Download A mass of moist, stable air gliding up and over these mountains

A mass of moist, stable air gliding up and over these mountains
condenses into lenticular clouds.
Figure 7.1 When rock A is disturbed, it will returns to its original
position; rock B, however, will accelerate away from its original
position.
Figure 7.2 The dry adiabatic rate. As long as the air parcel
remains unsaturated, it expands and cools by 10ºC per 1000 m;
sinking parcelcompresses and warms by 10ºC per 1000 m.
Figure 7.3 An absolute stable atmosphere occurs when the
environmental lapse rate is less than the moist adiabatic rate.
Figure 7.4 Could surface air, on this morning, produces a stable
atmosphere that inhibits vertical air motions and allows the fog
and haze to linger close to the ground.
Figure 7.5 The layer x-y initially 1400 m thick. If the entire layer
slowly subsides, it shrinks, in the more-dense air near the surface.
As a result of the shrinking, the top of the layer warms more
than the bottom, and the entire layer (x´-y´) becomes more stable,
and in this example forms na inversion.
Figure 7.6 An absolute unstable atmosphere occurs when the
environmental lapse rate is greater than the dry adiabatic rate.
Figure 7.7 conditionally unstable air. The atmosphere is stable if the
rising air is unstable (a), but unstable if the rising air is saturated (b).
Figure 7.8 When the environmental lapse rate is greater than the dry adiabatic
rate, the atmosphere is absolutely unstable. When the environmental lapse
rate is less than the moist adiabatic rate, the atmosphere is absolutely stable.
And when the environmental lapse arte lies between the dry adiabatic rate and
the moist adiabatic rate (shaded green area), the atmosphere is conditionally
unstable.
Figure 7.9 Unstable air. The warmth from the forest fire heats the air, causing
instability near the surface. Warm, less-dense (and smoke) bubbles upward,
expanding and cooling as it rises. Eventually the rising air cools to its dew
point, condensation begins, and a cumulus cloud forms.
Figure 7.10 Mixing tends to steepen the lapse rate. Rising,
cooling air lowers the temperature toward the top of the layer,
while sinking, warming air increases the temperature near the
bottom.
Figure 7.11 The lifting of na entire layer of air (x-y_ tends to
increase the instability of the layer.
Figure 7.12 Convective instability. The layer a-b is initially
absolutely stable. The lower part of the layer is saturated, and the
upper parts is “dry”. After lifting, the entire layer (a´-b´) becomes
absolutely unstable.
Figure 7.13 The primary ways clouds form: (a) surface heating and
convection; (b) forced lifting along topographic barriers; © convergence of
surface air; (d) forced lifting along weather fronts.
Figure 7.14 Cumulus clouds form as hot, invisible air bubbles detach
themselves from the surface, then rise and cool to the condensation
level. Below and within the cumulus clouds, the air is rising. Around
the cloud, the air is sinking.
Figure 7.15 Cumulus clouds building on a warm summer
afternoon. Each cloud represents a region where thermals are
rising from the surface. The clear areas between the clouds are
regions where the air is sinking.
Figure 7.16 The development of a cumulus cloud.
Figure 7.17 The air’s stability greatly influences the growth
of cumulus clouds..
Figure 7.18 Cumulus clouds developing into thunderstorms in a
conditionally unstable atmosphere over the great Plains. Notice
that, in the distance, the cumulonimbus with the anvil top has
reached the stable part of the atmosphere.
Figure 7.19 During the summer, cumulus cloud bases typically increase in
elevation above the ground as one moves westward into the drier air of the
Central Plains.
Figure 7.20 Orographic uplift, cloud development, and the
formation of a rain shadow.
Figure 7.21 Lenticular clouds (mountain wave clouds) forming
over Mt. Shasta in Northern California.
Figure 7.22 Horizontal lines of pressure decreasing with altitude,
and vertical lines of temperature in ºC increasing toward the
right. The height values on the far right are approximate
elevations that have been computed assuming that the air
temperature decreases at a standard rate of 6.5ºC per kilometer.
Figure 7.23 In this figure, the slanted solid red lines are called
dry adiabatics. They show how the air temperature would
change inside a rising or descending unsaturated air parcel.
Figure 7.24 The sloping dashed blue lines in this figure are
called moist adiabats. They show how the air temperature
would change inside a rising or descending parcel of saturated
air.
Figure 7.25 The sloping gray lines in this figure are lines of
constant mixing ratio.
Figure 7.26 The adiabatic chart. The arrows in the chart
illustrate the example given in the text.
Figure 7.27 The formation of lenticular clouds.
Figure 7.28 Satellite view of cloud streets, rows of stratocumulus
clouds forming over the warm Georgia landscape.
Figure 7.29 Billow clouds forming in a region of rapidly
changing wind speed, called wind shear.
Figure 7.30 An example of altocumulus castellanos.
Figure 7.32 The mixing of a moist layer of air near the surface can produce a
deck of stratocumulus clouds.