ESSC Quiz 2
What is weather forecasting largely determined by?
Air mass characteristics, how they will change, and how they will move
Satellites
Bodies that orbit the planet. The moon is a natural satellites. Man-made ones can be placed in different orbits with different characteristics. Weather satellites commonly have geosynchronous orbits or polar orbits. Satellites have monitors that record various types of radiation
Types of clouds in a warm front and type of rain
Cirrus, cirrostratus, altostratus, nimbostratus. A continuous rain occurs just ahead of the front
Air mass responsible for record breaking lows temperature over a large portion of North America
Continental Arctic
Air mass responsible for refreshing, cool dry breezes after a hot summer spell in central plains
Continental polar
The radar image provides a color coded image. What parameter do the color codes represent? Provide an abbreviation and the long name for the parameter.
DBZ = reflectivity
GPS
Global positioning system. Can be used in Radiosonde's to provide a more accurate position of data back to the computer for wind computations.
Common weather map contours:
Isotherms (temperature) Isobars (pressure) and Isotach (wind speed)
What type of air mass is responsible for a hot, muggy summer weather in the midwest and east
Maritime tropical
Infrared (IR) Satellite images
Measure the amount of IR radiation from the earth's surface. Infrared radiation is a measure of temperature variations. Warm areas are dark
Radar detects precipitation, but Doppler radars can detect another weather parameter. What other parameter can Doppler radars detect?
Motion/air direction
Polar satellites
Orbit at 1 revolution per 100 minutes as the earth rotates under the satellite each successive pass lies west of the previous path. (Prime meridian)
WHY do we contour?
Organize all the available data so we can make sense of it. We have all that station map data, so let's use it and be able to forecast from it.
How do winds flow on a contour map?
Parallel to the lines, and the direction they are coming from
RADAR
Radio Detection And Ranging. Are instruments that send out a radio frequency wave of energy. This wave partially reflects off objects in the atmosphere such as rain and snow.
What do contour lines tell us?
Regions of high and low pressure, fronts, temperature, wind direction and speed, how weather is going to change
850 mb map (5000 ft) upper air map
Represents the lower troposphere. Rocker mountains influence the pressure surface. Over non mountainous regions the temperatures are used because the daily temp variations are less. Use to help determine if precipitation is going to be rain or snow.
upper air maps: station model codes
Station models are also plotted on many upper air weather maps and are slightly different than surface station models.
Sea-Level Equivalent Pressure
Station pressure is read at the station. Mean sea level pressure is 1013.25 mb or 14.7 lb/in^2. Sea level pressure-station pressure adjusted down to sea level ( ~ 1 mb to 10m)
UTC Time or Zulu time to EST time
Subtract four hours
Geostationary Satellites
The geosyncronus orbit orbits the earth at 12 revolutions per dat so that it always remains over the same surface locations. It is a special geosyncronous orbit that is positioned over the equator. North america is covered by 2 satellites the GOES east and the GOES west.
Radar reflectivity and ground clutter
The larger the object and the more of them the more reflection (DBZ). Occasionally and especially at night, the radar beam bends toward the ground and you get a roundish pattern of 'ground clutter' around the radar station
On a visible image bright clouds imply that the clouds are thick or thin?
Thick
300 mb map (30000 ft)
Top of the troposphere. The level at which commercial jets fly on transcontinental flights. Records the motions of the jet stream (very fast winds). Use the isotach lines (lines of equal wind speeds) determine jet stream other wind variations that effect each other
Warm front
Warm air mass replacing a cooler air mass
Radiosonde
Weather balloons sent up twice a day to observe weather in the vertical. The data is obtained by radiosonde and are called soundings.
Occluded front
When a warm front is trapped by two cold fronts
Once contoured, what can you determine?
Wind direction, high and low pressure systems, locations of possible precipitation, fronts, regions of strong winds and changing temperatures. All from a map!
Stationary front on a weather map
With alternating red semicircles pointing away from the warm air and blue triangles pointing away from the cold air
Fronts
air are masses that are separated by zones of transition which cause changes in the weather
Continental polar air mass
air mass characterized by low temperatures and dry air. NOT AS COLD as arctic air masses
Continental arctic air mass
an air mass characterized by extremely low temperatures and very dry air
Maritime (marine) tropical air mass
an air mass characterized by high temperatures and high humidity
continental tropical air mass
an air mass characterized by high temperatures and low humidity
Maritime (marine) polar air mass
an air mass characterized by low temperatures and high humidity
Cold front on a weather map
blue line with triangles pointing in the direction the cold air is moving
How is an occluded front shown on a weather map
by a purple line with alternating triangles and semicircles pointing the direction the front is moving
Cold front
cold air mass is replacing a warmer air mass
Cold front air movement
cold dense air sinks to the ground, friction with the ground causing a bulge as it pushes the warm air up
Air mass responsible for drought with high temperature over the great plains
continental tropical
Clouds with cold front
cumulonimbus form at the front, forming fast moving thunderstorms
Longitude
distance between east and west on the earth's surface, prime meridian at greenwich england.
Latitude
distance from north to south of the earth's equator. Ranges from 0 (equator) to 90 degrees (north or south) at the poles
Visible Satellite
five geostationary satellites with visible imagers orbit the earth. Visible images show reflected sunlight for half the globe. Require sunlight thus is dark during the nighttime. Image sequence or loops allow cloud movement tracking.
Stationary front
front that stops moving or is moving very slowly
The contour lines drawn on a 500 mb chart are lines of constant
heights
On an IR image bright clouds imply that clouds are low or high topped?
high
On the 500 mb map the trough is the _______ and the ridge is the _______
high point, low point
Brighter regions on an infrared satellite image indicate what
higher colder features, high topped clouds like cumulonimbus show up bright
Air mass
large body of air whose temperature and humidity are fairly similar
Advancing warm frontal surfaces
less steep and warm air rides over cold air causing stratiform clouds and precipitation
Prime meridian
line of longitude at 0 degrees. 180 total. Divides the earth into eastern and western hemisphere. Greenwich, England.
Isobars
lines of equal pressure
Air mass responsible for daily thunderstorms over the gulf coast
maritime tropical
Rules of contouring
never cross each other, a line has values higher than the line value on one side and values lower on the other side of it. Isotherm of 10 degrees F has temps below that on one side and temps above it on the other. Only drawn where there is data. Evenly spaced increments are always used. Easiest to find a high or low value first and work from there.
Surface maps
over 10,000 land-based stations, ships, airports, and buoys provide surface weather on an hourly basis. Areas of high and low pressure and isobars are plotted. Fronts and station models also usually plotted. Winds usually blow in to and counterclockwise around lows in the northern hemispheres. Look for patterns in the data, similarities and differences to forecast weather.
Equator
perpendicular to the earth's axis of rotation. It divides earth into the Northern and Southern hemisphere.
Types of air masses on (surface maps) on N. America are
polar, tropical, maritime, and continenta;.
Weather station models (weather data)
provide much weather data are also potted on many weather maps. (Symbols)
Warm front on a weather map
red line with half circles pointing the direction the warm air is moving
Contouring data
represents a line of equal values in a map area. May not have more than one value. On a topographic map contour lines represent elevation changes.
500 mb map (18000 ft) upper air map
represents the mid-troposphere. Middle of the atmosphere, half above half below. This level is used to represent the upper level air flow it is above surface influences, but below jet stream influences. Indicates where storms are going. Winds blow parallel to the height contours
Upper air map
represents variations in the pressure surface at a given pressure (500 mb) it is reported as a height from the surface. Heights, temperatures (isotherms), winds (isotachs), and station models are plotted and it is important to identify pressure troughs and ridges. High heights (ridges) correspond to high pressure and warm temperature, winds blow parallel to contour lines
Advancing Cold frontal surface
steep due to friction and because cold air is denser they lift warm air causing convective clouds and precipitation
Brighter clouds in the visible channel are usually _______ because of the higher water content causing higher reflectivity (VISIBLE SATELLITE)
topped
Doppler Radar
use the doppler effect where objects (precipitation) moving toward or away from the radar causes a different shift in the reflected (return echo) wave
Warm front air movement
warm air naturally rises, causing a smooth slope series of clouds form ahead of the front.
