Thermal Wind and Mean Temperature Advection. Assignment 8. Due March 23

Review the information on thermal wind in the Djuric text.

Model forecast guidance from the Eta model initialized at whatever time you choose will be used. In other words, use only 1 analysis time.

Use Garp to access the model forecast sequence.

You must turn in maps for each part (otherwise I won't be able to see what you are discussing.)

1. Plot 300 mb height and geostrophic wind. Identify upper tropospheric troughs and ridges and where the strong winds aloft are found.

2. Plot 700 mb height and geostrophic wind. Identify lower tropospheric troughs and ridges and where the strongest winds are at 700 mb.

3. Plot 500 mb temperature. Overlay the thickness of the 300-700 mb layer. How do the two fields compare? Where is the warmest/coldest temperature at 500 mb? Highest/lowest 300-700 mb thickness? Where is the warmest/coldest 500 mb temperature and highest/lowest 300-700 mb thickness relative to the 300 mb and 700 mb troughs and ridges? For the second part, be sure that you specify Layer 1 to be 300 and Layer 2 to be 700.

4. Clear the screen, plot 300 mb height, 700 mb height, and the thickness of the 300-700 mb layer all at 60 m contour interval. Where do the thickness contours intersect the 300 and 700 mb contours?

5. Clear the screen. Overlay the thickness of the 300-700 mb layer and the thermal wind of the 300-700 mb layer. What is the relationship of the thickness to the thermal wind? Relative to the direction from which the thermal wind is "blowing" what direction is the cold and warm air? Where is the 300-700 mb thickness gradient the largest? Where is the 300-700 mb thermal wind the strongest in magnitude?

6. Clear the screen. Overlay the thickness of the 300-700 mb layer and the mean wind of the 300-700 mb layer. Overlay also the advection of the mean temperature/thickness of the 300-700 mb layer by the mean wind of the 300-700 mb layer. Where is the largest warm air advection in the layer? Largest cold air advection? How does the temperature advection relate to the position of the 300 mb and 700 mb troughs and ridges?

7. Plot on a polar diagram for at least 3 different types of weather situations found on your analysis, the relative magnitude and direction of the 700 mb and 300 mb geostrophic wind and thermal and mean wind of the 300-700 layer. Indicate on the diagram the location of cold and warm air and indicate if there is warm, none, or cold air advection of the mean temperature of the 300-700 mb layer by the layer averaged wind.