Dataset associated with "Volcanic ash ice nucleation activity is variably reduced by aging in water and sulfuric acid: the effects of leaching, dissolution, and precipitation"

Volcanic ash nucleates ice when immersed in supercooled water, giving it the potential to influence weather and climate from local to global scales. However, the ice nucleation activity (INA) of ash can be modified by interaction with various chemical species during atmospheric transport. In the experimental study associated with this dataset, we show that the INA of two mineralogically distinct ash samples from Fuego and Astroni volcanoes is variably reduced when immersed in water or aqueous sulfuric acid for minutes to days. Aging in water decreases the INA of both ash samples by up to two orders of magnitude, possibly due to a reduction in surface crystallinity and cation availability accompanying leaching. Aging in sulfuric acid leads to minimal loss of INA for Fuego ash, which is proposed to reflect a quasi-equilibrium between leaching that removes ice-active sites and dissolution that reveals or creates new ones on the pyroxene phases present. Conversely, exposure to sulfuric acid reduces the INA of Astroni ash by one to two orders of magnitude, potentially due to selective dissolution of ice-active sites associated with surface microtextures on some K-feldspar phases. Analysis of dissolved element concentrations in the aged ash leachates indicates supersaturation of select mineral species which might have precipitated and so also contributed to altering the INA of the ash. These results highlight the key role that leaching, dissolution, and precipitation likely play in the aqueous aging of volcanic ash with respect to its INA