Boundary Layer Convergence Zones, Boundary Layer Convection, and CI

Lab Overview:

The purpose of this lab is to gain experience looking at and analyzing clear-air radar data that resolves a variety of boundary layer convergence zones and the convection they initiate.  You will examine how these boundaries interact with each other to initiate convection and the characteristics of the boundaries.  The data sets were collected during the Convection and Precipitation/Electrification Experiment (CaPE). This experiment occurred during the summer of 1991 over east-central Florida. 

1.  You can analyze one of the following two data sets:

• Set your DORADE_DIR environmental variable to /mnt/arch/cases/12aug91.
• Set your DORADE_DIR environmental variable to /mnt/arch/cases/02aug91.

All text and imagery should be placed in a ppt file.  You will turn in a ppt file for this lab.

2.  The primary phenomena and processes that you will focus on in this lab are:

• the movement and evolution of all boundary layer convergence zones (thin lines)
• how the boundary layer convergence zones initiate convection
• the evolution of boundary layer convection
• severe surface winds produced by the convection (microbursts)

3.  Become familiar with the data set by examining the SUR scans at 0.3 degrees elevation throughout the entire day.  After doing so, answer the following questions.  Please included annotated graphics to support your answers.

1. When do you first see the sea-breeze thin line along the coast?
2. Does the coastal orientation affect the sea-breeze thin line structure?  Explain.
3. Does the sea breeze inland penetration speed vary throughout the day?  Explain.
4. Describe the evolution of the sea breeze frontal strength based on observations of the sea breeze thin line.  Explain this evolution based on the concepts discussed in class.
5. Describe the evolution of boundary layer convection observed in your data set.  What types of boundary layer convection do you observe?  When are they observed?
6. Based on the movement of the boundary layer convection, what is the ambient wind direction?
7. For all convection within 80 km of the radar, provide a physical explanation for how it was initiated.
8. Throughout the day, document and physically describe all boundary interactions.
9. Do gust fronts tend to move faster or slower than the sea breeze?  Explain.
10. Document any microburst-producing storms.  Make sure to show the Doppler velocities when documenting their existence.