ML-CIRRUS - the HALO mission on mid latitude cirrus clouds

Abstract

Clouds are a major source of uncertainty in current climate predictions. In particular, observations of cirrus cloud variability in distinct meteorological regimes and of contrail cirrus are prone to substantial ambiguities. Here we present results of the ML-CIRRUS mission with the German atmospheric science community aircraft HALO. The first in-situ cloud mission with the new high altitude long range aircraft combined a state-of-the-art cloud instrumentation consisting of 9 wing station probes with a novel aerosol, trace gas and radiation instrumentation and a water vapor differential absorption LIDAR inside the cabin. Further, a counter flow virtual impactor system designed for HALO allowed for the detection of ice residuals. In addition, models were specifically developed to support flight planning by forecasts of the occurrence and properties of natural cirrus (CLAMS, ECMWF) and frontal cirrus (WCB-ETH), as well as of aircraft induced cloudiness (CoCiP).