Hodographs. Assignment 9. Due March 30

Discussion: review information in the Djuric text on hodographs.

5 soundings are provided for 00UTC 1 March 2004: RAP, DNR, ILX, EYW, and SLC. Wind speeds are in m/s. Assume that the winds are approximately in thermal wind balance with the mean temperature field.

1. What are the official names of these locations and where are they?

2. For each hodograph and for each significant layer (not every bump and wiggle):

• a. Label the direction of warm/cold mean temperature as a function of height
• b. Indicate the type of advection (warm/cold/none) of the mean temperature by the mean wind through the layer.
• c. Indicate whether the structure in each significant layer is: barotropic; equivalent barotropic; or baroclinic
• d. Identify the 100 mb layer in which the advection of the mean temperature by the mean wind is the strongest.
• e. For the layer in part d, using the latitude of the station and the magnitude of the thermal wind, compute the magnitude of the horizontal gradient (degree C/degree lat) in mean temperature.

3. Identify the level in the upper troposphere where the wind speed is a maximum. What is the direction of the warmest and coldest air above and below this level?

4. Identify layers in which the winds are not likely to be in geostrophic wind balance. Why are they not likely in geostrophic wind balance?

5. Identify levels (if any) where the stability is destabilizing, i.e., cold advection above warm advection, or stabiliziing, i.e., warm advection above cold advection.