Stability and Stuves

In this lab we will be exploring stuve diagrams, and how we can use them to determine the stability of the atmosphere.

Part I Learning about the Stuve

A stuve diagram is a way that meteorologists plot upper air data, that makes it easier to analyze and use for weather forecasting. Upper air data are meteorological measurements collected from radiosondes or rawinsondes, also known as weather balloons. These instruments collect data on temperature, humidity (dewpoint temperature), wind speed and direction, and pressure. Here is a short video on the weather balloon launch process in Greenland:

AGU 2014 Student Videos – Kathleen Willmot (Links to an external site.)

To learn more about stuve diagrams, what they are, and how they are used, please read through this tutorial:

http://www.csun.edu/~hmc60533/CSUN_103/weather_exercises/soundings/smog_and_inversions/Understanding%20Stuve_v3.htm (Links to an external site.)

Part II Downloading Stuve Diagrams

In this section we will go through a short tutorial on how to find stuve diagrams.

One of the best sources for these diagrams is the Plymouth State Weather Center. Navigate to the website below, and follow the instructions:

http://vortex.plymouth.edu/ (Links to an external site.)

1. From the main page look for the menu on the top that says “Upper Air” and select “Make Your Own”

2. Under “Diagrams/Data” click on “Archived (WXP)”

3. Select the following values

Type Output: Stuve Diagram

Date: 1999, August, 11

Time: 12Z

Parcel Path: No Plot

Chart Size: 640×480

Web/Print: Print Only

4. Once you have the above selected, click on the “KSLC” station on the map of the United States.

5. You should now see a stuve diagram for Salt Lake City on the date above. Right click (or ctrl click) and select “Save image as…” Save the image and when you are submitting your assignment UPLOAD it so I know you completed this part.

*The stuve plot you have downloaded is for the day of the Salt Lake City tornado. See here for more information:

http://en.wikipedia.org/wiki/1999_Salt_Lake_City_tornado (Links to an external site.)

6. Now, download one more stuve diagram for a date and location of your choosing. Save this image as well, and when you are submitting your assignment UPLOAD it so I know you completed this part.

Part III Plotting and Calculating

In this last section you will now plot your own stuve diagram, and then calculate lapse rates for each of the atmospheric layers.

You will need the data sheet:

StuveLab x

Actions

And a blank stuve diagram:

bstuve1.gif

While you can likely complete the data sheet on your computer, you might need to print out the stuve diagram to complete the plotting part. Print the blank stuve diagram. Plot the temperature and dewpoint data on the chart. Scan or photograph and upload with your submission. Be sure you also upload the completed data sheet.

Follow all instructions and answer all the questions on the data sheet.

Hint: When plotting the stuve diagram it will be easier to plot using the pressure values, rather than the height values for your y axis.

Hint2: For the final questions, it may be helpful to use your book for reference on the differences between stable, unstable, and neutral, as well as the WALR and DALR.

Upper Air Diagrams, Lapse Rates, & Stability NAME ___________________________

Meteorologists use upper air diagrams to diagnose moisture in the atmosphere and stability to help predict the weather. Today you will be creating an upper air diagram and determining what it says about the stability of the atmosphere.

1. Using the data below, plot the Temperature and Dewpoint on the attached blank upper air diagram. Make sure it is clear which line is T and which is Td.

2. Using the Height and Temperature data in the chart below determine the change (∆) of Temperature and Height in each layer. Use these numbers to calculate the lapse rate:

Lapse Rate = ∆ T/∆ H

72233 LIX Slidell Muni Observations at 12Z 30 Jan 2014

—————————————————————————–

PRES HGHT TEMP DWPT RELH MIXR DRCT SKNT ∆ T ∆ H ∆ H Lapse Rate

mb m C C % g/kg deg knot C m km C/km

—————————————————————————–

1000.0 209 -3.5 -19.5 28 0.82 90 18

950.6 610 -0.7 -32.8 7 0.26 135 10 ____ ____ ____ ____

897.0 1077 4.0 -45.0 1 0.08 47 4 ____ ____ ____ ____

850.0 1514 3.4 -23.6 12 0.67 310 8 ____ ____ ____ ____

787.1 2134 1.5 -24.1 13 0.70 295 16 ____ ____ ____ ____

757.9 2438 0.3 -23.4 15 0.77 290 22 ____ ____ ____ ____

700.0 3072 -1.7 -28.7 11 0.51 250 27 ____ ____ ____ ____

649.9 3658 -3.2 -37.2 5 0.24 265 27 ____ ____ ____ ____

600.0 4288 -6.3 -40.3 5 0.19 260 26 ____ ____ ____ ____

555.4 4877 -11.0 -42.5 6 0.16 260 27 ____ ____ ____ ____

500.0 5680 -17.5 -45.5 7 0.13 255 34 ____ ____ ____ ____

400.0 7310 -29.7 -49.7 13 0.10 245 52 ____ ____ ____ ____

351.0 8230 -37.4 -45.8 41 0.18 235 66 ____ ____ ____ ____

300.0 9310 -42.3 -62.3 9 0.03 235 88 ____ ____ ____ ____

250.0 10520 -48.3 -70.3 6 0.01 235 100 ____ ____ ____ ____

200.0 11980 -50.7 -79.7 2 0.00 240 91 ____ ____ ____ ____

150.0 13830 -57.9 -84.9 2 0.00 240 84 ____ ____ ____ ____

100.0 16310 -67.7 -87.7 4 0.00 260 58 ____ ____ ____ ____

3. The dry adiabatic lapse rate (DALR) is about -10 C/km and the wet or saturated adiabatic (WALR) is about -6 C/km. How do your lapse rates compare to these numbers? Are they less, greater, or in between?

4. What does this tell you about the stability of the atmosphere?