Technical Note: New particle formation event forecasts during PEGASOS-Zeppelin Northern mission 2013 in Hyytiälä, Finland

Abstract

Abstract. New particle formation (NPF) occurs frequently in the global atmosphere. During recent years detailed laboratory experiments together with intensive field observations in different locations have provided insights into the vapours responsible for the initial formation of particles and their subsequent growth. In this regard, the importance of sulphuric acid, stabilizing bases such as ammonia and amines as well as extremely low volatile organics have been proposed. The instrumentation to observe freshly formed aerosol particles has developed to a stage where the instruments can be implemented as part of airborne platforms, such as aircrafts or a Zeppelin-type airship. Flight measurements are technically more demanding and require a greater detail of planning than field studies at the ground level. The high cost of flight hours, limited time available during a single research flight for the measurements and different instrument payloads in Zeppelin airship for various flight missions demanded an analysis tool that would forecast whether or not there is a good chance for a NPF event. Here we present a generalized methodology to derive NPF event probability that was used to optimise flying hours during Zeppelin campaign in Finland during the PEGASOS-Zeppelin Northern mission in 2013. Based on the existing knowledge we derived a method for estimating the nucleation probability that utilizes forecast air mass trajectories, weather forecasts and air quality model predictions. With the forecast tool we were able to predict the occurrence of NPF events for the next day with more than 90% success rate (10 out of 11 NPF event days correctly predicted).