Source: http://www.science.gov/topicpages/a/airport+weather+minimums.html
Timestamp: 2016-10-24 09:08:45
Document Index: 328110430

Matched Legal Cases: ['§ 121', '§ 121', '§ 121', '§ 121', '§ 121', 'art 946', 'art 946']

airport weather minimums: Topics by Science.gov
Sample records for airport weather minimums
76 FR 67018 - Notice to Manufacturers of Airport In-Pavement Stationary Runway Weather Information Systems
... Federal Aviation Administration Notice to Manufacturers of Airport In-Pavement Stationary Runway Weather... of In-Pavement Stationary Runway Weather Information Systems. SUMMARY: Projects funded under the... Active or Passive In- Pavement Stationary Runway Weather Information Systems that meet the...
14 CFR 121.649 - Takeoff and landing weather minimums: VFR: Domestic operations.
... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Takeoff and landing weather minimums: VFR... Flight Release Rules § 121.649 Takeoff and landing weather minimums: VFR: Domestic operations. (a) Except... weather minimums in this section do not apply to the VFR operation of fixed-wing aircraft at any of...
... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Takeoff and landing weather minimums: VFR... Flight Release Rules § 121.649 Takeoff and landing weather minimums: VFR: Domestic operations. (a) Except... weather minimums in this section do not apply to the VFR operation of fixed-wing aircraft at any of...
... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Takeoff and landing weather minimums: VFR... Flight Release Rules § 121.649 Takeoff and landing weather minimums: VFR: Domestic operations. (a) Except... weather minimums in this section do not apply to the VFR operation of fixed-wing aircraft at any of...
... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Takeoff and landing weather minimums: VFR... Flight Release Rules § 121.649 Takeoff and landing weather minimums: VFR: Domestic operations. (a) Except... weather minimums in this section do not apply to the VFR operation of fixed-wing aircraft at any of...
... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Takeoff and landing weather minimums: VFR... Flight Release Rules § 121.649 Takeoff and landing weather minimums: VFR: Domestic operations. (a) Except... weather minimums in this section do not apply to the VFR operation of fixed-wing aircraft at any of...
Simulated flight through JAWS wind shear - In-depth analysis results. [Joint Airport Weather Studies
Frost, W.; Chang, H.-P.; Elmore, K. L.; Mccarthy, J.
The Joint Airport Weather Studies (JAWS) field experiment was carried out in 1982 near Denver. An analysis is presented of aircraft performance in the three-dimensional wind fields. The fourth dimension, time, is not considered. The analysis seeks to prepare computer models of microburst wind shear from the JAWS data sets for input to flight simulators and for research and development of aircraft control systems and operational procedures. A description is given of the data set and the method of interpolating velocities and velocity gradients for input to the six-degrees-of-freedom equations governing the motion of the aircraft. The results of the aircraft performance analysis are then presented, and the interpretation classifies the regions of shear as severe, moderate, or weak. Paths through the severe microburst of August 5, 1982, are then recommended for training and operational applications. Selected subregions of the flow field defined in terms of planar sections through the wind field are presented for application to simulators with limited computer storage capacity, that is, for computers incapable of storing the entire array of variables needed if the complete wind field is programmed.
Initial Results of Coupling the Output of a Regional Weather Model and a Localized Computational Fluid Dynamics Model at the Atlantic City International Airport
Trout, Joseph; Manson, J. Russell; Rios, Manny; King, David; Decicco, Nicholas
Wake Vortex Turbulence is the turbulence generated by an aircraft in flight. This turbulence is created by vortices at the tips of the wing that may decay slowly and persist for several minutes after creation. The strength, formation and lifetime of the turbulence and vortices are effected by many things including the weather. Here we present the preliminary results of an investigation of low level wind fields generated by the Weather Research and Forecasting Model and an analysis of historical data. The simulations are used as inputs for the computational fluid dynamics model (OpenFoam) that will be used to investigate the effect of weather on wake turbulence. The initial results of the OpenFoam model are presented elsewhere. Presented here are the initial results from a research grant, ``A Pilot Project to Investigate Wake Vortex Patterns and Weather Patterns at the Atlantic City Airport by the Richard Stockton College of NJ and the FAA''.
Winter synoptic weather types in Catalonia (NE Spain) and their linkage with minimum temperature anomalies
Serra, C.; Mills, G. Fernàndez; Periago, M. C.; Lana, X.
An objective classification of winter synoptic weather types in Catalonia (NE Spain) is obtained by means of the principal component analysis of daily variables followed by cluster analysis based on Average Linkage and K-Means methods. The period analysed includes days belonging to December, January and February, from 1976 to 1980. The data list consists of thermal, pressure, cloud cover, humidity, wind and precipitation values recorded at four different stations in Catalonia. The classification includes 14 clusters which accurately explain the winter synoptic variety of the country. All cluster features are discussed in detail and a study concerning transitions between these clusters is presented. Three groups (1, 3 and 7) are related to high pressure weather types, clusters 4, 5 and 8 to cold sectors of mid-latitude depressions and clusters 2 and 9 can be associated with cyclonic conditions with western circulation. The weather types related to extended precipitation are included in clusters 6 and 10 which are linked to eastern surface circulation. The obtained classification is then applied in a study concerning daily minimum temperature anomalies. The spatial distribution of these anomalies are analysed for each significant weather type. The clusters related to widely extended frost risk are finally identified (groups 4, 8 and 14).
The influence of weather types on the monthly average maximum and minimum temperatures in the Iberian Peninsula
Peña-Angulo, D.; Trigo, R. M.; Cortesi, N.; González-Hidalgo, J. C.
The climate of the Iberian Peninsula is highly variable due to geographic and atmospheric factors. To better understand and characterize this variability in this work a stepwise regression procedure is used to model the relationship between the atmospheric circulation patterns (expressed by weather types) and the monthly mean value of maximum and minimum temperatures in the Iberian Peninsula (1950-2010). The study uses a temperature database with high spatial resolution that allows the estimation of the type and strength of the relationship between weather types and temperatures, and also the definition of spatial areas with specific behaviors for each month. The results show that estimations are better for Tmin than Tmax, during winter months than summer ones, and in coastal areas than inland. The analyses of directional weather types and temperature show a generalized adiabatic processes across Iberian Peninsula affecting Tmax, not detected in Tmin.
Kumar, Abhikesh; Kumar, Sushil
The effects of the solar flares and the geomagnetic storms (disturbance storm time ( Dst) < -50 nT) during December 2006 to 2008, a period during the unprecedented solar minimum of solar cycles 23 and 24, have been examined on sub-ionospheric very low frequency (VLF) signals from NWC (19.8 kHz), NPM (21.4 kHz), VTX (18.2 kHz), and NLK (24.8 kHz) transmitters monitored at Suva (18.2° S, 178.4° E), Fiji. Apart from the higher class solar flares (C to X), a solar flare of class B8.5 also produced enhancements both on the amplitude and phase. The amplitude enhancements in NLK, NPM, and NWC signals as a function of peak solar flare X-ray flux in decibel (dB; relative to 1 μW/m2) shows that the relationship curve is steeper and quite linear between the flare power levels of 0 to 15 dB; below 0 dB, the curve gets less steep and flattens towards -5 dB flare power level, while it also gets less steep above 15 dB and almost flattens above 20 dB. In general, the level of amplitude enhancement for NLK signal is higher than that for NPM and NWC signals for all solar flares. The enhancement in the amplitude and phase of VLF signals by solar flares is due to the increase in the D-region electron density by the solar flare-produced extra ionization. The modeling of VLF perturbations produced by B8.5 and C1.5 classes of solar flares on 29 January 2007 using LWPC (Long Wave Propagation Capability) V2.1 codes show that reflection height ( H') was reduced by 0.6 and 1.2 km and the exponential sharpness factor ( β) was raised by 0.010 and 0.005 km-1, respectively. Out of seven storms with Dst < -50 nT, only the intense storm of 14 to 16 December 2006 with a minimum Dst of -145 nT has shown a clear reduction in the signal strength of NWC and NPM sub-ionospheric signals due to storm-induced reduction in the D-region electron density.
15 CFR Appendix B to Part 946 - Airport Tables
... OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE REGULATIONS OF THE NATIONAL WEATHER SERVICE MODERNIZATION OF THE NATIONAL WEATHER SERVICE Pt. 946, App. B Appendix B to Part 946—Airport Tables “A”...
Wang, Yao; Kulkarni, Deepak
Comparison of Five Weather Forecast Methods at Four California Locations
Dempsey, D. P.; Garcia, O.; Frieberg, E.; Tidwell, W.; Chow, B.; Daquigan, D.; Long, D.; Tan, K.
In this project we compare five methods of forecasting maximum and minimum temperature and probability of precipitation at four California locations: California Academy of Sciences in San Francisco, Oakland Museum, Sacramento Executive Airport, and Truckee Airport. The five methods are applied to make 24-hour forecasts twice weekly during the period from August 18 to December 2, 2003. The five forecast methods include: (1) Persistence. A persistence forecast assumes that tomorrow's weather will be the same as today's. (2) Climatology. Our climatology-based forecasts use weather conditions for the day at or very near each of the four locations, averaged over the 30-year period from 1971 to 2000. (3) Official National Weather Service (NWS) forecasts. We use the official NWS forecasts for Oakland Museum, Sacramento Executive Airport, and Truckee Airport. For The California Academy of Sciences (CAS) we use the NWS's new Prototype Digital Forecast for the CAS's latitude and longitude. (4) Individual student forecasts, made by four 10th grade students from San Francisco's Burton High School. They consulted the most recent meteograms, satellite images, soundings, synoptic analyses, and computer model forecasts, as well as climatology, persistence, and NWS forecasts. (5) A consensus of student forecasts, comprising the average of the four student forecasts. We calculate forecast error by squaring the difference between a forecast and the verifying observation, and compare the forecast methods based on these errors.
14 CFR 91.1039 - IFR takeoff, approach and landing minimums.
.... 91.1039 Section 91.1039 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... airport unless— (1) Either that airport or the alternate airport has a weather reporting facility operated by the U.S. National Weather Service, a source approved by the U.S. National Weather Service, or...
...) No pilot may take off from an alternate airport unless the weather conditions are at least equal to... operations. (a) No pilot may takeoff an airplane from an airport that is not listed in the operations specifications unless— (1) The airport and related facilities are adequate for the operation of the airplane;...
Kani, T.; Isozaki, Y.
We report a detailed secular change of the middle Middle to early Late Permian seawater 87Sr/86Sr ratio for and Akasaka and Kamura carbonates (Japan) deposited on mid-Pansalassan seamounts and for Shizipo carbonates (South China) deposited on the shallow marine shelf. In these coeval sections, extremely low values (<0.7069; the lowest values of the Phanerozoic) continued from upper Wordian (middle Middle Permian) to the topmost Capitanian (upper Middle Permian) barren interval immediately below the Middle-Late Permian boundary characterized by the major crisis of large-tested fusulines and rugose corals. Immediately after ca. 5 m.y.-long minimum interval, the major rise in 87Sr/86Sr was started and the rate of the rise (0.00007/m.y.) continued in period of time containing 21 m.y. until early Triassic (~239 Ma), that is faster than the Cenozoic major rise (0.00003/m.y.).　The most significant shift through Phanerozoic in Sr isotope trend can be explained by the remarkable changes in continental erosion/weathering rate; in particular, by the onset of glaciation and the following deglaciation, that is supported by global sea level change, in addition to the initial doming/rifting of Pangea. After the Capitanian cooling, the long-term climatic regime shifted to a warmer one during which inland ice sheet was removed to expose old crustal silicates for to erosion/weathering. A mantle plume impingiment might lead a domal uplift that accelerate weathering. Highly radiogenic continental Sr could enter the ocean along the new drainage systems developed with the rifting.
... that airport when used as an alternate airport, for each pilot in command of a turbine-powered airplane... the lowest straight-in landing minimums, unless otherwise restricted, if— (1) The wind direction...
... that airport when used as an alternate airport, for each pilot in command of a turbine-powered airplane... minimums, unless otherwise restricted, if— (1) The wind direction and velocity at the time of takeoff...
Li, Cheng; Wang, Shuigen; Pang, Zhaofeng; Zhao, Baojun
Numerical Model Simulation of Atmosphere above A.C. Airport
Lutes, Tiffany; Trout, Joseph
In this research project, the Weather Research & Forecasting (WRF) model from the National Center for Atmospheric Research (NCAR) is used to investigate past and present weather conditions. The Atlantic City Airport area in southern New Jersey is the area of interest. Long-term hourly data is analyzed and model simulations are created. By inputting high resolution surface data, a more accurate picture of the effects of different weather conditions will be portrayed. Currently, the impact of gridded model runs is being tested, and the impact of surface characteristics is being investigated.
Measuring weather for aviation safety in the 1980's
Requirements for an improved aviation weather system are defined and specifically include the need for (1) weather observations at all airports with instrument approaches, (2) more accurate and timely radar detection of weather elements hazardous to aviation, and (3) better methods of timely distribution of both pilot reports and ground weather data. The development of the discrete address beacon system data link, Doppler weather radar network, and various information processing techniques are described.
Enhanced Airport Capacity Through Safe, Dynamic Reductions in Aircraft Separation: NASA's Aircraft VOrtex Spacing System (AVOSS)
OConnor, Cornelius J.; Rutishauser, David K.
An aspect of airport terminal operations that holds potential for efficiency improvements is the separation criteria applied to aircraft for wake vortex avoidance. These criteria evolved to represent safe spacing under weather conditions conducive to the longest wake hazards, and are consequently overly conservative during a significant portion of operations. Under many ambient conditions, such as moderate crosswinds or turbulence, wake hazard durations are substantially reduced. To realize this reduction NASA has developed a proof-of-concept Aircraft Vortex Spacing System (AVOSS). Successfully operated in a real-time field demonstration during July 2000 at the Dallas Ft. Worth International Airport, AVOSS is a novel integration of weather sensors, wake sensors, and analytical wake prediction algorithms. Gains in airport throughput using AVOSS spacing as compared to the current criteria averaged 6%, with peak values approaching the theoretical maximum of 16%. The average throughput gain translates to 15-40% reductions in delay when applied to realistic capacity ratios at major airports.
Development and flight test of a weather radar precision approach concept
Clary, G. R.; Anderson, D. J.; Chisholm, J. P.
In order to make full use of the helicopter's unique capability of remote-site, off-airport landings, it would be desirable to employ a self-contained navigation system requiring minimum groundable-based equipment. For this reason, research is being conducted with the aim to develop the use of airborne weather radar as a primary navigation aid for helicopter approach and landing in instrument flight rules (IFR) conditions. Anderson et al. (1982) have reported about the first phase of this effort, taking into account the detection of passive ground-based corner reflectors with the aid of an 'echo processor'. The technology of passive-reflector detection in the overland environment provides the pilot with the range and bearing to the landing site. The present investigation is concerned with a second research phase, which was undertaken with the objective to develop and demonstrate the feasibility of a weather radar-based precision approach concept. Preliminary flight test results are considered.
Airport surveillance using a solid state coherent lidar
Huffaker, R. Milton; Hannon, Stephen M.
The utility of solid state coherent LIDAR was assessed in the following application areas: (1) wake vortices; (2) dry and wet microburst windshear; (3) gusts; (4) vertical and general wind profiling; and (5) cloud ceiling. The system performance model described was based on a concept definition, system sizing, measurement planning, and algorithm and graphics display development. Data were collected at the Kennedy Space Center and the National Weather Service site adjacent to Denver's Stapleton Airport.
The DLR Project - Weather & Flying
A project is introduced which aims at (a) providing timely, tailored and concise meteorological information especially for adverse weather as precisely as possible for air traffic control and management, airline operating centres, pilots, and airports, and (b) building automated flight control systems and evasion-manoeuvre methods to minimise the impact of adverse wind and wake conditions on the flight performance of an aircraft. Today ATM and ATC most of the time only react on adverse weather when the disruption has already happened or is just about to happen. A future air traffic management should pro-actively anticipate disruptive weather elements and their time scales well in advance to avoid or to mitigate the impact upon the traffic flow. But "weather” is not a technical problem that can be simply solved. Predicting the weather is a difficult and complex task and only possible within certain limits. It is therefore necessary to observe and forecast the changing state of the atmosphere as precisely and as rapidly as possible. Measures must be taken to minimise the impact of adverse weather or changing weather conditions on air traffic management and tactical manoeuvring, both on ground and onboard the aircraft. Weather and meteorological information (MET in short) is to be considered as an integral part of air traffic management. In 2008, DLR has initiated a major project "Wetter & Fliegen” (German for "Weather and Flying”) to address this inter¬disciplinary challenge. Its goal is to augment safety and efficiency of air transportation, thereby focusing on the two German hub airports in Frankfurt and München. This high-level goal shall be reached by two strands of work: a) The development of an Integrated Terminal Weather Systems (ITWS) for the air¬¬ports at Frankfurt and München to improve the detection and forecast of weather phenomena adversely affecting airport operations, including deep convection (thunderstorms, hail, wind), wake vortex, and
Improved Airport Noise Modeling for High Altitudes and Flexible Flight Operations
Forsyth, David W.; Follet, Jesse I.
The FAA's Integrated Noise Model (INM) is widely used to estimate noise in the vicinity of airports. This study supports the development of standards by which the fleet data in the INM can be updated. A comparison of weather corrections to noise data using INM Spectral Classes is made with the Boeing integrated method. The INM spectral class method is shown to work well, capturing noise level differences due to weather especially at long distances. Two studies conducted at the Denver International Airport are included in the appendices. The two studies adopted different approaches to modeling flight operations at the airport. When compared to the original, year 2000, results, it is apparent that changes made to the INM in terms of modeling processes and databases have resulted in improved agreement between predicted and measured noise levels.
This document describes operations associated with a set of flight experiments and demonstrations using a Boeing-757-200 research aircraft as part of low visibility landing and surface operations (LVLASO) research activities. To support this experiment, the B-757 performed flight and taxi operations at the Atlanta Hartsfield International Airport in Atlanta, GA. The test aircraft was equipped with experimental displays that were designed to provide flight crews with sufficient information to enable safe, expedient surface operations in any weather condition down to a runway visual range of 300 feet. In addition to flight deck displays and supporting equipment onboard the B-757, there was also a ground-based component of the system that provided for ground controller inputs and surveillance of airport surface movements. Qualitative and quantitative results are discussed.
Crawford, Winfred C.
The forecasters at the National Weather Service in Melbourne, FL, (NWS MLB) identified a need to make more accurate lightning forecasts to help alleviate delays due to thunderstorms in the vicinity of several commercial airports in central Florida at which they are responsible for issuing terminal aerodrome forecasts. Such forecasts would also provide safer ground operations around terminals, and would be of value to Center Weather Service Units serving air traffic controllers in Florida. To improve the forecast, the AMU was tasked to develop an objective lightning probability forecast tool for the airports using data from the National Lightning Detection Network (NLDN). The resulting forecast tool is similar to that developed by the AMU to support space launch operations at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) for use by the 45th Weather Squadron (45 WS) in previous tasks (Lambert and Wheeler 2005, Lambert 2007). The lightning probability forecasts are valid for the time periods and areas needed by the NWS MLB forecasters in the warm season months, defined in this task as May-September.
Demonstration of radar reflector detection and ground clutter suppression using airborne weather and mapping radar
Anderson, D. J.; Bull, J. S.; Chisholm, J. P.
A navigation system which utilizes minimum ground-based equipment is especially advantageous to helicopters, which can make off-airport landings. Research has been conducted in the use of weather and mapping radar to detect large radar reflectors overland for navigation purposes. As initial studies have not been successful, investigations were conducted regarding a new concept for the detection of ground-based radar reflectors and eliminating ground clutter, using a device called an echo processor (EP). A description is presented of the problems associated with detecting radar reflectors overland, taking into account the EP concept and the results of ground- and flight-test investigations. The echo processor concept was successfully demonstrated in detecting radar reflectors overland in a high-clutter environment. A radar reflector target size of 55 dBsm was found to be adequate for detection in an urban environment.
Radiometrics Corporation, headquartered in Boulder, Colorado, engaged in Small Business Innovation Research (SBIR) agreements with Glenn Research Center that resulted in a pencil-beam radiometer designed to detect supercooled liquid along flight paths -- a prime indicator of dangerous icing conditions. The company has brought to market a modular radiometer that resulted from the SBIR work. Radiometrics' radiometers are used around the world as key tools for detecting icing conditions near airports and for the prediction of weather conditions like fog and convective storms, which are known to produce hail, strong winds, flash floods, and tornadoes. They are also employed for oceanographic research and soil moisture studies.
Spirkovska, Lilly; Lodha, Suresh K.
The two official sources for aviation weather reports both provide weather information to a pilot in a textual format. A number of systems have recently become available to help pilots with the visualization task by providing much of the data graphically. However, two types of aviation weather data are still not being presented graphically. These are airport-specific current weather reports (known as meteorological observations, or METARs) and forecast weather reports (known as terminal area forecasts, or TAFs). Our system, Aviation Weather Environment (AWE), presents intuitive graphical displays for both METARs and TAFs, as well as winds aloft forecasts. We start with a computer-generated textual aviation weather briefing. We map this briefing onto a cartographic grid specific to the pilot's area of interest. The pilot is able to obtain aviation-specific weather for the entire area or for his specific route. The route, altitude, true airspeed, and proposed departure time can each be modified in AWE. Integral visual display of these three elements of weather reports makes AWE a useful planning tool, as well as a weather briefing tool.
Analysis and Prediction of Weather Impacted Ground Stop Operations
When the air traffic demand is expected to exceed the available airport's capacity for a short period of time, Ground Stop (GS) operations are implemented by Federal Aviation Administration (FAA) Traffic Flow Management (TFM). The GS requires departing aircraft meeting specific criteria to remain on the ground to achieve reduced demands at the constrained destination airport until the end of the GS. This paper provides a high-level overview of the statistical distributions as well as causal factors for the GSs at the major airports in the United States. The GS's character, the weather impact on GSs, GS variations with delays, and the interaction between GSs and Ground Delay Programs (GDPs) at Newark Liberty International Airport (EWR) are investigated. The machine learning methods are used to generate classification models that map the historical airport weather forecast, schedule traffic, and other airport conditions to implemented GS/GDP operations and the models are evaluated using the cross-validations. This modeling approach produced promising results as it yielded an 85% overall classification accuracy to distinguish the implemented GS days from the normal days without GS and GDP operations and a 71% accuracy to differentiate the GS and GDP implemented days from the GDP only days.
Atmospheric attenuation calibrations of surface weather observations
A correlation between near-IR atmospheric attenuation measurements made by the Atmospheric Visibility Monitor (AVM) at the Table Mountain Facility and airport surface weather observations at Edwards Air Force Base has been performed. High correlations (over 0.93) exist between the simultaneous Edwards observed sky cover and the average AVM measured attenuations over the course of the 10 months analyzed. The statistical relationship between the data-sets allows the determination of coarse attenuation statistics from the surface observations, suggesting that such statistics may be extrapolated from any surface weather observation site, Furthermore, a superior technique for converting AVM images to attenuation values by way of MODTRAN predictions has been demonstrated.
Turnbull, D A; Bevan, J R
The damaging effects of airport de-icers to adjacent waterways have been suggested by a number of studies, but none have been able to demonstrate these effects in a field situation. The Ouseburn is a part-urban and partrural catchment of varied land-use and includes a tributary which drains the Newcastle International Airport. The tributary contributes only 3-5% of the river's average flow, yet it had a disproportionately adverse impact upon the river. This paper demonstrates how this was linked to the airport's winter application of urea salt de-icers. An integrated approach involving hydrological, chemical, bacteriological and macroinvertebrate sampling was used. During cold weather, higher levels of ammonia were recorded in the tributary and downstream, and concentrations peaked during runoff events. It is suggested that hydrolysis, facilitated by urea digesting bacteria, and surface runoff is the mechanism by which ammonia enters the stream. The airport tributary had a less diverse macroinvertebrate fauna than expected and had larger numbers of bacteria which were able to utilise urea. In-situ bioassay experiments found large deaths of Gammarus pulex (L.) and low biotic indices at a site downstream of the airport tributary confluence. Together with elevated ammonia levels this suggested that urea application adversely impacted on the main stream's water quality and ecology. The airport authorities have responded by changing to a less toxic de-icer. PMID:15091545
Weather Data Receiver
Northern Video Graphics, Inc. developed a low-cost satellite receiving system for users such as independent meteorologists, agribusiness firms, small airports or flying clubs, marine vessels and small TV stations. Called Video Fax, it is designed for use with certain satellites; the GOES (Geostationary Operational Environmental Satellite) spacecraft operated by the National Oceanic and Atmospheric Administration, the European Space Agency's Meteosat and Japan's Geostationary Meteorological Satellite. By dictum of the World Meteorological Organization, signals from satellites are available to anyone without cost so the Video Fax user can acquire signals directly from the satellite and cut out the middle man, enabling savings. Unit sells for about one-fifth the cost of the equipment used by TV stations. It consists of a two-meter antenna; a receiver; a microprocessor-controlled display computer; and a video monitor. Computer stores data from the satellites and converts it to an image which is displayed on the monitor. Weather map can be preserved as signal data on tape, or it can be stored in a video cassette as a permanent image.
Dangerous Fog Analyses and Forecast in the Maceio Airport, Brasil
Fedorova, N.; Silva, A.; Levit, V.; Santos, E.
A small airplane fatal accident has occurred near Maceio Airport, on the coastal region on 26 July 2007. Low visibility in the intensive fog has provoked this accident. Weather forecast analysis, published in the local and central Brazilian newspapers during 2007, showed fog forecast absence during whole year. A study of the fog formation causes was elaborated using the high and low resolution satellite data, radar data, different products of NCEP reanalysis data and high resolution regional MM5 model simulation. The trade winds with a weak cyclonic curvature at the low levels have generated the humidity convergence at the superficial layers up to 850hPa on the coastal region. An anticyclonic circulation existence at the middle and higher levels and weak ascendant motion (by NCEP data) have support a weak convection development. The low levels clouds development on the continental region and convection development over ocean were confirmed by the radar and satellite data. A thermal inversion near surface level (up to 150m) and descendent movement at the middle and high levels were identified by MM5 model. Fog formation was simulated by PAFOG model. The conventional airport observations have shown the minimal visibility of 200m between 4 and 7a.m. Moreover visibility less than 1000m between 1 and 8a.m. with the minimal visibility of 213m was simulated by PAFOG model.
Basalt Weathering Rates Across Scales
Navarresitchler, A.; Brantley, S.
Weathering of silicate minerals is a known sink for atmospheric CO2. An estimated 30%-35% of the consumption of CO2 from continental silicate weathering can be attributed to basalt weathering (Dessert et al., 2003). To assess basalt weathering rates we examine weathering advance rates of basalt (w, mm/yr) reported at four scales: denudation rates from basalt watersheds (tens of kilometers), rates of soil formation from soil profiles developed on basaltic parent material of known age (meters), rates of weathering rind formation on basalt clasts (centimeters), and laboratory dissolution rates (millimeters). Basalt weathering advance rates calculated for watersheds range between 0.36 and 9.8x10-3 mm/yr. The weathering advance rate for a basalt soil profile in Hawaii is 8.0x10-3 mm/yr while advance rates for clasts range from 5.6x10-6 to 2.4x10-4 mm/yr. Batch and mixed flow laboratory experiments performed at circum- neutral pH yield advance rates of 2.5x10^{-5} to 3.4x10-7 mm/yr when normalized to BET surface area. These results show increasing advance rates with both increasing scale (from laboratory to watersheds) and increasing temperature. If we assume that basalt weathers at an intrinsic rate that applies to all scales then we conclude that variations in weathering advance rates arise from variations in surface area measurement at different scales (D); therefore, basalt weathering is a fractal system. We measure a fractal dimension (dr) of basalt weathering of 2.2. For Euclidean geometries, measured surface area does not vary with the scale at which it is measured and dr equals 2. For natural surfaces, surface area is related to the scale at which it is measured. As scale increases, the minimum size of the surface irregularities that are measurable also increases. The ratio between BET and geometric normalized laboratory dissolution rates has been defined as a roughness parameter, λ, which ranges from ~10-100. We extend the definition of this roughness parameter
Niblock, J. H.; McMenemy, K.; Irwin, G. W.
This paper presents a novel measurement system that assesses the uniformity of a complete airport lighting installation. The system improves safety with regard to aircraft landing procedures by ensuring airport lighting is properly maintained and conforms to current standards and recommendations laid down by the International Civil Aviation Organisation. The measuring device consists of a CMOS vision sensor with associated lens system fitted to the interior of an aircraft. The vision system is capable of capturing sequences of airport lighting images during a normal approach to an aerodrome. These images are then post processed to determine the uniformity of the complete pattern. Airport lighting consists of elevated approach and inset runway luminaires. Each luminaire emits an intensity which is dependant on the angular displacement from the luminaire. For example, during a normal approach a given luminaire will emit its maximum intensity down to its minimum intensity as the aircraft approaches and finally passes over the luminaire. As such, it is possible to predict the intensity that each luminaire within the airport lighting pattern emits, at a given time, during a normal approach. Any luminaires emitting the same intensity can then be banded together for the uniformity analysis. Having derived the theoretical groups of similar luminaires within a standard approach, this information was applied to a sequence of airport lighting images that were recorded during an approach to Belfast International Airport. Since we are looking to determine the uniformity of the pattern, only the total pixel grey level representing each luminaire within each banded group needs to be extracted and tracked through the entire image sequence. Any luminaires which fail to meet the requirements (i.e. a threshold value depending on the performance of the other luminaires in that band) are monitored and reported to the assessor for attention. The extraction and tracking algorithms have