Aerosol concentrations determine the height of warm rain and ice initiation in convective clouds over the Amazon basin

摘要

We have investigated how aerosols affect the height above cloud base of rain and ice hydrometeor Initiation and the subsequent vertical evolution of cloud droplet size and number concentrations in growing convective cumulus. For this purpose we used in situ data of hydrometeor size distributions measured with instruments mounted on HALO aircraft during the ACRIDICON CHUVA campaign over the Amazon during September 2014. The results show that the height of rain initiation by collision and coalescence processes is linearly correlated with the number concentration of droplets nucleated at cloud base.