AMCCA: Airborne Measurements of Charged Cloud and Aerosol

FAAM Research Runway project to take measurements of cloud and aerosol properties over the UK during summer 2023, in coordination with radiosonde measurements of electric charge released from the University of Reading Atmospheric Observatory.

PI: Hripsime (Ripsi) Mkrtchyan, Co-Is: Dr Claire Ryder, Dr Keri Nicoll.

This project will investigate how the natural electric fields always present in the atmosphere affect cloud and aerosol processes. These include the increased sticking probability of colliding droplets which are charged, an additional electrical uplift force reducing the rate of dust deposition, and enhanced removal of charged dust and aerosol by water droplets. Such effects are known to occur in and around stratiform cloud and above and within atmospheric dust layers.

We are targetting two different weather conditions: firstly stable, highly likely stratocumulus or stratus cloud, which is typical under anticyclonic conditions. We aim to sample the cloud edges with the FAAM aircraft to accurately measure the cloud particle sizes, while the radiosondes from Reading measure the cloud edge charging.

Secondly, we will target a case of Saharan dust being transported to the UK. This is less likely to occur, but would offer extremely novel measurements. We aim to sample the size distribution of long-range transported desert dust, coincident with charging observations from a radiosonde balloon. Charging of dust may counteract the downwards force of gravity, enabling it to remain airborne for longer.

These flights will allow us to identify which in-cloud processes are affected by electric charge, and how dust size distributions relate to charge, which has never been quantified experimentally before.