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1W051O Vol 3

Weather Journeyman

QuestionAnswer
Energy transfer term: Occurs when energy at a specific wavelength contacts an object about the same size as the wavelength of the incident radiation Scattering.
Energy transfer term: The ratio of emitted radiation from an object to the emitted radiation from a black body at the same wavelength and temperature. Emissivity.
Energy transfer term: The ratio of absorbed radiation by an object to the absorbed radiation by a black body at the same wavelength and temperature Absorptivity.
Energy transfer term: The ratio of the total amount of radiation reflected from the object to the total amount of incident radiation. Reflectivity.
Energy transfer term: The ratio of energy that passes through an object to the total amount of energy received Transmissivity
Energy transfer term: A theoretically perfect absorber and emitter of radiation Black body.
Under Wien’s Law, on what is the wavelength of the maximum irradiance of a black body dependent? Temperature
Explain Planck’s law. Planck’s law says that the amount of radiation emitted by a black body at a given wavelength is proportional to its temperature
Explain Wien’s displacement law Wien’s displacement law, which comes from Planck’s law, says the wavelength of the maximum irradiance of a black body depends on its temperature
Explain Kirchoff’s law. Kirchoff’s law says for objects in thermodynamic equilibrium, the absorption of radiant energy must be equal to the emission of radiant energy.
List the advantages of METSAT imagery. 1METSAT imagery is an observation that is more frequent than synoptic reports.2It provides data in areas lacking conventional data, such as over ocean and desert regions.3It also enhances resolution in areas that have an organized, dense synoptic network.
What METSAT function allows systems to be put in motion? Animated Looping
What is the inclination angle of the polar orbiting satellites? Polar orbiting satellites have an inclination angle of 98.7°.
Of what areas do polar orbiting satellites provide coverage? The entire earth’s surface.
Geosynchronous satellites orbit the earth at the same angular velocity as what? The rotating earth
Which satellite allows you to loop imagery to follow fronts, lows, severe weather, and many other cloud and non-cloud features? Geostationary satellites
What satellites are considered geosynchronous satellites? GOES, GMS, METEOSAT, and INSAT satellites
Indicate whether it represents visible, far infrared, near infrared, watervapor, or SSM/I imagery: Operates at a wavelength of 0.4 to 0.74 microns (μm). Visible.
Indicate whether it represents visible, far infrared, near infrared, watervapor, or SSM/I imagery: Operates at a wavelength of 0.75 to 2.0μm. Near infrared
Indicate whether it represents visible, far infrared, near infrared, watervapor, or SSM/I imagery: Passively detects emitted and reflected microwave radiation at four wavelengths SSM/I
Indicate whether it represents visible, far infrared, near infrared, watervapor, or SSM/I imagery: Operates at 6.7μ on GOES imagery and 5.7 to 7.1μm on METEOSAT imagery Water vapor
Indicate whether it represents visible, far infrared, near infrared, watervapor, or SSM/I imagery: Operates at a wavelength of 10.2 to 12.8μm Far infrared.
Indicate whether it represents visible, far infrared, near infrared, watervapor, or SSM/I imagery: The wavelength is very sensitive to lunar radiation Near infrared.
Indicate whether it represents visible, far infrared, near infrared, watervapor, or SSM/I imagery: Measures reflected sunlight Visible
Indicate whether it represents visible, far infrared, near infrared, watervapor, or SSM/I imagery: This imagery is used for identifying vorticity maximums Water vapor
Indicate whether it represents visible, far infrared, near infrared, watervapor, or SSM/I imagery: Does not depend on reflected sunlight for an image Far infrared.
Indicate whether it represents visible, far infrared, near infrared, watervapor, or SSM/I imagery: Gaps occur in the global coverage between 30N and S latitude. SSM/I
Indicate whether it represents visible, far infrared, near infrared, watervapor, or SSM/I imagery: You are seeing the reflectivity of features that are converted to brightness values Visible
Indicate whether it represents visible, far infrared, near infrared, watervapor, or SSM/I imagery: You are seeing the temperature of features that are converted to brightness values. Applies to both far and near infrared
Indicate whether it represents visible, far infrared, near infrared, watervapor, or SSM/I imagery: You are seeing the amount of moisture sensed in the vertical, which is then converted to a brightness value. Water vapor
GOES enhancement curves: Cool season, general purpose curve. EC.
GOES enhancement curves: WV imagery is also enhanced using this curve identifier. ZA.
GOES enhancement curves: Good all-purpose curve most commonly used for convective activity. MB.
GOES enhancement curves: A winter time curve used to define water currents, low stratus and coastal fog. JG.
GOES enhancement curves: Designed for cloud interpretation in colder northern latitudes in the winter CC.
Designed for west coast forecasters to enhance system cloud tops over the Pacific Ocean. HF.
On a global scale, what critical parameters does SSM/I measure? Atmospheric, oceanographic, and land parameters
What frequencies have two channels to include both horizontal and vertical polarizations? The 19.3, 37, and 85.5 gigahertz frequencies
What are the three main advantages of the SSM/I? The microwaves penetrate the clouds with little or no attenuation. The sensing is independent of solar illumination. Also, SSM/I provides information complementary to that available with visible and IR imagery
How long does it take the SSM/I sensor to complete one complete revolution of the globe? How many revolutions occur per day? 102 minutes. 14.1 revolutions per day.
What is the scan width covered by SSM/I at the earth’s surface? 1,400 kilometers.
What are the parameters that can be interpreted from SSM/I using EDRs? precip intensity of storms over land & water,cloud concentration, cloud water content,& WV over the ocean
How accurate are brightness temperatures for SDRs? Within 1Kelvin
When you interpret SDRs, what are each of the frequencies best for viewing? The 19 and 37GHz channels are most useful for viewing surface phenomena. The 22.2GHz channel is for viewing atmospheric water vapor while the 85GHz channel is for viewing rain and clouds.
What clouds are virtually invisible at microwave frequencies and why? Cirrus, because they are composed mostly of small ice crystals.
Using SSM/I, what two main features of tropical storms can we better detect? The eye of the vortex and the structure of deeply convective regions.
How are the winds reported on weather products? Earth relative
What are the four types of pure motion? Describe each. translation, rotation, divergence and deformation. Translation is straight-line movement. Rotation is the turning about a point. Divergence is the spreading or contraction of the wind field. Deformation is thestretching or shearing of the wind field
What are the two main types of motion responsible for system perspective winds? How do they appear on satellite imagery? Rotation and deformation. The signature of rotation is the vorticity comma cloud. The signature of deformation is the deformation zone cloud system.
What satellite data is the most conducive for satellite looping? Geostationary satellite data
Type of animated satellite imagery: Shows the interaction between the mid-latitude systems and tropical systems. Animated water vapor satellite imagery.
Type of animated satellite imagery: Clouds appear the same despite the time of day. Animated infrared satellite imagery.
Type of animated satellite imagery: Offers the best spatial resolution imagery and the best temporal resolution as well. Animated visible satellite imagery.
Type of animated satellite imagery: Interpretation is not straightforward. Animated water vapor satellite imagery.
Type of animated satellite imagery: Only available during daylight hours. Animated visible satellite imagery.
Type of animated satellite imagery: Low-level phenomena are sometimes difficult to detect. Animated infrared satellite imagery.
Generally, when enhancing satellite imagery, how many colors is it best to use? Can you exceed that number? If so, what are the criteria? Generally, no more than two colors. A third color can add to the utility of the enhancement if it corresponds to extreme conditions that occur over a very small geographical area or if it occurs within an area enhanced with another color
What are the satellite imagery time intervals that are useful for looping data on a planetary scale? Synoptic scale? Mesoscale? On the planetary scale: 3 or 6 hour intervals. On the synoptic scale: 2 hours is satisfactory, 1 hour is ideal. On the mesoscale: 1 hour intervals are essential.
Cyclones are located by identifying the center of a closed cyclonic circulation in the clouds. Which satellite loops are best for identifying upper-level and surface cyclones? Infrared loops are best for identifying upper-level cyclones and visible loops are best for identifying surface cyclones
Why is the exact location of the anticyclone’s circulation center difficult to place? Because anticyclones are large, broad features.
What should you look for on infrared imagery to indicate that precipitation is increasing? Rapidly expanding and cooling cloud tops are an indication precipitation will increase
What type of cloud pattern is the first indicator a short-wave trough is interacting with a frontal boundary? A slight “S” shape developing on the cold-air side of the cloud pattern
Cloud formation/appearance: Common in the tropic and subtropic regions. Cloud streets.
Cloud formation/appearance: A cloud form such as cumulus, stratus, altostratus, etc Cloud type.
Cloud formation/appearance: Low-level clouds that develop because of low-level convergence Cloud fingers.
Cloud formation/appearance: The smallest cloud seen on an image as determined by the resolution of the satellite sensor. Cloud element.
Cloud formation/appearance: A nearly continuous cloud formation where elements are connected and the line is less than 1 in width. Cloud lines.
Cloud type: These clouds look the same as a small CB cloud or TCUs on VIS imagery. Enhanced cumulus
Cloud type: These appear on VIS imagery as light gray to white with a washboard appearance Billow clouds.
Cloud type: These appear bright white with a sharp edge along the ridgeline on VIS imagery. Lee-of-the-mountain cirrus.
Cloud type: These are medium gray to dark gray showing up slightly warmer than open-cell CU on FIR imagery. Actiniform clouds.
Cloud type: On VIS imagery, these clouds appear light gray to white depending on the contamination factor. Stratocumulus lines.
Cloud type: On visual imagery, these appear as a white to light gray shade in a uniform sheet with no texture. Fog and stratus
Cloud type: On VIS imagery, these clouds appear as a bright white cloud sheet with a textured or lumpy appearance Altocumulus.
Cloud type: On VIS imagery, these clouds appear as gray shades, ranging from white in the center to medium gray to white on the edges. Closed-ellstratocumulus.
Cloud type: On WV imagery, these range from a light gray to a bright white shade, depending on how thick the cloud is and the amount of water vapor below them. Cirrus.
Cloud type: On FIR imagery, only the large concentrated areas of these clouds show up; they appear as a very dark gray shade, which represents warm temperatures Cumulus.
Cloud type: On FIR imagery, these clouds appear as a dark gray shade, which suggests warm temperatures. Their cellular or textured appearance may not be observable due to the sensor resolution. Stratocumulus.
Why does VIS imagery pick up snow and ice better than IR imagery? Because of the brightness contrasts on the imagery
Why is sun angle an important consideration when we look at snow? The brightness (reflectivity) of the snow decreases rapidly when the angle is below 45 degrees. Also it is easier to distinguish cloud cover from snow because of the shadows with a low sun angle.
How does dust appear on METSAT imagery? Dust has a filmy, diffuse appearance with a medium to light gray shade on VIS and FIR imagery. If it shows up on FIR, it is a dark to medium gray shade.
How do haze, pollution, and aerosols appear on VIS imagery? They appear dull, filmy, and diffuse with a light to medium gray shade, depending on how dense.
How do haze, pollution and aerosols appear on FIR imagery? They only appear if they are at high altitudes or in large concentrations
What causes sun glint? The sun’s rays reflecting off the water surface directly into the METSAT sensor.
How does sun glint appear on geostationary satellites? On polar orbiting satellites? pattern has a circular shape to it when we view it on a geostationary METSAT image. On polar orbiting satellites, it shows a line pattern from the top to the bottom of the picture if the satellite subpoint and the solar subpoint are sufficiently close.
What is sun glint used for? To estimate the surface wind speeds, direction, and the state of the sea and to locate flooded lowlands that can be used for Army trafficability support.
On what METSAT imagery does the terminator phenomena appear? VIS imagery
Wind field composition term: Shearing or stretching of the wind field. Deformation.
Wind field composition term: Movement of an air parcel in a straight line. Translation.
Wind field composition term: Contraction of the wind field toward a central point Convergence.
Wind field composition term: Circular wind pattern turning around a specific point Rotation.
Wind field composition term: Spreading of the wind field away from a central point. Divergence.
Wind field composition term: The center of the deformation zone where the winds are calm. Neutral point.
Wind field composition term: The horizontal axis where air parcels are moving toward the col. Axis of contraction.
Wind field composition term: The horizontal axis where air parcels are moving away from the col. Axis of dilatation.
What primarily compose surface winds around a low-pressure area? Rotation and convergence
List the steps involved in using METSAT imagery for upper tropospheric interpretation 1-Identify the cloud pattern 2-Use the cloud pattern recognition, and cloud and non-cloud phenomena, to help determine the wind flow. 3-Use the cloud patterns and wind flow to determine specific synoptic features and relate them to the map features
What is used to draw in moisture patterns when analyzing upper-air products? Cloud patterns
What are the cloud features that make up a synoptic-scale comma cloud? Baroclinic zone clouds, vorticity comma clouds, and deformation zone clouds
Which comma-cloud feature is associated with the thickness ribbon on the thickness product? Baroclinic zone clouds.
What is another name for the surge region? Dry slot
What are the two techniques we use to determine the upper-level wind flow? The first is by following specific cloud elements on an animated satellite imagery. The second is to interpret specific cloud and non-cloud phenomena to find the wind flow
Which clouds form parallel to, and on the equatorward side of the jet stream flow and needs at least 60 knots for formation? Cirrus streaks
Where is the jet stream axis located in relation to baroclinic zone cirrus? About 1 latitude on the poleward side of the sharp cloud edge
When no high clouds are present at the jet stream level, where would the axis be located? Normally 1 to 3 on the poleward side of the boundary between the open-cell CU and the closed-cell SC
Where would the jet axis be located with lee-of-the-mountain cirrus? About 1 of latitude on the poleward side of the cirrus cloud
On WV imagery, what would you look for when you try to locate the jet stream? Areas of dark (dry) and light (moist) gray shade contrast
When a 500-mb short-wave trough intersects a frontal cloud band, what happens to the cloud types and coverages? Downstream from intersection, baroclinic zone clouds are present. Upstream from intersection point, no high- and mid-level clouds are present. The low frontal clouds thin out, become fragmented, and may even disappear due to the downward vertical motion.
What METSAT imagery is the most useful in detecting upper-level deformation zones and why? WV imagery, because the deformation zone location is marked by a sharp gray shade contrast between dry and moist regions
With what cloud structures are vorticity maximums associated? Baroclinic leaves, enhanced CU, and the vorticity comma cloud associated with the synoptic-scale comma cloud.
What type of appearance do MCC systems usually have? An egg-like appearance
What trigger maintains the MCC? The convergence of the outflow boundaries (arc clouds) associated with the individual cells
What is the first and most important rule of tropical storm analysis? pattern formed by the tropical cyclone’s clouds is related to the cyclone’s intensity rather than to the amount of clouds in the pattern. The cyclone’s intensity is related to the distance the curved band is curved around the storm center
What are the different intensity ratings that the Dvorak method uses? first is the T (tropical) number. The T number describes the rate of development or dissipation of a tropical cyclone. The second indicator is the current intensity (CI) number. It describes the true intensity of the storm.
What effect do you consider when you interpret lower-level wind flow that you do not consider in upper-level wind flow analysis? The terrain’s effects on clouds.
What type of terrain offers clues in analyzing the lower troposphere? Mountains, islands, and lakes
Why is the extra tropical surface low hard to position initially? Because it’s embedded in the multilayered cloudiness (baroclinic zone clouds).
Where are low-level deformation zones commonly found? At the tail end of the comma cloud.
Why is an atlas an essential tool for evaluating low-level wind flow? Knowing the terrain in a region helps tremendously when you analyze the wind flow in the lower troposphere.
Cloud type: Straight-line or cyclonic flow associated with these clouds Open-cell cumulus.
Cloud type: You see these under very stable, high-pressure conditions with light, anticyclonic flow Ship trails.
Cloud type: Behind a strong cold front, this can spread out cyclonically and anticyclonically in the low-level deformation zone. Blowing dust.
Cloud type: The wind flow is parallel or nearly parallel, but these clouds are mainly seen in the tropical and subtropical regions. Cumulus lines/streets
Cloud type: These are seen off the eastern and southern coastlines of continents and large lakes with a parallel or nearly parallel wind flow. Stratocumulus lines.
What phenomena are caused by the wind flow interacting with an ocean island? Bow waves, plume clouds, and Karman vortice
Frontal type: Place the front along the leading edge of the cloud band. Stationary front.
Frontal type: The PFJ turns anticyclonically on the cold side of this front. Warm front.
Frontal type: This front is positioned along the back edge of the comma cloud head Cold front & Occluded front
Frontal type: Over water, along the tail end there is usually a rope cloud that shows the exact frontal position Stationary front
Extra tropical low stage: The surface low is located in the eastern portion of the deformation zone cloud. Mature stage.
Extra tropical low stage: During this stage, the surface low is usually NOT identifiable on METSAT imagery Dissipation stage
Extra tropical low stage: On infrared imagery the clouds begin to show cooler tops indicating increased upward vertical motion Initial stage.
Extra tropical low stage: The surge region begins to wrap around the upper low with the surface low translating along the back edge of the comma head Intensification stage.
Why is it easier to position high centers and ridge axes over water than land? Because of the large amount of moisture available for cloud formation.
What is the best METSAT imagery to use for low-level deformation zone analysis? Visual METSAT imagery
Why are conveyor belts used to explain a comma cloud pattern? Because they explain the simultaneous horizontal and vertical movement of an air parcel with a comma cloud.
Name the conveyor belts associated with a comma cloud The warm conveyor belt (WCB), cold conveyor belt (CCB), and dry-air conveyor belt (DACB).
In which comma cloud pattern does the PFJ separate baroclinic zone cirrus from deformation zone cirrus? Type A pattern.
With what are shear lobes normally seen? Speed maximums
With what meteorological phenomena are vorticity advection lobes normally associated? Short-wave troughs and ridges
What kind of thickness phenomenon is located downstream from a surface low? A thickness ridge.
Frontal wave stages: The surface low begins to move under the upper low Mature stage.
Frontal wave stages: WV imagery shows the dark band wrapped around the upper low Mature stage.
Frontal wave stages: The upper low and the surface low become vertically stacked Dissipation stage.
Frontal wave stages: There is a slight “S” shape to the cloud pattern on the cold airside of the widening baroclinic zone. Initial stage
Frontal wave stages: The thickness product shows weak thermal advection ahead and behind the surface low although a strong thermal gradient exists Initial stage
Frontal wave stages: A dark band curves cyclonically within the comma head depending if the comma cloud is developing into a type A or type B system Intensification stage.
Frontal wave stages: As the vorticity comma cloud is increasing, the associated upperlevel clouds wrap around the vorticity maximum, developing more deformation zone cirrus Intensification stage.
What are the ways that a baroclinic leaf can develop into a comma cloud? It can develop upstream from the baroclinic zone clouds and merge with the baroclinic zone clouds; it can develop into a comma cloud well upstream from a baroclinic zone cloud pattern; or it can develop along the cold air side of the baroclinic clouds.
Given a baroclinic low over the ocean with an initial pressure of 990mb, what central pressure would the low have with the following characteristics: the low has a well-defined hooked pattern in the cloud band with a surge region that is very apparent? 980 to 989 mb.
What central pressure would a low have if the maximum winds are found in the northern semicircle of the low center? 980 to 989 mb.
When does the deformation zone cirrus develop with a cut-off low? When the low cuts off from the cold air and the main PFJ.
If a major short-wave trough approaches the cut-off low from the west, what will the low do? The low will begin to open up and move, accelerating northeastward, and eventually losing its closed circulation pattern to become a short-wave trough.
What causes winds generally to flow up the mountain? Differential heating
During the sea/lake breeze, what type of cloud forms along and just offshore? None
What cloud type is associated with winds of 10 to 25 knots in the wake of an island? Karman vortices
Describe a cloud plume. They are long, narrow SC lines produced by the turbulent vertical motion of air forced around an island in a strong low-level wind.
What cloud patterns can the temperature difference between the air and water cause, depending on the stability of the low-level? Ship trails, upwelling fog, and stratocumulus lines.
Where does upwelling fog occur? Why? This occurs along the west coast of continents in a stable, low-level atmosphere. It is caused by air coming in contact with the cold ocean surface and condensing into water droplets.
State how and when stratocumulus lines occur. These form when cold, dry air moves off the continents in the winter over the relatively, warmer ocean where the dry air picks up moisture.
Created by: adgaston