A Prototype Method for Diagnosing High Ice Water Content Probability Using Satellite Imager Data

Cloud icing by mineral dust and impacts to aviation safety

Ice particles in high-altitude cold clouds can obstruct aircraft functioning. Over the last 20 years, there have been more than 150 recorded cases with engine power-loss and damage caused by tiny cloud ice crystals, which are difficult to detect with aircraft radars. Herein, we examine two aircraft accidents for which icing linked to convective weather conditions has been officially reported as the most likely reason for catastrophic consequences. We analyze whether desert mineral dust, known to be very efficient ice nuclei and present along both aircraft routes, could further augment the icing process. Using numerical simulations performed by a coupled atmosphere-dust model with an included parameterization for ice nucleation triggered by dust aerosols, we show that the predicted ice particle number sharply increases at approximate locations and times of accidents where desert dust was brought by convective circulation to the upper troposphere. We propose a new icing parameter which, unlike existing icing indices, for the first time includes in its calculation the predicted dust concentration. This study opens up the opportunity to use integrated atmospheric-dust forecasts as warnings for ice formation enhanced by mineral dust presence.

Satellites See the World’s Atmosphere

Satellite meteorology is a relatively new branch of the atmospheric sciences. The field emerged in the late 1950s during the Cold War and built on the advances in rocketry after World War II. In less than 70 years, satellite observations have transformed the way scientists observe and study Earth. This paper discusses some of the key advances in our understanding of the energy and water cycles, weather forecasting, and atmospheric composition enabled by satellite observations. While progress truly has been an international achievement, in accord with a monograph observing the centennial of the American Meteorological Society, as well as limited space, the emphasis of this chapter is on the U.S. satellite effort.

Detecting Clouds Associated with Jet Engine Ice Crystal Icing

Over 150 jet engine power-loss and damage events have been attributed to a phenomenon known as Ice Crystal Icing (ICI) during the past two decades. Attributed to ingestion of large numbers of small ice particles into the engine core, typically these events have occurred at high altitudes near large convective systems in tropical air masses. In recent years there have been substantial international efforts by scientists, engineers, aviation regulators and airlines to better understand the relevant meteorological processes, solve critical engineering questions, develop new certification standards, and devise mitigation strategies for the aviation industry. One area of research is the development of nowcasting techniques based on available remote sensing technology and cloud models to identify potential areas of high ice water content (HIWC) and enable the provision of alerts to the aviation industry. An international consortium of researchers has investigated various methods for detecting the HIWC conditions associated with ICI. Multiple techniques have been developed using geostationary and polar orbiting satellite products, numerical weather prediction model fields, and ground based radar data as the basis for HIWC products. Targeted field experiments in tropical regions with high incidence of ICI events have provided data for product validation and refinement of these methods. Beginning in 2015, research teams have assembled at a series of bi-annual workshops to exchange ideas and standardize methods for evaluating performance of HIWC detection products. This paper provides an overview of the approaches used and the current skill for identifying HIWC conditions. Recommendations for future work in this area are also presented.