DOCSLIB.ORG

Glossary of Meteorological Terms

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

Reference Glossary of Meteorological Terms A Aerial: Of or pertaining to the air, atmosphere, or aviation. Also, same as antenna. Absolute humidity: In a system of moist air, the ratio of the Aerograph: In general, any self-recording instrument carried mass of water vapor to the total volume of the system. Usually aloft by any means to obtain meteorological data. expressed as grams per cubic meter (g/m3). Aerometeorograph: A self-recording instrument used on Absolute instrument: An instrument whose calibration can be aircraft for the simultaneous recording of atmospheric determined by means of simple physical measurements on the pressure, temperature, and humidity. instrument. Compare to secondary instrument. AFOS: Automation of Field Operations and Services. A Absolute temperature: Temperature based on an absolute scale. communication system developed in the 1970s by the National Absolute temperature scale: A temperature scale based on Weather Service which utilized minicomputers, video displays, absolute zero. See Kelvin temperature scale. and high-speed communications to replace teletype and facsimile Absolute zero: A hypothetical temperature characterized by a machines. It was replaced by AWIPS in the 1990s. complete absence of heat and defined as 0°K, -273.15°C, or Air current: Very generally, any moving stream of air. It has -459.67°F. no particular technical connotation. Absorption: The process in which incident radiation is retained Air density: The mass density of a parcel of air expressed in by a substance. A further process always results from absorption. units of mass per volume. Absorption hygrometer: A type of hygrometer which Airlight formula: See Koschmieder’s law. measures the water vapor content of the atmosphere by means Air meter: A small anemometer with flat vanes which of the absorption of vapor by a hygroscopic chemical. indicates the number of linear feet or meters of air which have Accretion: Growth of a cloud or precipitation particle by the passed the instrument during its exposure. collision and union of a frozen particle with a super-cooled Albedo: The ratio of the amount of electromagnetic radiation water drop. reflected by a body to the amount incipient upon it, commonly Accuracy: The degree of conformity of an indicated value to expressed as a percentage. The albedo is to be distinguished an accepted standard value, or ideal value. See accuracy from the reflectivity, which refers to one specific wavelength. rating, measured accuracy. Albedometer: An instrument used for the measurement of the Accuracy rating: A number of quantity defining a limit that reflecting power (the albedo) of a surface. A pyranometer errors will not exceed when a device is used under specified adapted for the measurement of radiation reflected from the operating conditions. Accuracy rating can be expressed in a earth’s surface is sometimes employed as an albedometer. number of forms, i.e. in terms of the measured variable ALERT: Automated Local Evaluation in Real Time. Flood (±1°C), percent of span (±0.5% of span), percent of upper warning program, developed by the National Weather Service range value (±0.5% of upper range value F.S.), percent of in the 1970s, that uses remote sensors in the field to transmit scale length (±0.5% of scale length), or percent of actual environmental data to a central computer in real time. output reading (±1% of actual output reading). Allard’s law: A basic equation in night visual range theory, Acid rain: Precipitation that carries to earth sulfuric and nitric relating the illuminance of a point source of light to distance acid accumulated from air pollutants. and the transmissivity of the atmosphere. Acre-foot: The volume of water required to cover one acre to ALOHA: Areal Locations of Hazardous Atmospheres. A a depth of one foot; 43,560 cubic feet. computer model used to predict how a hazardous gas cloud Actinograph: A recording actinometer. might disperse in the atmosphere after an accidental chemical Actinometer: An instrument which measures the intensity of release. Part of the CAMEO system. radiation by determining the amount of chemical change or Alter shield: A type of rain gauge shield consisting of freely fluorescence produced by that radiation. hanging, evenly spaced slats arranged circularly around the Actual pressure: The atmospheric pressure at the level of the gauge. The advantage of this shield is that the slats do not barometer. May or may not be the same as station pressure. easily accumulate snow, permitting its use on unattended Adfreezing: The process by which one object becomes gauges. See rain gauge shield. adhered to another by the binding action of ice. Altimeter: An instrument which determines the altitude of an Adiabatic process: A thermodynamic change of state in a object with respect to a fixed level. There are two general system in which there is no transfer of heat or mass across the types of altimeters: (a) the pressure altimeter, which gives an boundaries of the system. In an adiabatic process, compression approximate measure of altitude from a pressure measurement always results in warming, expansion in cooling. Compare to and an assumed standard temperature distribution; and (b) the diabatic process. radio altimeter, which deduces altitude by electronic Aeolian: Pertaining to the action or effect of the wind. techniques. Derived from the name of the Greek god of the winds, Aeolus. Altimeter setting: The value of atmospheric pressure to which Aeolian anemometer: An anemometer utilizing the principle the scale of a pressure altimeter is set so as to indicate airport that the pitch of the aeolian tones generated by air moving past elevation. The altimeter setting is included as part of an an obstacle is a function of the speed of the air. Largely a aviation weather observation. curiosity and has been put to no practical application in Anabatic wind: An upslope wind due to local surface heating. modern meteorology. Opposite of katabatic wind. NovaLynx Corporation PO Box 240 Grass Valley CA 95945 179 Phone: (530) 823-7185 Fax: (530) 823-8997 USA Toll Free: 1-800-321-3577 www.novalynx.com Reference www.novalynx.com Glossary of Meteorological Terms Analog: Pertaining to measurements or devices in which the Apparent temperature: The perceived temperature derived output varies continuously, i.e. voltage or rotation signals. from either a combination of temperature and wind (wind Compare to digital. chill) or temperature and humidity (heat index). Anemo-biagraph: A recording pressure-tube anemometer in Approximate absolute temperature scale: A temperature which the wind scale of the float manometer has been made scale with the ice point at 273° and boiling point of water at linear by the use of springs, i.e. Dines anemometer. 373°. It is intended to approximate the Kelvin temperature scale Anemoclinograph: A recording anemoclinometer. with sufficient accuracy for many sciences, notably meteorology. Anemoclinometer: General name for a type of instrument ARDC model atmosphere: See standard atmosphere. which measures the inclination of the wind to the horizontal ASCII: American Standard Code for Information Interchange. plane. See bivane. A standard code used to represent data using 8 bits (7 data bits Anemograph: A recording anemometer. and 1 parity bit) per character. Anemometer: A general term for instruments designed to ASOS: Automated Surface Observing System. A network of measure the speed or force of the wind. Italian architect Leon instrumented weather stations deployed primarily by the Battista Alberti invented the first mechanical anemometer in National Weather Service to make weather observations 1450. Derived from the Greek word “anemos,” meaning wind. without operator involvement. Aneroid: Literally “not wet”, containing no liquid. Aspiration meteorograph: An instrument, for the recording Aneroid barograph: An aneroid barometer arranged so that the of two or more meteorological parameters, in which the deflection of the aneroid capsule actuates a pen which graphs a ventilation is provided by a suction fan. record on a rotating drum. Sometimes called aneroidograph. Aspiration psychrometer: A psychrometer in which the Aneroid barometer: A barometer which measures ventilation is provided by a suction fan. atmospheric pressure using one or a series of aneroid capsules. Aspiration thermograph: A thermograph in which ventilation Also called holosteric barometer. is provided by a suction fan. Aneroid capsule: A thin metal disc partially evacuated of air Aspirator: A device attached to a meteorological instrument used to measure atmospheric pressure by measuring its to provide ventilation; usually a suction fan. expansion and contraction. Assmann psychrometer: A special form of the aspiration Aneroidogram: The record of an aneroid barograph. psychrometer, developed by German meteorologist Dr. Richard Angstrom compensation pyrheliometer: An absolute Assmann, in which the thermometric elements are well shielded instrument developed by Swedish physicist Knut Johan from radiation. Psychrometric measurements may be taken with Angstrom (1857-1910) for the measurement of direct solar the instrument in the presence of direct solar radiation. radiation. The radiation receiver station consists of two Asynchronous: Lacking a relationship to a time base or clock. identical manganin strips whose temperatures are measured by In asynchronous communications, individual data characters attached thermocouples. One of the strips is shaded, while the are sent at an arbitrary
Recommended publications
  • Fog and Low Clouds As Troublemakers During Wildfi Res

    Fog and Low Clouds As Troublemakers During Wildfi Res

    When Our Heads Are in the Clouds Sometimes water droplets do not freeze in below- Detecting fog from space Up to 60,000 ft (18,000m) freezing temperatures. This happens if they do not have Weather satellites operated by the National Oceanic The fog comes a surface (like a dust particle or an ice crystal) upon and Atmospheric Administration (NOAA) collect data on on little cat feet. which to freeze. This below-freezing liquid water becomes clouds and storms. Cirrus Commercial Jetliner “supercooled.” Then when it touches a surface whose It sits looking (36,000 ft / 11,000m) temperature is below freezing, such as a road or sidewalk, NOAA operates two different types of satellites. over harbor and city Geostationary satellites orbit at about 22,236 miles Breitling Orbiter 3 the water will freeze instantly, making a super-slick icy on silent haunches (34,000 ft / 10,400m) Cirrocumulus coating on whatever it touches. This condition is called (35,786 kilometers) above sea level at the equator. At this and then moves on. Mount Everest (29,035 ft / 8,850m) freezing fog. altitude, the satellite makes one Earth orbit per day, just Carl Sandburg Cirrostratus as Earth rotates once per day. Thus, the satellite seems to 20,000 feet (6,000 m) Cumulonimbus hover over one spot below and keeps its “birds’-eye view” of nearly half the Earth at once. Altocumulus The other type of NOAA satellites are polar satellites. Their orbits pass over, or nearly over, the North and South Clear and cloudy regions over the U.S.
  • Summer 2018 Astron 9 Week 2 FINAL

    Summer 2018 Astron 9 Week 2 FINAL

    ORDER OF MAGNITUDE PHYSICS RICHARD ANANTUA, JEFFREY FUNG AND JING LUAN WEEK 2: FUNDAMENTAL INTERACTIONS, NUCLEAR AND ATOMIC PHYSICS REVIEW OF BASICS • Units • Systems include SI and cgs • Dimensional analysis must confirm units on both sides of an equation match • BUCKINGHAM’S PI THEOREM - For a physical equation involving N variables, if there are R independent dimensions, then there are N-R independent dimensionless groups, denoted Π", …, Π%&'. UNITS REVIEW – BASE UNITS • Physical quantities may be expressed using several choices of units • Unit systems express physical quantities in terms of base units or combinations thereof Quantity SI (mks) Gaussian (cgs) Imperial Length Meter (m) Centimeter (cm) Foot (ft) Mass Kilogram (kg) Gram (g) Pound (lb) Time Second (s) Second (s) Second (s) Temperature Kelvin (K) Kelvin (K)* Farenheit (ºF) Luminous intensity Candela (cd) Candela (cd)* Amount Mole (mol) Mole (mol)* Current Ampere (A) * Sometimes not considered a base cgs unit REVIEW – DERIVED UNITS • Units may be derived from others Quantity SI cgs Momentum kg m s-1 g cm s-1 Force Newton N=kg m s-2 dyne dyn=g cm s-2 Energy Joule J=kg m2 s-2 erg=g cm2 s-2 Power Watt J=kg m2 s-3 erg/s=g cm2 s-3 Pressure Pascal Pa=kg m-1 s-2 barye Ba=g cm-1 s-2 • Some unit systems differ in which units are considered fundamental Electrostatic Units SI (mks) Gaussian cgs Charge A s (cm3 g s-2)1/2 Current A (cm3 g s-4)1/2 REVIEW – UNITS • The cgs system for electrostatics is based on the assumptions kE=1, kM =2kE/c2 • EXERCISE: Given the Gaussian cgs unit of force is g cm s-2, what is the electrostatic unit of charge? # 2 ! = ⟹ # = ! & 2 )/+ = g cm/ s1+ )/+ [&]2 REVIEW – BUCKINGHAM’S PI THEOREM • BUCKINGHAM’S PI THEOREM - For a physical equation involving N variables, if there are R independent dimensions, then there are N-R independent dimensionless groups, denoted Π", …, Π%&'.
  • Storm Wind Loads on Trees Thought by the Author to Provide the Best Means for Considering Fundamental Tree Health Care Issues Surrounding Tree Biomechanics

    Storm Wind Loads on Trees Thought by the Author to Provide the Best Means for Considering Fundamental Tree Health Care Issues Surrounding Tree Biomechanics

    TreesTreesTrees &&& StormStormStorm WindWindWind LoadsLoadsLoads by Dr. Kim D. Coder Professor of Tree Biology & Health Care Warnell School of Forestry & Natural Resources, University of Georgia MAINE WASH. MN. VT. ND. NH. MICH. MONT. MASS. NY. 3 CT. RI. OR. WS. MICH. 2 NJ. ID. 1 SD. PA. WY. IOWA OH. DL. 5 NB. MD. IL. IN. W. NV. VA . VA . UT. CO. 6 KY. KS. MO. NC. CA. TN. SC. ARK. OK. 0 GA. AZ. AL. NM. 7 MS. TX. 8 4 LA. 9 FL. 10 Coder Storm Intensity Map of composite potential risks for tree damage. This publication is an educational product designed for helping tree professionals appreciate and understand basic aspects of tree mechanical loading during storms. This educational product is a synthesis and integration of weather data and educational concepts regarding how storms wind loads impact trees. This product is for awareness building and educational development. At the time it was finished, this publication contained information regarding storm wind loads on trees thought by the author to provide the best means for considering fundamental tree health care issues surrounding tree biomechanics. The University of Georgia, the Warnell School of Forestry & Natural Resources, and the author are not responsible for any errors, omissions, misinterpretations, or misapplications from this educational product. The author assumed professional users would have some basic tree structure and mechanics background. This product was not designed, nor is suited, for homeowner use. Always seek the advice and assistance of professional tree health providers for tree care and structural assessments. This educational product is only for noncommercial, nonprofit use and may not be copied or reproduced by any means, in any format, or in any media including electronic forms, without explicit written permission of the author.
  • 3 Atmospheric Motion

    3 Atmospheric Motion

    Final PDF to printer CHAPTER 3 Atmospheric Motion MOTION OF THE EARTH’S ATMOSPHERE has a great influence on human lives by controlling climate, rainfall, weather patterns, and long-range transportation. It is driven largely by differences in insolation, with influences from other factors, including topography, land-sea interfaces, and especially rotation of the planet. These factors control motion at local scales, like between a mountain and valley, at larger scales encompassing major storm systems, and at global scales, determining the prevailing wind directions for the broader planet. All of these circulations are governed by similar physical principles, which explain wind, weather patterns, and climate. Broad-scale patterns of atmospheric circulation are shown here for the Northern Hemisphere. Examine all the components on this figure and think about what you know about each. Do you recognize some of the features and names? Two features on this figure are identified with the term “jet stream.” You may have heard this term watching the nightly weather report or from a captain on a cross-country airline flight. What is a jet stream and what effect does it have on weather and flying? Prominent labels of H and L represent areas with relatively higher and lower air pressure, respectively. What is air pressure and why do some areas have higher or lower pressure than other areas? Distinctive wind patterns, shown by white arrows, are associated with the areas of high and low pressure. The winds are flowing outward and in a clockwise direction from the high, but inward and in a counterclockwise direction from the low.
  • Climate and Atmospheric Circulation of Mars

    Climate and Atmospheric Circulation of Mars

    Climate and QuickTime™ and a YUV420 codec decompressor are needed to see this picture. Atmospheric Circulation of Mars: Introduction and Context Peter L Read Atmospheric, Oceanic & Planetary Physics, University of Oxford Motivating questions • Overview and phenomenology – Planetary parameters and ‘geography’ of Mars – Zonal mean circulations as a function of season – CO2 condensation cycle • Form and style of Martian atmospheric circulation? • Key processes affecting Martian climate? • The Martian climate and circulation in context…..comparative planetary circulation regimes? Books? • D. G. Andrews - Intro….. • J. T. Houghton - The Physics of Atmospheres (CUP) ALSO • I. N. James - Introduction to Circulating Atmospheres (CUP) • P. L. Read & S. R. Lewis - The Martian Climate Revisited (Springer-Praxis) Ground-based observations Percival Lowell Lowell Observatory (Arizona) [Image source: Wikimedia Commons] Mars from Hubble Space Telescope Mars Pathfinder (1997) Mars Exploration Rovers (2004) Orbiting spacecraft: Mars Reconnaissance Orbiter (NASA) Image credits: NASA/JPL/Caltech Mars Express orbiter (ESA) • Stereo imaging • Infrared sounding/mapping • UV/visible/radio occultation • Subsurface radar • Magnetic field and particle environment MGS/TES Atmospheric mapping From: Smith et al. (2000) J. Geophys. Res., 106, 23929 DATA ASSIMILATION Spacecraft Retrieved atmospheric parameters ( p,T,dust...) - incomplete coverage - noisy data..... Assimilation algorithm Global 3D analysis - sequential estimation - global coverage - 4Dvar .....? - continuous in time - all variables...... General Circulation Model - continuous 3D simulation - complete self-consistent Physics - all variables........ - time-dependent circulation LMD-Oxford/OU-IAA European Mars Climate model • Global numerical model of Martian atmospheric circulation (cf Met Office, NCEP, ECMWF…) • High resolution dynamics – Typically T31 (3.75o x 3.75o) – Most recently up to T170 (512 x 256) – 32 vertical levels stretched to ~120 km alt.
  • On the Definition of the Measurement Unit for Extreme Quantity Values: Some Considerations on the Case of Temperature and the Kelvin Scale

    On the Definition of the Measurement Unit for Extreme Quantity Values: Some Considerations on the Case of Temperature and the Kelvin Scale

    ON THE DEFINITION OF THE MEASUREMENT UNIT FOR EXTREME QUANTITY VALUES: SOME CONSIDERATIONS ON THE CASE OF TEMPERATURE AND THE KELVIN SCALE Franco Pavese 1 1 Torino, Italy E-mail (corresponding author): [email protected] Abstract Many quantities are attributed a range of values that can apparently extend to infinity (on one side or both sides). In this respect, the definitions of their measurement units do not place any constraint to the maximum (or minimum) value for their validity. In general, that happens because those extreme values are far from being reached on the earth, or presently in experiments. However, since the same units are used also in fields of physics, chemistry or technology where they could occur—namely in the description of the universe in one sense, and in pico-nanoscale or particle physics in another sense—the issue of extreme values (not in statistical meaning here) is not irrelevant. The question placed and discussed in this paper is whether the present kelvin scale, based on Lord Kelvin’s second definition (our currently accepted concept of temperature), applies over a full range between bounds (0, ∞) or not, and about the concept of temperature in itself in the extremes regions. The aim, however, is not to provide an answer, but to suggest there are difficulties with the application of current concepts at extremes of temperature. Keywords: kelvin scale; Lord Kelvin proposals; extreme temperatures; temperature definition; unit definition 1 Introduction Many quantities have a range of values that can apparently extend to infinity (on one side or both sides). In this respect, the definition of their measurement units does not place any constraint to the maximum (or minimum) value for its validity.
  • The Third Law of Thermodynamics Or an Absolute Definition for Entropy. Part

    The Third Law of Thermodynamics Or an Absolute Definition for Entropy. Part

    The third law of thermodynamics or an absolute definition for Entropy. Part 1 : the origin and applications in thermodynamics. Accepted for the revue: “La Météorologie ” / Revision 2 - December 2, 2019. by Pascal Marquet. Météo-France, CNRM/GMAP, Toulouse. Abstract This article describes the third law of thermodynamics. This law is often poorly known and is often decried, or even considered optional and irrelevant to describe weather and climate phenomena. This, however, is inaccurate and contrary to scientific facts. A rather exhaustive historical study is proposed here in order to better understand, in another article to come, why the third principle can be interesting for the atmosphere sciences. 1 Introduction Before being able to study in a second part the properties of entropy in the atmosphere, it is necessary to recall in this first part why its calculation poses certain problems in thermodynamics, problems whose solution passes through the invention and the application of the third law of thermodynamics which introduces a kind of absolute in the calculation of entropy. And the idea that certain absolutes may exist had preceded the establishment of the third law. 2 The notion of absolute temperature Thermodynamics teaches us that the notion of temperature corresponds to the measurement of the energy of the microscopic agitations of atoms or molecules in the solids, liquids or gases which constitute the environment which surrounds us, and therefore in particular in the atmosphere. Carnot (1824) was able to establish the existence of universal things, supposing that the perpetual motion of thermal machines was impossible. He first highlighted the existence of a maximum efficiency that depends only on the temperatures of the bodies between which these machines operate.
  • Pressure Perturbations and Upslope Flow Over a Heated, Isolated Mountain

    Pressure Perturbations and Upslope Flow Over a Heated, Isolated Mountain

    4272 MONTHLY WEATHER REVIEW VOLUME 136 Pressure Perturbations and Upslope Flow over a Heated, Isolated Mountain BART GEERTS,QUN MIAO, AND J. CORY DEMKO University of Wyoming, Laramie, Wyoming (Manuscript received 29 January 2008, in final form 14 April 2008) ABSTRACT Surface and upper-air data, collected as part of the Cumulus Photogrammetric, In Situ, and Doppler Observations (CuPIDO) experiment during the 2006 monsoon season around the Santa Catalina Mountains in southeast Arizona, are used to study the diurnal variation of the mountain-scale surface convergence and its thermal forcing. The thermal forcing is examined in terms of a horizontal pressure gradient force, which is derived assuming hydrostatic balance. The mountain is ϳ30 km in diameter, ϳ2 km high, and relatively isolated. The environment is characterized by weak winds, a deep convective boundary layer in the after- noon, and sufficient low-level moisture for orographic cumulus convection on most days. The katabatic, divergent surface flow at night and anabatic, convergent flow during the day are in phase with the diurnal variation of the horizontal pressure gradient force, which points toward the mountain during the day and away from the mountain at night. The daytime pressure deficit over the mountain of 0.5–1.0 mb is hydrostatically consistent with the observed 1–2-K virtual potential temperature excess over the mountain. The interplay between surface convergence and orographic thunderstorms is examined, and the consequence of deep convection (outflow spreading) is more apparent than its possible trigger (en- hanced convergence). 1. Introduction mountain-scale convergence in the CBL and, under suitable stability and cumulus development, but small Significant research has been conducted on flow and enough that the solenoidal flow response to elevated pressure variations around an isolated mountain in heating is quasi-instantaneous.
  • UBO & MPD Glossary

    UBO & MPD Glossary

    UBO & MPD Glossary December 2011 Aniline Point – The aromatics content of a hydrocarbon A. mixture. Abnormal Pressure - Reservoir pore fluid pressure that Annulus Friction Pressure (AFP) – Difference is not similar to normal saltwater gradient pressure. The between bottomhole pressure and choke pressure due to term is usually associated with higher than normal friction; a function of flow rate, hole geometry, surface pressure, increased complexity for the well designer and roughness, fluid properties. an increased risk of well control problems. Abnormal – American Petroleum Institute. pressure gradients exceed a 10-ppg equivalent fluid API density (0.52 psi per foot). Gradients below normal are API Gravity - arbitrary measurement of density adopted in called subnormal. 1921 by the American Petroleum Institute and the Bureau Absolute Pressure - pressure measured with respect to of Standards. zero pressure; the sum of atmospheric pressure and gauge Apparent Power - combination of real and reactive pressure. power. Absolute Temperature - temperature measured with Apparent Viscosity - Slope of the shear stress versus respect to absolute zero, in degrees Rankine or degrees velocity gradient for a fluid. For Newtonian fluids, the Kelvin. apparent viscosity equals the absolute viscosity. Absolute Viscosity - dynamic relationship between a Aromatics – Ring group chemical structure. Most force and the fluid motion. common are benzene, toluene, and xylene. Absolute Zero Temperature - temperature that B. prevents molecular motion. Back Pressure Valve - A flow control valve to provide - rate of change in velocity. Acceleration backflow control when running or pulling a string. Active data - continually updated data, based on latest Backup – Redundant equipment available to complete an operational data. operation in the event the primary equipment fails.
  • Imet-4 Radiosonde 403 Mhz GPS Synoptic

    Imet-4 Radiosonde 403 Mhz GPS Synoptic

    iMet-4 Radiosonde 403 MHz GPS Synoptic Technical Data Sheet Temperature and Humidity Radiosonde Data Transmission The iMet-4 measures air temperature with a The iMet-4 radiosonde can transmit to an small glass bead thermistor. Its small size effective range of over 250 km*. minimizes effects caused by long and short- wave radiation and ensures fast response times. A 6 kHz peak-to-peak FM transmission maximizes efficiency and makes more channels The humidity sensor is a thin-film capacitive available for operational use. Seven frequency polymer that responds directly to relative selections are pre-programmed - with custom humidity. The sensor incorporates a temperature programming available. sensor to minimize errors caused by solar heating. Calibration Pressure and Height The iMet-4’s temperature and humidity sensors are calibrated using NIST traceable references to As recommended by GRUAN3, the iMet-4 is yield the highest data quality. equipped with a pressure sensor to calculate height at lower levels in the atmosphere. Once Benefits the radiosonde reaches the optimal height, pressure is derived using GPS altitude combined • Superior PTU performance with temperature and humidity data. • Lightweight, compact design • No assembly or recalibration required The pressure sensor facilitates the use of the • GRUAN3 qualified (pending) sonde in field campaigns where a calibrated • Status LED indicates transmit frequency barometer is not available to establish an selection and 3-D GPS solution accurate ground observation for GPS-derived • Simple one-button user interface pressure. For synoptic use, the sensor is bias adjusted at ground level. Winds Data from the radiosonde's GPS receiver is used to calculate wind speed and direction.
  • Aviation Glossary

    Aviation Glossary

    AVIATION GLOSSARY 100-hour inspection – A complete inspection of an aircraft operated for hire required after every 100 hours of operation. It is identical to an annual inspection but may be performed by any certified Airframe and Powerplant mechanic. Absolute altitude – The vertical distance of an aircraft above the terrain. AD - See Airworthiness Directive. ADC – See Air Data Computer. ADF - See Automatic Direction Finder. Adverse yaw - A flight condition in which the nose of an aircraft tends to turn away from the intended direction of turn. Aeronautical Information Manual (AIM) – A primary FAA publication whose purpose is to instruct airmen about operating in the National Airspace System of the U.S. A/FD – See Airport/Facility Directory. AHRS – See Attitude Heading Reference System. Ailerons – A primary flight control surface mounted on the trailing edge of an airplane wing, near the tip. AIM – See Aeronautical Information Manual. Air data computer (ADC) – The system that receives and processes pitot pressure, static pressure, and temperature to present precise information in the cockpit such as altitude, indicated airspeed, true airspeed, vertical speed, wind direction and velocity, and air temperature. Airfoil – Any surface designed to obtain a useful reaction, or lift, from air passing over it. Airmen’s Meteorological Information (AIRMET) - Issued to advise pilots of significant weather, but describes conditions with lower intensities than SIGMETs. AIRMET – See Airmen’s Meteorological Information. Airport/Facility Directory (A/FD) – An FAA publication containing information on all airports, seaplane bases and heliports open to the public as well as communications data, navigational facilities and some procedures and special notices.
  • What Are We Doing with (Or To) the F-Scale?

    What Are We Doing with (Or To) the F-Scale?

    5.6 What Are We Doing with (or to) the F-Scale? Daniel McCarthy, Joseph Schaefer and Roger Edwards NOAA/NWS Storm Prediction Center Norman, OK 1. Introduction Dr. T. Theodore Fujita developed the F- Scale, or Fujita Scale, in 1971 to provide a way to compare mesoscale windstorms by estimating the wind speed in hurricanes or tornadoes through an evaluation of the observed damage (Fujita 1971). Fujita grouped wind damage into six categories of increasing devastation (F0 through F5). Then for each damage class, he estimated the wind speed range capable of causing the damage. When deriving the scale, Fujita cunningly bridged the speeds between the Beaufort Scale (Huler 2005) used to estimate wind speeds through hurricane intensity and the Mach scale for near sonic speed winds. Fujita developed the following equation to estimate the wind speed associated with the damage produced by a tornado: Figure 1: Fujita's plot of how the F-Scale V = 14.1(F+2)3/2 connects with the Beaufort Scale and Mach number. From Fujita’s SMRP No. 91, 1971. where V is the speed in miles per hour, and F is the F-category of the damage. This Amazingly, the University of Oklahoma equation led to the graph devised by Fujita Doppler-On-Wheels measured up to 318 in Figure 1. mph flow some tens of meters above the ground in this tornado (Burgess et. al, 2002). Fujita and his staff used this scale to map out and analyze 148 tornadoes in the Super 2. Early Applications Tornado Outbreak of 3-4 April 1974.