A Prototype Method for Diagnosing High Ice Water Content in Near-Real-Time Using Passive Satellite Imagery

At least one hundred jet engine power loss events have occurred since 1990 at altitudes where conventional airframe icing is extremely unlikely. Recent research suggests that these events may be triggered by ingestion of high concentrations of small ice particles into the engine. This phenomenon, now dubbed ice crystal icing (ICI), typically happens in the vicinity of convective clouds which can loft large amounts of small ice crystals into the upper troposphere. Because the particles can be very small (~40 microns), they go undetected by onboard weather radar and hence conditions can appear benign at flight level. The High Altitude Ice Crystals – High Ice Water Content (HAIC-HIWC) field experiments in Darwin, Australia, and Cayenne, French Guiana, were organized to collect in-situ measurements of ice water content in order to better understand how these events are triggered and how they may be avoided. This paper presents a method to identify high ice water content conditions using multi-spectral imagery from passive geostationary satellites, cloud property retrievals from the NASA Langley Satellite ClOud and Radiative Property retrieval System (SatCORPS), and a satellite-derived database of overshooting top (OT) detections over the Darwin and Cayenne regions. The satellite observations and in-situ total water content measurements from the HAIC-HIWC experiments were used to develop a probabilistic indicator of HIWC and the method is demonstrated using rapid scan imagery from the Multi-Functional Transport Satellite (MTSAT-1R). Although HIWC, i.e., IWC > 1-2 g m-3, encounters were relatively uncommon during the experiments, most occurred within ~60 km of evident convection. Future application to next-generation imagers with high temporal resolution such as Himawari-8 and GOES-R is anticipated.