Progress towards the remote sensing of aircraft icing hazards

Abstract

NASA has teamed with the FAA, DoD, industry, and academia for research into the remote detection and measurement of atmospheric conditions leading to aircraft icing hazards. The ultimate goal of this effort is to provide pilots, controllers, and dispatchers sufficient information to allow aircraft to avoid or minimize their exposure to the hazards of in-flight icing. Since the hazard of in-flight icing is the outcome of aircraft flight through clouds containing supercooled liquid water and strongly influenced by the aircraft's speed and configuration and by the length of exposure, the hazard can't be directly detected, but must be inferred based upon the measurement of conducive atmospheric conditions. Therefore, icing hazard detection is accomplished through the detection and measurement of liquid water in regions of measured sub-freezing air temperatures. The icing environment is currently remotely measured from the ground with a system fusing radar, lidar, and multi-frequency microwave radiometer sensors. Based upon expected ice accretion severity for the measured environment, a resultant aircraft hazard is then calculated. Because of the power, size, weight, and view angle constraints of airborne platforms, the current ground-based solution is not applicable for flight. Two current airborne concepts are the use of either multi-frequency radiometers or multi-frequency radar. Both ground-based and airborne solutions are required for the future since ground-based systems can provide hazard detection for all aircraft in airport terminal regions while airborne systems will be needed to provide equipped aircraft with flight path coverage between terminal regions.

Charting the space of 3D CFTs with a continuous global symmetry

“…Indeed, the U (1) R-symmetry current J µ is embedded in the Ferrara-Zumino supermultiplet, which also contains the energy momentum tensor as a super-descendant. The study of J µ correlation functions will provide a universal handle on all local SCFTs, allowing in principle to discover theories we currently know nothing about [55].…”

From CloudSat‐CALIPSO to EarthCare: Evolution of the DARDAR cloud classification and its comparison to airborne radar‐lidar observations

“…Strong backscatter regions are composed either of warm liquid water, supercooled water, ice in high concentration, or a mix of them. Locating supercooled water layers is crucial as they represent a major weather hazard in aeronautics and can cause fatalities [ Reehorst et al , ]. Moreover, they have an influence on retrieval methods [ Delanoë and Hogan , ] and radiative transfer calculations [ Hogan et al , ].…”

Determining the Flight Icing Threat to Aircraft with Single-Layer Cloud Parameters Derived from Operational Satellite Data

“…The NIRSS icing retrieval uses ground-based remote sensing data to estimate the FIT over a single surface site (Reehorst et al 2009) in Cleveland, Ohio. Although icing is not measured directly, NIRSS provides an objective estimate using active and passive remote sensors (i.e., microwave radiometer, cloud radar, and ceilometer) and thus has the capability to provide vertical resolution, with some assumptions.…”

“…The NIRSS was developed to demonstrate a ground-based remote sensing system concept that could provide accurate detection and warning of inflight icing conditions in the near-airport environment. The system fuses data from radar, lidar, and multifrequency microwave radiometer sensors to quantify the icing environment and compute the icing hazard (Reehorst et al 2009) on the basis of the expected ice accretion severity for the measured environment (Politovitch 2003). Although the system does not measure icing directly, this remote sensing concept appears to offer some advantages for satellite validation that are not found elsewhere.…”