Response of Cloud Microphysical Instruments to Aircraft Icing Conditions

Response of Cloud Microphysical Instruments to Aircraft Icing Conditions PDF

Author: Morton Glass

Publisher:

Published: 1981

Total Pages: 64

ISBN-13:

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A series of passes on 6 December 1979 through multilayered-supercooled stratiform and stratocumulus clouds by the Air Force Geophysics Laboratory's instrumented C-130E cloud physics research aircraft is used to evaluate a Rosemount Ice Detector. The response of the detector to icing conditions is compared with measurements from a J-W liquid water content meter and the Knollenberg Axial Scattering Spectrometer Probe (ASSP). A procedure to adjust for zero drift of the J-W instrument is developed. Comparison of liquid water measurements from the J-W and from the ASSP indicate that these data are highly correlated and similar in magnitude. A procedure for extracting useful information from the Rosemount Ice detector has been developed. The icing conditions in the cloud systems studied are typical of the range of conditions in winter stratiform clouds. Liquid water (LWC) values of 0.3 g/cu m and median volume diameters of 15 micrometers were most frequently observed. The results of the analysis show that the Rosemount Ice Detector is a sensitive indicator of the fluctuations of liquid water in clouds with LWC not exceeding 0.8 g/cu m -3.

Response of Cloud Microphysical Instruments to Aircraft Icing Conditions

Response of Cloud Microphysical Instruments to Aircraft Icing Conditions PDF

Author: Morton Glass

Publisher:

Published: 1981

Total Pages: 57

ISBN-13:

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A series of passes on 6 December 1979 through multilayered-supercooled stratiform and stratocumulus clouds by the Air Force Geophysics Laboratory's instrumented C-130E cloud physics research aircraft is used to evaluate a Rosemount Ice Detector. The response of the detector to icing conditions is compared with measurements from a J-W liquid water content meter and the Knollenberg Axial Scattering Spectrometer Probe (ASSP). A procedure to adjust for zero drift of the J-W instrument is developed. Comparison of liquid water measurements from the J-W and from the ASSP indicate that these data are highly correlated and similar in magnitude. A procedure for extracting useful information from the Rosemount Ice detector has been developed. The icing conditions in the cloud systems studied are typical of the range of conditions in winter stratiform clouds. Liquid water (LWC) values of 0.3 g/cu m and median volume diameters of 15 micrometers were most frequently observed. The results of the analysis show that the Rosemount Ice Detector is a sensitive indicator of the fluctuations of liquid water in clouds with LWC not exceeding 0.8 g/cu m -3. (Author).

Remote Sensing of In-flight Icing Conditions

Remote Sensing of In-flight Icing Conditions PDF

Author: Charles Curtis Ryerson

Publisher:

Published: 2000

Total Pages: 78

ISBN-13:

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Remote-sensing systems that map aircraft icing conditions in the flight path from airports or aircraft would allow icing to be avoided and exited. Icing remote-sensing system development requires consideration of the operational environment, the meteorological environment, and the technology available. Operationally, pilots need unambiguous cockpit icing displays for risk management decision-making. Human factors, aircraft integration, integration of remotely sensed icing information into the weather system infrastructures, and avoid-and-exit issues need resolution. An icing remote-sensing system detects cloud and precipitation liquid water, drop size, and temperature. An algorithm is needed to convert these conditions into icing potential estimates for cockpit display. Specification development requires that magnitudes of cloud microphysical conditions and their spatial and temporal variability be understood at multiple scales. The core of an icing remote-sensing system is the technology that senses icing microphysical conditions. Radar and microwave radiometers penetrate clouds and can estimate liquid water and drop size. Airport-based radar or radiometers are the most viable near-term technologies. A radiometer that profiles cloud liquid water, and experimental techniques to use radiometers horizontally, are promising. The most critical operational research needs are to assess cockpit and aircraft system integration, develop avoid-and-exit protocols, assess human factors, and integrate remote-sensing information into weather and air traffic control infrastructures. This report reviews operational, meteorological, and technological considerations in developing the capability to remotely map in-flight icing conditions from the ground and from the air.

Some Microphysical Processes Affecting Aircraft Icing

Some Microphysical Processes Affecting Aircraft Icing PDF

Author: Hugh J. Sweeney

Publisher:

Published: 1985

Total Pages: 52

ISBN-13:

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This report summarizes work done as part of the aircraft icing probabilities program. It contains a look at icing in layer-type clouds, a comparison of Particle Measuring System (PMS)2-D data from two flights. and a look at additional data obtained from researchers in the Federal Republic of Germany. The parameters measured in a warm and cold layer-type cloud near Peoria, IL are analyzed and compared. Liquid water content (LWC), cloud depth, particle diameter and particle concentration are compared. Variations of these parameters are compared. In mature clouds, where droplet sizes are approximately equal, the LWC is directly related to the number concentration. The icing rate, LWC and droplet size all increase as a function of height above cloud base. Synoptic patterns and PMS 2-D data obtained on two flights are compared. The first flight, made near Greensboro, NC was in an area of heavy precipitation. The large particles present produced very little icing. The other flight, near Flint, MI was in an area which was experiencing only spotty precipitation. The aircraft, however, experienced moderate icing. Data gathered on aircraft observations in the Federal Republic of Germany are examined. The data show that in strong icing situations, there are many particles with diameters of 10 to 20 microns. The results match those obtained by our research flights. Keywords: Cloud physics; Aviation meteorology; Particle distribution.