The Variability of Airfield Visibility

The Variability of Airfield Visibility PDF Author: Donald A. Chisholm
Publisher:
ISBN:
Category : Airports
Languages : en
Pages : 36

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Book Description
In this paper some results are presented concerning temporal and spatial variability of automated visibility measurements along a runway in conjunction with tower measurements. Comparisons are also made with variability statistics drawn from multi-transmissometer systems evaluated for the FAA.

The Variability of Airfield Visibility

The Variability of Airfield Visibility PDF Author: Donald A. Chisholm
Publisher:
ISBN:
Category : Airports
Languages : en
Pages : 36

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Book Description
In this paper some results are presented concerning temporal and spatial variability of automated visibility measurements along a runway in conjunction with tower measurements. Comparisons are also made with variability statistics drawn from multi-transmissometer systems evaluated for the FAA.

Air Force Surveys in Geophysics

Air Force Surveys in Geophysics PDF Author:
Publisher:
ISBN:
Category : Geophysics
Languages : en
Pages : 150

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Objective Prediction of Fine Scale Variations in Radiation Fog Intensity

Objective Prediction of Fine Scale Variations in Radiation Fog Intensity PDF Author: William Richard Tahnk
Publisher:
ISBN:
Category : Airports
Languages : en
Pages : 44

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Book Description
An examination of objective forecast techniques using sensor equivalent visibility to forecast fine scale variations in visibility was conducted with approximately two yr of radiation fog data collected in the AFCRL mesonet-work. Using stepwise screening regression and Regression Estimation of Event Probability (REEP) techniques, the results demonstrated the usefulness of a network of remote sensors around an airfield in objectively predicting short time scale fluctuations of airfield runway visibility. The REEP technique in particular generated exceedance probabilities that display positive skill relative to a conditional climatology model (Markov) of proven validity. Skill by subjective forecasters was also demonstrated using the REEP output as guidance in the generation of short-range forecasts out to one hr. The necessity for additional network stations away from the runway was demonstrated since statistical techniques utilizing runway visibility observations only, when applied to independent data, showed large negative skill relative to the Markov model in contrast to positive skill achieved using 8 network stations of varying distances out to 16 km from the runway.

Surface Aviation Observations (SAO) US Code

Surface Aviation Observations (SAO) US Code PDF Author: United States. Department of the Air Force
Publisher:
ISBN:
Category : Meteorology in aeronautics
Languages : en
Pages : 84

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Development and Calibration of the Forward Scatter Visibility Meter

Development and Calibration of the Forward Scatter Visibility Meter PDF Author: H. Stuart Muench
Publisher:
ISBN:
Category : Calibration
Languages : en
Pages : 44

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Book Description
A new visibility instrument, the forward scatter visibility meter, has been developed. This report describes the development of the instrument, including the various field tests. Some thirty instruments have been operationally deployed in a network of automatic weather stations near L.G. Hanscom Field in Bedford, Mass. Comparisons between field instruments and transmissometers yield differences of about plus or minus 19 percent. Comparisons with visual observations show differences of plus or minus 34 percent and greater. Analyses of individual cases uncovered difficulties with the response time of observers and with ability to diagnose spatially varying visibility. The accuracy of visibility measurements is assessed and the report concludes by looking at the future of visibility instruments. (Author).

Objective Prediction of Mesoscale Variations of Sensor Equivalent Visibility During Advective Situations

Objective Prediction of Mesoscale Variations of Sensor Equivalent Visibility During Advective Situations PDF Author: Donald A. Chisholm
Publisher:
ISBN:
Category : Airports
Languages : en
Pages : 36

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Book Description
The Hanscom AFB mesonetwork was established to examine the potential forecasting benefits to be derived from automated mesoscale observations. Experiments were set up to evaluate three objective procedures for prediction short-period (15 to 60 min) fluctuations in sensor equivalent visibility against a specialized conditional climatology model. The procedures evaluated were: a translation technique based on vectors determined by tracking mesoscale disturbances objectively, an advection technique which utilized forecast wind fields from a limited-area fine-mesh model, and a simple area-averaged trend technique. Data from 24 episodes of reduced visibility gathered during the 1972-74 period of mesonetwork operations were used to evaluate the techniques. The translation and area-averaged trend technique yielded positive skill relative to the conditional climatology model, while the advection technique did not. Although there were episodes in which the spatial selectivity of the translation technique yielded significant improvements, the trend technique was an overall better forecast indicator, especially when one considers its relative simplicity. (Author).

Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 798

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Instrumentation Papers

Instrumentation Papers PDF Author:
Publisher:
ISBN:
Category : Aeronautical instruments
Languages : en
Pages : 424

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Circular

Circular PDF Author:
Publisher:
ISBN:
Category : Meteorology
Languages : en
Pages : 290

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A Demonstration Test of the Modular Automated Weather System (MAWS)

A Demonstration Test of the Modular Automated Weather System (MAWS) PDF Author: Donald A. Chisholm
Publisher:
ISBN:
Category : Automatic meteorological stations
Languages : en
Pages : 90

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Book Description
A microprocessor-based automated airfield weather observing and forecasting system called MAWS (Modular Automated Weather System) was developed to demonstrate the feasibility of modernizing many of the observing and forecasting functions performed in operational base weather stations. Scott Air Force Base, Illinois, was chosen as the demonstration site and operations were conducted from January 1977 through January 1979. Weather sensors at five observation sites around the airfields were polled several times each minute, the data transmitted over commercial, voice-grade telephone lines to a central supervisory microprocessor where the data were suitably collated, averaged and formatted for display on alpha-numeric display devices at key locations and for magnetic tape archiving for post analysis. The demonstration confirmed that modernized weather support can be largely achieved with state-of-the-art, commercially available hardware/software. Such a system would be compatible with other automation efforts in civilian weather services and other C-cubed efforts in the DOD. The advantage of spatially and temporally detailed weather information in marginal and adverse situations was documented. Sensor siting considerations were addressed in relation to specific weather elements and observational requirements. The contributions of automated met watch procedures and short-range guidance forecasts of RVR landing minima were demonstrated. Feedback on system performance and acceptability was obtained from cognizant AWS offices.