Ice clouds and aviation impacts
Since at least the 1990s, commercial aircraft occasionally experience so-called In-Service icing events while flying in the vicinity of deep convective clouds. Such events are accompanied by loss of thrust and sometimes even complete shutdown of engines. In order to better understand what is going on during such events, and in preparation of expected changes in regulations for flying in such conditions, the European Union has funded a 4-year pan-European project HAIC that started in 2012.
KNMI has been invited to participate in HAIC because of their knowledge and expertise of detecting the physical properties of clouds based on geostationary satellite measurements. Within the project, a High Ice Water Content mask has been developed that identifies atmospheric cloud conditions where the occurrence of high ice water content is likely. High ice water content is a necessary prerequisite for the occurrence of InService icing events.
Extensive evaluation of the High IWC mask against both in situ measurements of IWC obtained from HAIC field campaigns, and against remotely sensed IWC, has shown that that the mask is successful in detecting atmospheric cloud conditions under which High IWC occurs, with rate of detection of better than 80%, with even better detection rates of 90% - 99% for high altitude clouds and larger convective systems.
In addition, the High IWC mask has been made available in near-real time on the KNMI CPP web portal. The capacity to provide CPP data in near real time will become useful in the near future as part of the EU Single European Sky ATM Research (SESAR; ATM = Air Traffic Management) programme, in particular the development of 4D (i4D) trajectory management – connecting aircraft and ground systems to continuously optimize the aircraft trajectory.
HIAC concluded in January 2017. For more information, see http://www.haic.eu.