Influence of the ambient humidity on the concentration of natural deposition ice nuclei

MARIA LAURA LOPEZ; ELDO E. ÁVILA

ATMOSPHERIC CHEMISTRY AND PHYSICS

COPERNICUS PUBLICATIONS

Lugar: Gottingen; Año: 2015 vol. 15 p. 16697 - 16714

1680-7316

This study reports measurements of deposition ice nuclei (IN) concentration at ground level during the period July-December 2014 in Córdoba, Argentina. The measurements were carried out at temperature of -25 °C and at 15 % supersaturation over ice. They were performed on days with different thermodynamic conditions, including rainy days. The effect of the relative humidity at ground level (RHamb) on the IN concentration was analyzed. The number of IN activated varied from 1 L-1 at RHamb of 25 % to 30 L-1 at RHamb of 90 %. In general, a linear trend between the IN concentration and the RHamb was found, suggesting that this variable must be related to the ability of the aerosols acting as IN. These results are consistent with previous results. From the backward trajectories analysis, it was found that the link between IN concentration and RHamb is independent of the origin of the air masses. The role of nucleation occurring in pores and cavities was discussed as possible mechanism to explain the increase on the IN concentration during high ambient relative humidity events.