LAB 6 Due Friday Oct 17 th Chapter 8 Question 1 abc Radiosonde instrument carried by a weather balloon to measure atmospheric variables such as temperature pressure relative humidity ID: 557570
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Slide1
METEO 003
LAB 6 Due Friday Oct. 17
thSlide2
Chapter 8 Question 1 a,b,c
Radiosonde: instrument carried by a weather
balloon
to measure atmospheric variables (such as temperature, pressure, relative humidity,
etc
) in the vertical direction
Lapse rate is the rate of decrease of temperature with altitude
Dry Adiabatic Lapse Rate: 10°C/km
Moist Adiabatic Lapse Rate: 6°C/km
Layer lapse rate =
temperature (bottom of layer) – temperature (top of layer)
thickness of layer (distance from top to bottom)Slide3
Stability Review
Stable Equilibrium (“Stable” atmosphere)When a parcel is moved upward or downward, forces act to return it to it’s original altitude (bowl with ball in it)
Unstable Equilibrium (“Unstable” atmosphere)
When a parcel is moved upward or downward, forces act to accelerate it away from it’s original altitude (upside-down bowl with ball on top)Slide4
Chapter 8 Question 1 a,b,c
Ways to test stability:
Compare lapse rate of layer to dry and moist adiabatic lapse rates
Stable: Layer lapse rate
<
6°C/km (
Γm
)
Unstable: Layer lapse rate
>
10°C/km (
Γ
d
)
Conditionally unstable: Layer lapse rate is between 6°C/km and 10°C/km
Lift parcel of air from bottom of layer to top of layer (cool air parcel by dry or moist lapse rate)
Stable: temperature of air parcel is colder than
environment after lifting the parcel
Unstable: temperature of air parcel is warmer than
environment after lifting itSlide5
Chapter 8 Question 2 a,b,c,d
Windward Side of Mountains: rising motion and clouds
Leeward side of Mountains: sinking motion and rain shadow
Use information on the last three slides to do this problem
Example:
Wind is forcing air originating at sea level (0m) to rise over a mountain with a peak of 3000m. Temperature and dew point of air at sea level is originally 20°C and 5°C respectively. Environmental temperature at peak of mountain is 0°C.
Questions:
a. What elevation will a cloud form?
b. What will the temperature of the
rising air
be once it reaches the peak of the mountain?
c. Is the
atmosphere
at the peak unstable
or stable?
d. What will the temperature of the air be once it sinks down the other side of the mountain? Slide6
Example
Wind is forcing air originating at sea level (0m) to rise over a mountain with a peak of 3000m. Temperature and dew point of air at sea level is originally 20°C and 5°C respectively. Environmental temperature at peak of mountain is 0°C.
Questions:
a. What elevation will a cloud form? (assume constant dew point)
20°C - 5°C = 15°C
difference between temperature and dew point
Air Parcel needs to cool 15°C so:
10°C
=
15°C
10x°C = 15°C*km
1 km x x = 1.5km = 1500m
1500m – 0m (sea level) =
1500m
is the elevation the parcel must rise for a cloud to formSlide7
Example
Wind is forcing air originating at sea level (0m) to rise over a mountain with a peak of 3000m. Temperature and dew point of air at sea level is originally 20°C and 5°C respectively. Environmental temperature at peak of mountain is 0°C.
Questions:
b. What will the temperature of the air be once it reaches the peak of the mountain?
3000m – 1500m = 1500m still to rise from cloud formation to peak of mountain
So:
6 °C
=
_ x
_
1x km = 9°C*km
1 km 1.5 km x = 9
°C
5
°C – 9 °C =
-4 °C
is the temperature of the air parcel once it reaches the peakSlide8
Example
Wind is forcing air originating at sea level (0m) to rise over a mountain with a peak of 3000m. Temperature and dew point of air at sea level is originally 20°C and 5°C respectively. Environmental temperature at peak of mountain is 0°C.
Questions:
c. Is the
atmosphere at the peak
unstable or stable?
Temperature of air parcel at the peak of the mountain is -4 °C vs an environmental
temperature at the peak of the mountain of 0
°C so the air parcel is negatively buoyant and
stable
Slide9
Example
Wind is forcing air originating at sea level (0m) to rise over a mountain with a peak of 3000m. Temperature and dew point of air at sea level is originally 20°C and 5°C respectively. Environmental temperature at peak of mountain is 0°C.
Questions:
d. What will the temperature of the air be once it sinks down the other side of the mountain? (assume unsaturated now)
Air Parcel needs to
sink 3000m so
:
10°C
=
x
1x km
=
30°C*km
1
km
3 km x = 30
°C
30
°
C
+ -4
°C
=
26
°C
is the temperature of the air parcel when it
descends
back to sea level
* this is warmer than it originally was at sea level before
traveling
over
the mountainSlide10
Chapter 8 Question 7 a,b
Assuming air is
unsaturated…use dry adiabatic lapse
rate
Standard room temperature is
~70-77
⁰F
so for Part
B
think about if that air temperature is comfortable immediately after it was pressurizedSlide11
Chapter 8 Question 9
a Unstable: Bubbly appearance
Stable: flat appearanceSlide12
Chapter 8 Question 11 a,b
For Part
A
: also state what the wind direction is
Look at cloud type/texture of clouds on visible image and relate that to stability
What can be said about the temperature near the ground/water assuming the air up above is the same temperature over the entire image area?Slide13
Chapter 9 Question 2
Speed of sound [m/s] = 20*sqrt
(T [K])
*note temperature is in Kelvins
Converting Fahrenheit to Celsius: ⁰C = 5/9(⁰F - 32)
Converting Celsius to Kelvin: K = ⁰C + 273.15
Speed [m/s] = distance [m] / time [s]
Rearrange equation to get: Time [s] = distance [m] / speed [m/s]Slide14
Chapter 9 Question 6 a,b
Height of cloud base for a thunderstorm would be where the temperature and dew point are equal (air becomes saturated)
Use dry adiabatic lapse rate here to determine height of cloud base
*
HINT for Part B
:
High-based t-storms lead to evaporation of the rain before it reaches the ground, which leads to fires
Figure 9.26Slide15
LAB 6 Due Friday Oct. 17th
8.1a(5),b(5),c(3)
Dry Adiabatic Lapse Rate:
10°C/km,
Moist Adiabatic Lapse Rate:
6°C/km
8.2a(2),b(2),c(2),d(2)
reference the example
8.7a(3),b(2)
Sinking air warms
8.9a(2)
flat or bubbly appearance?
8.11a(2),b(4)
To part a add "what is the wind direction?" Look at cloud type and relate to stability. What does that say about the temperature near the ground/water assuming the air above is the same temperature over the land and water?
9.2 (3)
Convert temperature from Fahrenheit to Kelvin conversion
[
⁰
C = 5/9(⁰F - 32
), K
= ⁰C
+
273.15]
9.6a(2),b(1)
High-based t-storms lead to evaporation of the rain before it reaches the ground, which leads to fires