (CEX2019-000917-S). E. Pach acknowledges the Spanish Ministry of Science and Technology for the Juan de la Cierva Formation grant. With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S). |
| Databáze: | OpenAIRE |
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