chapter 1 Flashcards
Meteorology:
the study of the atmosphere and its phenomena
meteors
all substances that fell from the sky
meteoroids
falling objects from outside the atmosphere
hydrometeors
water and ice particles falling from clouds within the atmosphere
Meteorologist:
a scientist that uses scientific principles to explain or forecast atmospheric phenomena
Weather vs. climate: The difference between weather and climate is
a measure of time
Weather is
what conditions of the atmosphere are over a short period of time
climate is
how the atmosphere “behaves” over relatively long period of time.
The Earth’s four spheres: Everything in Earth’s system can be placed into
one of four major subsystems
land, water, living things, or air.
These four
subsystems are called
spheres.
These four subsystems are called “spheres.” Specifically, they are the
“lithosphere” (land), “hydrosphere” (water), “biosphere” (living things), and “atmosphere” (air)
The atmosphere
contains all the air in Earth’s system
Atmosphere
The atmosphere contains all the air in Earth’s system. ****It extends from
less than 1 m below the planet’s surface to more than 10,000 km above the planet’s surface
weather occurs when
When air temperature in the lower portion of this sphere changes
As air in the lower atmosphere is heated or cooled, it
moves around the planet
As air in the lower atmosphere is heated or cooled, it moves around the planet. The result can be
as simple as a breeze or as complex as a tornado
The atmosphere is made up of many layers that differ in
chemical composition and temperature
Atmosphere
Envelope of gases that surrounds the Earth
Atmosphere - Envelope of gases that surrounds the Earth. Used by life as a
reservoir of
chemical compounds used in living systems
Atmosphere - Envelope of gases that surrounds the Earth. Used by life as a
reservoir of chemical compounds used in living systems. Atmosphere has no
outer boundary, just fades into space
Dense part of atmosphere (….. of mass) lies within ………….. km of the earth which is the same thickness as
97%
30 km
continental crust
Chemical Composition Today
Nitrogen (N2)- 78%,
Oxygen (O2)-21%,
Carbon Dioxide (CO 2) - 0.03 %,
plus other miscellaneous gases (H2O for one).
water vapor is a ……………………. gas
variable
Variable and Trace Gases: Water Vapor (H2
O)
1. Water vapor is an ………… gas
invisible
clouds are
liquid water droplets and ice crystals
water vapor is a critical component of atmosphere in regards to
weawther and climate
“Latent heat”
an important source of energy that powers storms, is released during condensation of water vapor to liquid water
water vapor is a critical …………. gas
greenhouse
water vapor Concentration in the atmosphere is highly variable in regard to
both place and time
Concentration in the atmosphere is highly variable in regard to both place and time
a. Depends mostly on
temperature, with near 0% in the arctic and up to 4% in the tropics
Ozone (O3)
The vast majority (97%) is found in the stratosphere at height 24-45 km, above the layer of the atmosphere where weather occurs
importance od ozone
it is critical to maintaining life on earth. ozone absorbs harmful, high energy UV rays from the sun so that they do not reach earth’s surface
CO2
it is variable by the effect of
human activity especially in cities
CO2 is responsible for
global heating
CO2 trace gas contributing only
0.039% of the volume of the atmosphere
CO2 is an important
green house gas
carbon dioxide cycle
a. removed from atmosphere as dissolves in oceans
oceans contain 50x the amount of CO2 than the atmosphere
b. removed by plants through photosynthesis
c. enters atmosphere by evaporation from oceans, decay ad burying of plant matter, respiration and volcanic activity
the carbon cycle creates
an equlilibrium that had maintained stable levels of CO2 in the atmsphere (280 parts per million) for thousands of years
CO2 increased during the industrial revolution by ……………. due to …………………………………
40%
burning fossil fuels
clouds are composed of
liquid water droplets
aerosols
The atmosphere is also filled with numerous tiny solid or liquid suspended particles of various composition
The atmosphere is also filled with numerous tiny solid or liquid suspended particles of various composition, called aerosols
b. Examples include
dust and soil picked up by the wind, salt from sea spray, smoke from fires and ash from volcanic eruptions
Examples include dust and soil picked up by the wind, salt from sea spray, smoke from fires and ash from volcanic eruptions
c. These aerosols serve an important function as they act as
surfaces which facilitate the condensation of water droplets to form clouds
the atmosphere is divided into different layers based upon these
chaning vertical temperature profiles
show the atmospheric layers giving temperature, height and main charactaristics
Troposphere
The word troposphere derived from the Greek word tropo and it means
turbulence or mixing
The word troposphere derived from the Greek word tropo and it means
turbulence or mixing. This is the lower most layer of the atmosphere and
is known as troposphere and is the most important layer because
almost all the weather events ( e.g fog, cloud, dew, frost, hailstorm, storms, cloud-thunder, lightning etc) occur in this layer
In the troposphere Temperature decreases with increasing height at the average rate of
6.5 0C per 1000m
(1 kilometer)
Temperature decreases with increasing height at the average rate of 6.5 C per 1000m (1 kilometer), which is called as
normal lapse rate
The height of
troposphere changes from
equator towards the poles (decreases) and from one season of a year to the other season (increases during summer while decreases during winter).
The average height of the troposphere is about …………………. over the equator
16-18km over the equator
The average height of the troposphere is about 16-18km over the equator and …………………… over the poles
7-8
The upper limit of the troposphere is called as
TROPOPAUSE
Stratosphere
temperature…
begins to increase with height
the stratosphere, the temperature begins to increase with height
b. This temperature profile is due to the
presence of ozone which absorbs ultraviolet rays from the sun, heating the surrounding air
Tropopause
The transition zone between the troposphere and the stratosphere
The tropopause is not a well-defined “layer” but a transition zone
and varies in
height from location to location
there are 3 tropopause:
tropical (16-18km with a temperature of 75C)
Midlatitude tropopause (11 km and temperature is -56.5c)
polar tropopause (7-8 km and temperature is -43c)
Mesosphere
- air is extremely thin and pressure very low
- Without the presence of ozone, the temperature profile resumes its downward trend with height
- This layer is called the mesosphere and extends up to about 50 miles (80km) above earth’s surface
Mesosphere
The top of the mesosphere is the
coldest part of the atmosphere at about −130°F
Thermosphere
In the highest levels of the atmosphere, above about 50 miles, oxygen molecules absorb very high energy rays from the sun (e.g. gamma rays, cosmic rays and x-rays) heating the “air” to very high temperatures (e.g. 500° C)
Even though temperatures are very high, it would not feel “hot” because there are so few molecules to bounce against your skin
The ionosphere extends form
60 km to 2000 km altitude
The ionosphere extends form 60 km to 2000 km altitude. Because
the composition of the atmosphere changes with height
The ionosphere extends form 60 km to 2000 km altitude. Because the
composition of the atmosphere changes with height …………………..
the ion production rate also changes and this leads to the formation of several distinct ionization peaks, the “D”( 50 km to 90 km), “E” (90 km to 120 km), and “F” layers.
Different regions of the ionosphere make
long distance, point-to-point radio communications possible by reflecting the radio waves back to Earth.
Ionospheric Layers
D
E
F
D-LAYER
- The dominant ions are NO+ and O2+
- the D layer is mainly responsible for absorption of HF radio waves
- The absorption is small at night and greatest about midday
E layer
- • The dominant ions are NO+ and O2+.
- • Ionization is due to soft X-ray (1-10 nm) and far ultraviolet (UV) solar
- radiation ionization of molecular oxygen (O2 ).
- • This layer can only reflect radio waves having frequencies less than about 10 MHz.
- • At night the E layer begins to disappear because the primary source of ionization is no longer present.
- E region peaks at about 105 km
F-LAYER
- In the F region O+ ion dominates.
- Here extreme ultraviolet (UV) solar radiation ionizes atomic oxygen (O).
- The F region is the most important part o f the ionosphere in terms of HF communications
- The F layers are thickest and most reflective of radio on the side of the Earth facing the sun
*
The Aurora
spectacular display of colors and flowing patterns of light high in the atmosphere most often seen in the northern latitudes
The Aurora is a spectacular display of colors and flowing patterns of
light high in the atmosphere most often seen in the northern latitudes.
(There is also an aurora seen near the south pole, but it is not noted as
often as it the one in the north.) The aurora is caused by
particles that stream to earth from eruptions in the sun, and which are trapped by the earth’s magnetic field. Due to the high temperatures in the sun, the particles that normally make atoms cannot hold together.
What Causes Weather?
- Atmospheric Variables: In order to understand the changing weather we only need to follow a few atmospheric variables:
- a. Temperature: how hot or cold the air is
- b. Pressure: the force exerted by the air above an area (which depends on temperature differences)
- c. Wind: the horizontal movement of air (depends on pressure differences)
- d. Moisture (humidity): amount of water vapor in the air
what causes rising and sinking motion of air
- Differences in temperature from place to place results in pressure differences
- The pressure differences cause wind
- Variability and changes in wind speed and direction at the surface (bottom of the troposphere) and tropopause (top) results in vertical (rising and sinking) motion of the air
- It is the rising and sinking (up and down) motion of the air that causes “weather”
Rising motion results in the
condensation of water vapor to form:
a. Clouds: a visible mass of tiny water droplets and/or ice crystals
b. Precipitation: any form of water, either liquid or solid, that falls from clouds and reaches the ground
Sinking motion causes
clouds to dissipate and clear weather to result
