Reference no: EM132591768

GEO-112 Stability and Adiabatic Processes Lab Assignment -

Humidity and temperature characteristics of an air mass are key parameters in determining the stability of the air. Conditions in the environment determine whether a mass of air will lift, cool by expansion, and become saturated - unstable conditions - or whether it will resist displacement (uplift) - stable conditions. This exercise examines stability aspects of air masses and adiabatic processes.

Part 1 - Atmospheric Stability

1. Determining the degree of stability or instability involves measuring and comparing simple temperature relationships between conditions inside an air parcel and the surrounding air. This difference between an air parcel and the surrounding environment produces a buoyancy that contributes to further lifting. The three possible conditions are:

Stable - if the rising air is cooler than the surrounding air

Unstable - if the rising air is warmer than the surrounding air

Conditionally unstable - if the rising air is cooler than the surrounding air while unsaturated but becomes warmer than the surrounding air once it is saturated.

2. Using the figure on page 2, determine which stability condition describes each of the three graphs in question 1 based on the relationship between the adiabatic rates and the ELRs.

Part 2 - Unstable and Conditionally Unstable Conditions

3. On the graph on the next page, set up a graph similar to those used in question 1. Label the X-axis as "Temperature ^oC" and add values for it from -20^o to 35^o. Label the Y-axis as "Altitude (meters)" and add values for it from 0 to 6000.

4. Imagine that an air parcel with a specific humidity of 5.4 g/kg and an internal temperature of 25^oC begins to lift. Assume an ELR of 12 C^o/1000 m in the surrounding environment. Use the standard DAR and MAR.

5. What is the dew-point temperature at which a rising parcel with the conditions described will become saturated?

6. How much cooler will the parcel be when it reaches that dew-point temperature?

7. Given that the parcel will cool at the DAR until it reaches its dew-point temperature, how many meters will the parcel rise before it cools to its dew-point?

8. Start a new line on the graph to represent the temperature profile of the rising air mass using the DAR from the surface, starting at 25^oC, to the altitude at which the parcel reaches its dew-point temperature.

9. Is the parcel of air stable or unstable at 1000 m altitude? Explain.

10. Continue the line you started in question 8, using the MAR, from the lifting condensation level up to the top of the graph.

11. What is the temperature of the parcel at 3500 m? What is the maximum specific humidity at that temperature? What is the difference in specific humidity (g/kg) between the parcel when it was on the surface and at 3500 m? Where did that moisture go?

Part 3 - Orographic Lifting and Rain Shadows

12. The air mass begins in Fresno with a temperature of 10^oC and a relative humidity of 50%. What is the specific humidity of the air mass? What is the lifting condensation level for this air mass?

13. Mark the lifting condensation level on the diagram on the next page.

14. Fill in the temperature, specific humidity, relative humidity, and grams of water lost for the journey of this air mass from Fresno to Death Valley.

15. Do you live on the windward or leeward (rain shadow) side of the nearest major terrain feature? What is the terrain feature that controls your precipitation?

Attachment:- Lab Assignment File.rar