Scientists in ACLOUD expedition are trying to get new insight into the rapid warming taking place in the arctic (the arctic amplification). ACLOUD employs two Basler BT-67 aircrafts (Polar 5 & 6) - one equipped with in-situ instrumentation and one for remote sensing. Coordinated flights are taking place from Longyearbyen, Svalbard, targeting arctic clouds from northern Atlantic to sea ice north of Svalbard. Altogether 80 flight hours have been designated for the project.