Meteorology Test 1

Front 1

Distinguish between weather and climate.

Back 1

Weather is the state of the atmosphere at a particular place and time. Variables used to describe weather include: temperature, humidity, and cloudiness. Climate describes the weather in an area averaged over a period of time. Weather describes daily atmospheric conditions while climate looks at longer periods of time and utilizes seasonal averages of rainfall, snowfall, and temperature.

Front 2

What is the advantage of describing the climate of locality in terms of both average weather plus extremes in weather?

Back 2

It is particularly useful to farmers. They benefit from not only knowing the average rainfall or temperature for a location but also how often extreme weather occurs in that area.

Front 3

Identify the various sources of weather information that are available to the public.

Back 3

The public may obtain weather reports, maps, and forecasts via NOAA Weather Radio, local television or radio, The Weather Channel or other cable-TV weather reports, newspapers, and the internet.

Front 4

Describe the type of weather that usually accompanies a high (anticyclone) and a low (cyclone) in middle latitudes.

Back 4

Fair weather usually but not always accompanies a high (anticyclone) whereas cloudiness and rain or snow usually but not always accompany a low (cyclone).

Front 5

What is an air mass? What governs the temperature and humidity of an air mass?

Back 5

An air mass is a huge volume of air with uniform temperature and humidity properties that are often indicative of where it was formed. For example, an air mass that develops over a warm ocean surface becomes warm and humid.

Front 6

Explain why clouds and precipitation are often associated with fronts?

Back 6

Fronts are transition zones between two air masses. The property difference and air movements between the air masses give rise to cloudiness and precipitation.

Front 7

Distinguish between GOES and POES weather satellites.

Back 7

GOES orbits the Earth at a very high altitude but at the same rate as the planet rotates on its axis, so that the satellite is always positioned above the same spot on Earth's surface (the subsatellite point) and its sensors always observe the same portion of the planet. POES is much closer to the surface but orbits the Earth in a north-south direction passing near the poles. The satellite's orbit traces out a plane in space while the planet rotates underneath. A sunsynchronous polar-orbiting satellite scans the same area twice a day.

Front 8

What advantages does an infrared satellite image offer over a visible satellite image for monitoring the state of the atmosphere?

Back 8

Infrared satellite sensors detect infrared radiation that is continually emitted to space by the Earth-atmosphere system. Hence, infrared images can be obtained 24 hours a day. Visible satellite sensors detect sunlight reflected by the Earth-atmosphere system. Hence, visible images are possible only during daylight hours.

Front 9

Describe how weather radar detects the location and movement of areas of precipitation.

Back 9

Operating in the reflectivity mode, weather radar locates and tracks the movement of areas of precipitation. Based on the intensity of the reflected signal (echo), weather radar distinguishes the intensity of precipitation. Operating in the velocity (Doppler) mode, weather radar can determine the circulation within thunderstorms and provide early warning of the development of severe weather.

Front 10

What causes high thin cirrus clouds to appear fibrous or wispy?

Back 10

High thin clouds (e.g., cirrus) are composed of tiny ice crystals that give those clouds a fibrous or wispy appearance.

Front 11

What is thought to be the principle source of water on Earth?

Back 11

The ocean is the immediate source of water on Earth. Earth was once a dry rocky mass, but now its surface is 71% water. The source of this water is believed to be from asteroids and meteorites that impacted Earth.

Front 12

The chief source of Earth's early atmosphere was outgassing. Explain what is meant by outgassing. Does outgassing still operate today?

Back 12

Outgassing refers to the release of gases (e.g., water vapor, nitrogen) to the atmosphere that accompanies a volcanic eruption or meteor impact on Earth's surface. Outgassing was one of the major processes involved in the evolution of Earth's atmosphere. While outgassing occurred at a rapid pace within a million years of the planet's formation, a small amount of outgassing still takes place today.

Front 13

Explain how living organisms played an important role in the evolution of Earth's atmosphere.

Back 13

Living organisms played a large role in Earth's atmosphere, primarily through photosynthesis. Oxygen is a byproduct of photosynthesis and became abundant in the atmosphere about 2.3 billion years ago.

Front 14

Distinguish between the homosphere and the heterosphere.

Back 14

The homosphere is the area of the atmosphere below 80 km in which the principal gases are well mixed and in almost the same relative same proportions. Above 80 km lies the heterosphere where the concentrations of heavier gases decrease more rapidly with altitude than do the concentrations of the lighter gases.

Front 15

The significance of an atmospheric gas or aerosol is not necessarily related to its amount or concentration. Explain this statement and provide a few examples.

Back 15

The principal gases in the homosphere are nitrogen and oxygen and are significant and essential, however other gases and aerosols in small quantities are significant constituents. Water vapor, carbon dioxide, and ozone are minor components of the atmosphere. Water vapor is an essential component of the water cycle and the major greenhouse gas in the atmosphere. Carbon dioxide is necessary for photosynthesis. Ozone formation and dissociation in the stratosphere shields living organisms on Earth's surface from exposure to potentially lethal levels of solar ultraviolet radiation.

Front 16

Distinguis among the various types of scientific models used in meteorology and climatology.

Back 16

Atmospheric scientists use physical models to create small scale replications of a system, graphical models to represent the state of the atmosphere at a specific time and geographical area, conceptual models to portray the interaction of atmospheric variables such as wind, temperature and pressure, and numerical models that use mathematical equations describing the Earth-atmosphere system to forecast the weather and climate.

Front 17

What are the components of ASOS and where is the observational data initially sent?

Back 17

The Automated Surface Observing System (ASOS) consists of electronic sensors for measurements, computers, and automated communication ports. ASOS directly feeds data to NWS communications networks 24 hours a day to Forecast Offices and airport control towers.

Front 18

What is the principal mission of the National Weather Service Cooperative Observer Network?

Back 18

The NWS Cooperative Observer Network is made up of approximately 8,700 volunteers that monitor NWS provided instruments and take daily observations. Their mission is to record data for climatic, hydrologic, and agricultural purposes.

Front 19

What is a radiosonde? Describe the function served by a radiosonde launch.

Back 19

A radiosonde provides vertical profiles (soundings) of temperature, pressure, and dewpoint (a measure of humidity) up to a maximum altitude of about 30,000 m (100,000 ft.). Data are radioed immediately to a ground station and no recovery of an instrument is required. Tracking the instrument's horizontal movements gives a vertical profile of the horizontal wind speed and direction (rawinsonde observation).

Front 20

Compare the properties of the troposphere with those of the stratosphere.

Back 20

Most cloud and weather systems are confined to the troposphere and within the troposphere the temperature generally decreases with increasing altitude. Few clouds and little weather occur in the stratosphere. Within the stratosphere the mean temperature is either steady or increases with altitude. Also, the ozone shield occurs within the stratosphere. The tropopause is the transition zone or boundary between the troposphere and the stratosphere.

Front 21

What is the basis for subdividing the electromagnetic spectrum into various forms of electromagnetic radiation?

Back 21

The electromagnetic spectrum is subdivided because we detect, measure, generate, and use the forms differently. They have varying wavelengths, frequencies, and are used for different purposes, including medical and communications.

Front 22

What is a blackbody? Is the Earth-atmosphere system a blackbody?

Back 22

A blackbody is a perfect radiator, that is, it absorbs all incident radiation at all wavelengths and emits all radiation at all wavelengths. No radiation is reflected or transmitted. Blackbody does not refer to the color of the radiation object. The Earth-atmosphere system is not a blackbody.

Front 23

Apply Wien's displacement law in comparing the radiational properties of the Sun versus those of the Earth-atmosphere system.

Back 23

Wien's displacement law states that with increasing absolute temperature, the wavelength of the maximum radiation emitted or absorbed will decrease. Therefore, hot objects such as the Sun emit radiation that peaks at shorter wavelengths than relatively cool objects such as Earth.

Front 24

How does solar altitude affect the length of the path of solar radiation through Earth's atmosphere?

Back 24

With increasing solar beam's path length through the atmosphere decreases, reducing the attenuation of incoming solar radiation by reflection, scattering, and absorption.

Front 25

In the Northern Hemisphere, Earth is closer to the Sun during the winter than during the summer and yet winter is colder than summer. Please explain.

Back 25

Winters are colder than summers because maximum solar altitudes are lower (less intense solar radiation striking Earth's surface) and daylight is shorter in winter than in summer.

Front 26

What is the significance of the Tropic of Cancer and the Tropic of Capricorn relative incident solar radiation.

Back 26

At 23.5 degrees N and S latitude respectively, the Tropics of Cancer and Capricorn mark the poleward boundaries of the zone of the Earth where, at certain times during the year, the noon Sun reaches an altitude of 90 degrees (directly overhead).

Front 27

Describe the interactions of incoming solar radiation with the components of the atmosphere.

Back 27

These interactions consist of scattering, reflection, and absorption. In the process of scattering, a particle disperses solar radiation in all directions, up, down, and sideways. Reflection is a special case of scattering, where some of the solar radiation striking an interface between two different media is backscattered. During absorption some of the radiation striking the surface of an object is converted to heat energy.

Front 28

Why does the Antarctic ozone hole appear int he Southern Hemisphere spring?

Back 28

During the winter months in the Southern Hemisphere, polar stratospheric clouds form. These clouds contain water particles that allow chlorine and bromine compounds to form and cause ozone depletion. During the spring months, the Sun's radiation supplies the energy causing the polar stratospheric clouds to vaporize and the stratospheric ozone concentration returns to normal levels.

Front 29

All other factors being the same, how does cloud cover affect the day's minimum air temperature?

Back 29

The day's minimum temperature is typically higher with cloud cover than when the sky is clear. Water droplets and/or ice crystals composing clouds strongly absorb infrared radiation emitted by Earth's surface. Clouds then radiate some of the absorbed radiation as IR to space and some back to Earth's surface, thus raising the minimum air temperature.

Front 30

Provide a convincing argument that water vapor is the principle greenhouse gas.

Back 30

Water vapor is the principle greenhouse gas because it causes the greatest amount of warming at Earth's surface. For example, in the areas with very little water vapor in the air, infrared radiation readily escapes to space, causing lowered temperatures than would otherwise occur at Earth's surface. In the areas with a great amount of cloud cover or high tropospheric water vapor content, water vapor strongly absorbs infrared radiation emitted by Earth and emits some IR back to Earth's surface, having the effect of warming Earth's surface.

Front 31

Describe the relationship between the kinetic energy of the atoms or molecules composing a substance and the temperature of that substance.

Back 31

Temperature is directly proportional to the average kinetic energy of the atoms or molecules composing a substance. Therefore, as the average kinetic energy of a substance increases, so does its temperature.

Front 32

The Kelvin scale has no negative values. Explain why.

Back 32

The Kelvin scale is the best representation of the average kinetic molecular energy. When a substance has a temperature of 0 K it is at "absolute 0" and essentially has no kinetic energy because all molecular motion has ceased. A substance cannot have negative kinetic energy.

Front 33

What is meant by the response time of a thermometer? What type of thermometer has the fastest response time?

Back 33

Response time refers to the rapidity at which an instrument resolves changes in temperature. Electrical resistance thermometers have a rapid response time while bimetallic thermometers typically have the slowest.

Front 34

Explain how heat transfer follows the 2nd law of thermodynamics.

Back 34

Heat transfer follows the 2nd law of thermodynamics by flowing from where the temperature is higher to where it is lower.

Front 35

Distinguish between sensible heating and latent heating of the atmosphere. Which is more important on a global annual average basis?

Back 35

Latent heating refers to the transport of heat energy through phase changes of water. Heat is absorbed from the environment when ice melts, liquid water evaporates, or snow sublimates (vaporizes). Heat is released to the environment when water freezes, water vapor condenses, or water vapor deposits ice. Sensible heating includes both conduction and convection. On a global average annual basis, latent heating is more important than sensible heating.

Front 36

During which phase changes of water is latent heat released to the environment?

Back 36

Latent heat is released during freezing, condensation, and deposition.

Front 37

On a global annual average basis, what is the most important process in cooling Earth's surface?

Back 37

Latent heat transfer associated with evaporation is the most important cooling process at Earth's surface on a global annual average. It is more important than radiational cooling and sensible heat transfer.

Front 38

Explain how thunderstorms transfer heat from Earth's surface to the middle and upper troposphere.

Back 38

During a thunderstorm, sensible heating combines with latent heating to channel heat from Earth's surface into the troposphere. Convection currents surge to great altitudes to form cumulonimbus clouds.

Front 39

Identify the mechanisms involved in poleward heat transport within the Earth-atmosphere system.

Back 39

The 3 mechanisms involved with poleward heat transport are air mass exchange, storm systems, and ocean currents.

Front 40

Provide some examples of how Earth's surface properties influence air temperature in the lower troposphere.

Back 40

Properties on Earth's surface that influence air temperature are snow cover and moisture. Snow has a relatively high albedo and reduces the amount of solar radiation that is absorbed. Dry soil has less moisture for vaporization and more of the available heat is channeled into raising the air temperature through convection and conduction.