PRAV 239 CH 3
automated station - temperature/dew point - Altimeter (inches of mercury) - Sea Level Pressure
AUTO. 20/18. A2995. SLP134
vertical movement - balance of forces - updrafts - improper calibration - temperature changes
Altimeter Error: large and rapid changes in ________________ of air. Changes upset the ____________ (hydrostatic balance) and allows atmospheric pressure related directly to altitude. Error expected in extreme _______ of thunderstorms and in strong mountain waves. Other problems include improper _________, friction, lay, improper instrument location, and ______________ of instrument.
mercury - without - A - millibars - Q
Altimeter is reported in inches of ______ in a 4 digit group ______ a decimal point and with an "____". EX: A3012 (30.12 inches). Also reports in ______ and given 4 digits proceeded by a "Q". EX1013 (altimeter at 1013mb)
zero - air - enroute - 18,000ft - fixed value - higher - higher - lower
Altimeter set on station pressure means if its on the ground it should be ________ and it will indicate absolute altitude in the _____. Be alert to changes in altimeter settings ______. Flights above _______ in the US altimeters are set to 29.92. You could crash if sea level pressure varies along a flight path while the altimeter is set at the __________. True altitude will be ______ than that indicated when sea level pressure is ______ that the altimeter setting. True altitude will be _______ when sea level pressure is lower than setting.
standard - altitude - warm - equal - lower - higher
An altimeter error can occur if the temperatures are warmer or colder than _________. Atmospheric pressure decreases with altitude more rapid in cold air than in _____. Altimeter only ensures a correct altitude on the ground. Indicated and true altimeter will ____ each other only if temperatures are standard. If the air outside is colder, than true altitude will be ______ than indicated. Warm, true will be _______.
4% - 40ft at 1,000ft MSL - height
An example: actual temperature was 10 degrees celsius warmer, true would be _____ higher making it only ____ ft at _______ ft MSL. Error increases with _________.
hydrostatic balance - density - density altitude
Changes upset the balance of forces or the _____________. _______: lower atmospheric densities yield decreased aircraft performance. _____________: pressure altitude corrected for nonstandard temperature.
pressure area - altimeter setting - station pressure - 18,000 - ground - air
Critical pressure changes occur as it travels across a high and low __________. Variable sea level pressure is fixed by adjusting altimeter to proper _____________. Sea level pressure determined from ____________ and standard atmosphere. Altitude below _______ ft in the US, adjustment ensures altimeter will read field elevation when aircraft is on the _______ and give accurate estimates of altitude above mean sea level when in the _____.
International Civil Aviation Organization - 48 - K - PA - PH
Each reporting station is listed by its four letter ______________________ (ICAO) identities. In _____ states, the letter "___" prefixes the three letter domestic identifier. In other areas of the world, first two letters indicate region, country, or state. Alaska's is _____ and Hawaii's is ______
airport - light aircraft - 60% - 40% - large problems - atmospheric pressure
High density altitude situation, actual density at the surface is found above ________ elevation in standard atmosphere. Take off distance for a __________ (not turbocharged) would be increased by ______ and climb rate would decrease by ______ of the required at sea level. A short runway on a hot day in a high, narrow mountain valley offers ________. ___________ is an essential component of aviation weather basic.
Minimum enroute altitude - plenty of sky - look out below - contract - senses - vertical air movements
MEA: ______________. Low to High _____________; High to Low _____________. Temperature variations expand or _____ the atmosphere and raise or lower pressure levels that the altimeter ______.Vertical gusts error are caused by large and rapid changes in _____________.
hourly observation - location identifier and date and time in zulu
METAR. KTPA 122150Z.
RMK - weather - SLP134
Remarks, or ________, are included to report _________ thats significant to aircraft operations. ______ is sea level pressure of 10134
observed station pressure - altimeter - difference - closely spaced - steeper - wind
Sea level pressure is either measured or emperically measured from the __________. Don;t forget to change your _______. Pressure gradient is a ___________ in pressure over a given difference. Strong pressure gradient has _________ isobars. The closer the bars are the _________ the slide. Sudden changes over short distances causes ____.
elevation - Bermuda high - high pressure systems
Sea level pressure is station pressure connected for _________. The ___________ is the steering wheel for hurricanes entering the US. ______________ are the big reason of how and where our weather comes in
29.92 - warmer/colder - vertical gusts - 1013.25mb - heating and cooling
Specific errors: MSL differs from ________, the temperatures is _____/________ than standard, strong vertical ________. Standard atmosphere is based on a fixed pressure at ____________. Important reference because different locations vary due to _____ and ________ of the earth and movements of high and low pressure areas.
Bermuda High, Aleutian Low, Siberian High , Icelandic low, Pacific High
The Larger semi permanent pressure systems are the _______, _______, _______, ______, ________
hydrostatic balance
The balance between the downward-directed gravitational force and an upward-directed vertical pressure gradient force.
weight / area - air parcel - cancel out - horizontally
The equation for atmospheric pressure is ______________. Hydrostatic balance is where the _________ resists any change vertically because the forces acting on it ___________, but can be accelerated __________ under these circumstances.
29.92 - barometers - dense - manageable - lab - fragile - toxicity
The height of a barometer is _________. Liquids other than mercury can be used in _________, however, mercury being very _______, keeps the size of the barometer_________. Accurate measurements, but not useful outside the ______. The instrument is ______, must be kept upright, and if ruptured be concerned about _______ of the mercury.
hour - selected special weather reports - unscheduled - elements
There are 2 types of weather reports: METAR which is taken every _______, and aviation _______________________ (SPECI). The social METAR observation is an ___________ report indicating a significant change in one or more ________.
inches - millimeters - pounds - millibars - hectopascal - top - 1,000 MSL
Units of Length: _____ in Hg, ______ of Hg. Units of force per area: ______ per square (PSI), ________ (mb), and ________ (hPa). Length refers to the height of the ____ of the column of mercury above the reservoir. A mercury column would be 28.92 inches at altitude of __________ MSL.
spaced out - isopleths - equal - contours - indicated altitude - true altitude - absolute alititude
Weak pressure gradient = _________ isobars. _______ but since they _____ in air pressure they are isobars. Lines of constant height are called _______. __________= altimeter; _______ = heights MSL; _________ = height NGL (ground)
METAR - AUTO - COR - disseminated - manual station
When ______ is created by a totally automated weather observation station, the modifier _____ will follow the date/time element. _______ is used to indicate corrected METAR which replaces a previously ___________ report. No modifier indicates a __________ or manual input at an automated station.
Isobars - constant pressure
_______ are lines on the charts or lines of __________
altimeter - altitude - pressure to altitude - changing
_______ is an aneroid barometer that reads in units of _______ rather than pressure. Possible by using the standard atmosphere to make the conversion from _______ to __________. Surface pressures are always changing which means ________ the altimeter reference pressure is necessary.
contours - height gradients - pressure altitude - 29.92 - altimeter
________ are lines of constant height. _________ are gradients and are rather than pressure gradients. __________ is given pressure surface in standard atmosphere. Can determine pressure MSL by setting standard sea level pressure to ______ in HG in the aircraft ______.
trough - pressure
________ is an elongated region of relatively low ______
indicated altitude - true altitude - absolute altitude
________ is the difference between altitude measured by an altimeter. _________ is the altitude of an aircraft above mean sea level. ________ is above the ground
pressure - vibrating - randomly - absolute zero
________ is the force exerted by the ________ molecules of the gas on a given area. This arises because the molecules are moving about _________ at speeds proportional to their temperatures above __________.
station pressure - isobars - ridge - troughs
_________ can be corrected for sea level pressure. _______ are lines of equal pressure; ______ is a connection of two hights; _________ is a larger thermal low (dotted line)
high (H) - surroundings
_________ is a high pressure center, a location where the sea level pressure is high compared to its __________.
horizontal - wind - diagnosis - prediction - charts - horizontal distribution
__________ differences in pressure are related to ________. Storms and fair weather areas have distinctive pressure patterns which are important aids for weather _________ and ____________. Such pressure patterns are normally identified by inspecting ________ which show the ___________ of atmospheric pressure.
low (L) - circular
__________ is a low pressure center, a ________ area with a lower sea level pressure in the center as compared to surrounding region
pressure - vibrating - 14.7 Ib - twice
__________ is the force exerted by the __________ molecules of the gas on a given area. 1 sq in of atmosphere at sea level is equal to ________; at 18,000ft its = to 7.4Ib. At sea level the atmosphere weighs _____ as much as it does at 18,000ft
temperature and dew point - M - eight - celsius
___________ and _________ are reported in two digit format in degrees celsius, separated by a slash. EX: 18/09 (indicates surface temp and dew-point). Temperatures below celsius have an "___" to indicate minus. Also could be marked in _____ digit format showing tenths of _______
aneroid barometer - air pressure - closed vessel - horizontal distribution - wind patterns
___________ has no liquid, operates on different in __________ between the atmosphere and a ________, closed container under partial vacuum, small size, robust construction, high sampling rate. Pilots need to pay special attention to the ____________ of atmospheric pressure. Pressure differences are related to ________; storms and fair weather areas have distinct pressure patterns.
pressure gradient - isobars - weak - topographical chart - slope
___________ is a difference in pressure over a given difference. if it is strong then the ______ will be close together and opposite applies if its _______. Pressure gradient on a sea level measure chart is comparable to the height gradient on a ___________ chart; stronger the height gradient, steeper the ______.
atmospheric pressure - cross sectional - down ward - upward - atmospheric pressure.
___________ is the weight of a column of the atmosphere with a given ____________ area. Special circumstance that permits increase definition is the balance between the ___________ directed gravitational force and an _________ directed force cause by the decrease of _______________ with altitude.
mercurial barometer - mercury - barometer - baros - atmosphere
_____________ is one of the most basic devices for the measurement of pressure. We measure atmospheric pressure similar to how we measure the weight of an object on a familiar balance scale. The pressure of the atmosphere is balanced against the weight of the __________. __________ is derived from a Greek word "______" that means weight. as the weight of the _________ changes, the height of the mercury column also changes
altimeter errors - 29.92 - vertical gusts - standard atmosphere - 29.92 - daily heating and cooling - high and low pressure systems
_____________ occur when sea level pressure differed from _______ in of mercury, temperature is warmer or colder than standard temperature, and or strong ____________. They Arise because _______________ is based on fixed sea level pressure of _______. Sea level pressure constantly varies with time, due to both ________________ and _______ of the earth & movements of ______ and __________________ through an area.
surface analysis chart - earth
_____________ shows pressure as well as other meteorological conditions at the surface of ______
weather charts - constant pressure surfaces (cps) - pressure height surfaces (phs) - all points - level
_____________, used to show weather systems above earth's surface, are different than sea level pressure charts. Meteorologists find it easier to deal with heights on ____________ than ___________________. A Constant phs is a horizontal plane where altitude (MSL) is all the same at ________. A cps the pressure is the same at all points but not ______.
hydrostatic balance - pressure - mercury - 29.92 in - height
_____________: downward is gravitational force; upward caused by decrease of pressure with altitude. A mercury barometer is the most basic device used to measure _______. Pressure is balanced against the weight of the ________. At sea level in standard atmosphere, the weight of the atmosphere support a column of mercury of _______ in high. As weight changes the ______ of the mercury in the column changes.
density altitude - nonstandard temperature - high - airport
______________ is the altitude above mean sea level which at given atmospheric density occurs at standard atmosphere. Pressure altitude corrected for ______________ differences. Warmer than standard surface conditions = density altitude is ________; operation of you aircraft in a high density altitude condition is = to taking off from a higher ______ during standard conditions
sea level pressure - elevation - altitude - pressure and elevation - 1 in - 1,000ft - station temperature
______________ is the atmospheric pressure measured or estimated at an _________ equal to mean sea level (MSI). Its used by pilots to determine _________ and is used in aviation reports to depict the atmospheric pressure of a reporting location. Sea level pressure can be approximated if you know station ________ and _________. You add ____ inch for every ________ ft of station elevation. At National Weather Service Stations they also take into account _________.
surface pressure measurements - altitude - land areas - different altitudes - vertical distance - horizontal difference- unrealistically strong - sea level pressure
_______________ are useful when they are compared with nearby measurements at the same _________. Over __________, the direct comparison of station pressures are usually difficult because weather stations are at ____________. Slight difference in altitude are important because the change of pressure over a given ___________ is much greater than the change of pressure over the same ___________. If vertical difference was erroneously reported as a horizontal pressure difference, it would imply an ____________________ horizontal wind. To correct altitude differences, station pressures are extrapolated to _____________.
aneroid instrument - no liquid - vessel - not wet - partial vacuum - increase - decrease - pressure value
_______________ is frequently used outside the lab. It has no ________, operates on differences in air pressure between the atmosphere and a closed ______ (an aneroid cell). Aneroid means "_______". An aneroid is a closed container under a _____________. It is strong enough to not collapse under pressure of _________ or ___________. Its change in shape is linked mechanically to an indicator that shows ___________.
High To Low Look Out Below
a rule of thumb in this context is what?
atmospheric density - 22,000 - 1/2- 40,000 - .25
aircraft performance depends critically on _______________. An airplane at ________ MSL in standard atmosphere encounters is about _____ of atmospheric density at sea level. __________ft MSL, density decreases to approximately one _____ of sea level value, about 1/10th near 60,000 ft MSL.
reported and transmitted - aviation - routine pilots - 10
altimeter settings for airports worldwide are _______ and ________ regularly with other weather info in a standard code format. Known as an '_____________ weather report' or METAR. Is commonly available to all _______. A typical METAR contains ______ or more separate elements.
aneroid barometer - g force - digital pressure transducers - robust construction
an _____________ is a small and rugged, carried in an aircraft where it can withstand _________. Current atmospheric pressure measurements and altimeter settings are based on measurements by ____________. They are small in size, have ___________, and a high sampling rate.
deteriorates - powerplant - standard temperature - 120ft - celsius - humid air
at low atmospheric densities, aircraft performance __________. Can be handled to some extent, with special aircraft and _______ designs and by attention to aircraft operations. Pressure altitude and density altitude have some value at ___________ in standard atmosphere. Density altitude increases about ______ (above pressure altitude) for every one ________ increase in temperature above standard. Moisture can have an effect on density altitude because _______ is less dense than dry air at the same pressure and temperature.
low density - high surface temperature - airports - takeoff rolls
difficulties with flight in ______________ conditions are not restricted to extreme altitudes. Deterioration of performance for aircraft operating in lower than normal density conditions caused by __________________. This is true at _______ with elevations well above sea level. Longer than usual ____________ are required as well as climb-outs are slower at sea level.
hurricanes - winter time
extremely low sea level pressure values are found in _________. High values occur in very cold ________ high pressure areas
lengths - units of force per area - surface - 1 inch - 1000ft - inverted - atmosphere - balanced
pressure is expressed in units of _____ and units of ____________. The length refers to the height of the top of the column of mercury above the ______ of the mercury reservoir of the barometer. Pressure decreases about ____ inch of mercury per ______ft. The mercurial barometer is constructed by pouring mercury into a tube. The tube is _______ into a reservoir of mercury open to the ________. Mercury flows back out the tube until the weight of the remaining mercury column is ________ by the pressure of the atmosphere over the mercury reservoir.
highs, lows, troughs, and ridges - stratosphere - aloft
the _____, ______, ______, and the _________ are found in the sea level pressure field often extended well above the earth's surface, well into the ________. Some occasions, well-defined low and high pressure systems may only exist _______.
location, intensity, and vertical extent - flight path - altitudes - wind - temperature - weather conditions
the ______, ______, and __________ extent of atmospheric pressure systems are critical in determing weather conditions along the _________. useful to examine weather charts at various _________ to determine general _____, _____, and _________
10ft - 0.1 in - decrease - standard atmosphere - nonstandard
the barometric set knob is designed to change the altimeter indication approximately _____ ft every ____ in Hg change on scale. Increasing the altimeter setting causes indicated altitude to _________. If state of atmosphere is the same as ________ then the pressure altitude is equivalent to actual altitude. Altimeter indications in exact if actual atmospheric conditions are ____________; true even if altimeter is in perfect working condition.
constant pressure charts - elements
upper air weather charts are also called _____________. The difference between constant pressure and sea level charts is the way __________ are described.
