Question

Meteorology 10 Homework #5 Directions: Solve the problems below based on the material covered in lectures 14 and 15. You may work with others, but you must submit your own paper, in your own handwriting, and you must show your work! Any violation of that will earn you a zero! 1. (2pts) Categorize these atmospheric lapse rates into Stable Atmosphere, Conditionally Unstable, Absolutely Unstable Atmosphere. a. 11°C/1000m b. 2°C/1000m c. 7°C/1000m d. 5°C/1000m e. 15°C/1000m f. 8°C/1000m 2. (2pts) A completely moisture-less parcel of air with a surface temperature of 27°C is lifted off the ground. a. What is the parcel's Temperature at 2000m? 3000m? 4000m? b. Now suppose that the atmosphere's surface temperature is 19°C with a lapse rate of 8°C/1000m. How high could the parcel of air rise before it reaches equilibrium with the atmosphere's air temperature?

Answer 1

1. We will follow the following approach.

Since data is not given in question, approx values will be taken.

Dry Adiabatic Lapse Rate (DALR) = 10oC/1000m

Moist Adiabatic Lapse Rate (MALR) = 6oC/1000m

Atmospheric Lapse rate/Environment Lapse Rate(ELR) = given in questiion

The conditions for stability/instability are :

if ELR<WALR<DALR then Absolute Stability

because here the rising air mass cools faster than the surrounding air, hence will sink.

if WALR<DALR<ELR then Absolute Instability

bcause here the rising air mass will cool slower as compared to surrounding air, hence always remain buoyant and rise

if WALR<ELR<DALR then conditional Instability

using above knowledge,

a. Absolute unstability

b. Absolute stability

c. Conditional instability

d. Absolute stability

e. Absolute instability

f. Conditional Instability

2.

a. Completely moisture less air, thus the air parcel will cool with Dry Adiabatic Lapse Rate (DALR) of 10oC/1000m

Hence, temperature at 2000m = 27- 20

= 7o C

temperature at 3000m = 27- 30

= -3o C

temperature at 4000m = 27- 40

= -13o C

b. Given,

Surface temperature of air parcel = 27 oC

it cools with DALR of 10oC/1000m

Surface temperature of armosphere = 19 oC

Atmospheric Lapse Rate = 8oC/1000

To find our height for equilibrium -

ELEVATION	TEMP OF PARCEL(DALR)	TEMP. OF SURROUNDING AIR	STABILITY
1000m	17oC	11oC	unstable
2000m	7oC	3oC	unstable
3000m	-3oC	-5oC	unstable
4000m	-13oC	-13oC	equilibrium

Thus, the air parcel would rise 4000 m before it reaches equilibrium condition with surrounding air.