Term
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Definition
Water vapor is the gas phase:
Water is the liquid phase:
Ice is the solid phase: |
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Term
| Water vapor is the gas phase |
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Definition
Each molecule moves independently
– Compressible gas |
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Term
| Water is the liquid phase: |
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Definition
Water reaches it’s greatest density at 4 oC (39o F)
– Density decreases below this temperature |
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Term
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Definition
Ice is the solid phase:
– Solid ice less dense than liquid water (ice floats) |
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Term
For phase changes, heat energy must be added or
released: |
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Definition
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Term
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Definition
direct change of water vapor to ice or ice
to water vapor |
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Term
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Definition
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Term
How many calories are
required to transform 1 g
of ice at 0oC to 1 g of
water vapor at 100oC ? |
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Definition
| 80 + 100 + 540 = 720 calories |
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
= Mass of water
vapor (in grams) per mass of air (in
kilograms) at a given temperature: |
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Term
|
Definition
Grams of water vapor/
Kg of air |
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Term
How is maximum specific
humidity related to
temperature? |
|
Definition
Maximum specific humidity
increases with temperature.
Warmer air can hold more
water vapor. |
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Term
|
Definition
Mass of water vapor per mass of dry
air at a given atmospheric pressure
expressed as grams per kilogram |
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Term
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Definition
| Higher mixing ratio (more humid) |
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Term
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Definition
| lower mixing ration (dryer) |
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Term
Relative Humidity (RH) expressed in
percent = |
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Definition
Mass of Water in Air
Mass Of Water Air Can Hold |
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Term
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Definition
| greater max water vapor possible |
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Term
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Definition
| lesser max water vapor possible |
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Term
Relative humidity
decreases at |
|
Definition
higher
temperatures; increases
at lower temperatures |
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Term
|
Definition
Temperature at Which Water Vapor
Begins to Condense |
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Term
What is the primary
factor that dictates the
temperature at which
condensation occurs? |
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Definition
Humidity; Lower
humidity requires
lower temperatures
for condensation to
occur. |
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Term
|
Definition
Tdb,
can be measured using a
normal thermometer freely
exposed to the air |
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Term
|
Definition
Twb, is indicated by a
moistened thermometer
bulb exposed to air flow |
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Term
|
Definition
The Amount of Pressure Exerted
By Water Vapor in the Atmosphere |
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Term
| As more water vapor enters the atmosphere... |
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Definition
the amount of
pressure exerted by that water vapor increases. |
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Term
When the
vapor pressure maximum is reached, |
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Definition
no more water can
enter the atmosphere and the atmosphere is saturated. |
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Term
The higher the
temperature |
|
Definition
the
greater the
saturation vapor
pressure |
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Term
| Differences in temperature create changes in |
|
Definition
| density within an air parcel: |
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Term
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Definition
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Term
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Definition
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Term
| Two opposing forces work on a parcel of air: |
|
Definition
Upward buoyancy force
– Downward gravitational force |
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Term
| A parcel of lower density air will |
|
Definition
rise (more
buoyant) while denser air will descend (less
buoyant) |
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Term
|
Definition
The warming and cooling rates for a
parcel of expanding or compressing air
are termed adiabatic: |
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Term
The warming and cooling rates for a
parcel of expanding or compressing air
are termed adiabatic: |
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Definition
– Ascending air parcel cools by expansion in
response to reduced pressure at higher
altitudes
– Descending air heats by compression due to
increasing pressure at lower altitudes |
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Term
|
Definition
the rate at
which “dry” air cools by expansion or
heats by compression |
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Term
| Moist adiabatic rate (MAR) |
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Definition
is the
average rate at which ascending air that
is moist (saturated) cools by expansion: |
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Term
Moist adiabatic rate (MAR) is the
average rate at which ascending air that
is moist (saturated) cools by expansion: |
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Definition
– Latent heat of condensation in moist air is
liberated as sensible heat, reducing the
adiabatic rate of cooling
– MAR less than DAR |
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Term
|
Definition
– 10 C°/1000 m
– 5.5 F°/1000 ft |
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Term
|
Definition
6 C°/1000 m
– 3.3 F°/1000 ft |
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Term
|
Definition
Average drop in
temperature with increasing altitude (6.4
Co per 1000 m) for still, calm air |
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Term
| Environmental lapse rate: |
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Definition
Actual lapse
rate for air at a particular place and time:
– Can be lower or higher than the normal lapse
rate depending on conditions |
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Term
|
Definition
– Rising air parcel has a lower adiabatic rate
than the environmental lapse rate of the
surrounding air
– Air parcel always warmer than surrounding
environment
– Parcel continues to rise, leading to saturation
and cloud formation |
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Term
|
Definition
– Environmental lapse rate less than both the
DAR and MAR
– Both moist and dry air parcels have adiabatic
rates higher than the environmental lapse rate
– Both parcels remain cooler than surrounding
environment
– Air parcels are thus forced to settle back to
original positions |
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Term
|
Definition
is an aggregation (grouping) of
moisture droplets and ice crystals suspended in
air: |
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Term
cloud is an aggregation (grouping) of
moisture droplets and ice crystals suspended in
air |
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Definition
– Rising air parcel cools to dew point
– Further lifting causes active condensation of water
vapor around condensation nuclei (dust, soot, ash,
etc.)
– Cloud initially composed of microscopic moisture
droplets
– A million or more moisture droplets aggregate to
form a rain drop |
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Term
|
Definition
Stratiform
Cumuliform
Cirroform |
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Term
|
Definition
Develop horizontally as flat
and layered clouds |
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Term
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Definition
| Puffy and globular clouds |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| 2,000 – 6,000 m (preface alto-) |
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Term
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Definition
Above 6,000 m
Vertically developed |
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Term
|
Definition
cirrocumulus
cirro stratus
cirrus |
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Term
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Definition
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Term
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Definition
cumulus
cumunlonimbus
nimbostratus
stratocumulus
stratus
fog |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| – Showers typically fall as drizzling rain |
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Term
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Definition
Low-level puffy clouds
– Composed of water droplets
– Associated with fair weather |
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Term
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Definition
– Lumpy, grayish, low-level clouds
– Sometimes indicate clearing weather |
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Term
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Definition
Middle-level clouds
– Appear in patchy rows or wave patterns |
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Term
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Definition
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Term
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Definition
a cloud layer on the ground that
restricts visibility to less than 1 km |
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Term
|
Definition
Advection fog
Evaporation fog
Upslope fog
Valley fog
Radiation fog |
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Term
|
Definition
Advection fog forms when air in one
place migrates to another place where
conditions cause saturation |
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Term
|
Definition
Evaporation fog forms when water
molecules evaporate from the water
surface into cold, overlying air |
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Term
|
Definition
A type of advection fog where moist air is
forced to higher elevations along a hill or
mountain |
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Term
|
Definition
| Cool, dense air settles in low-lying areas |
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Term
|
Definition
Radiation fog forms when radiative
cooling of a surface chills the air layer
directly above to the dew-point
temperature |
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