ASP lab response case: 23 June 2008
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Introduction
Several data fields from a CSU-CHILL RHI scan through a thunderstorm are shown below. A few questions are listed below the polarimetric data field plots. Please submit your answers as an e-mail with a subject of "23 June 2008" sent to:
asp@chill.colostate.edu
NOTE: You may complete your responses and send the e-mail outside of the basic polarization lab period.
For general reference, here is the basic reflectivity (Zh) data from the storm:
Differential Reflectivity (Zdr)
1.) Based on the reflectivity and differential reflectivity data, what is the dominant form of precipitation at the points marked in the Zdr plot?
1a:
1b:
1c:
2.) Consider the vertical profile of Zdr along the vertical line marked as point 2 in the Zdr image. What is the probable cause of the locally positive Zdr layer located near the 2 km AGL height line?
2:
Differential Propagation Phase (Phidp)
3a.) Over what range interval does the greatest phidp change take place?
3a:
3b.) The presence of what hydrometeor type is causing this increasing lag between the H and V return signals?
3b:
Co-polar Correlation between the H and V Returned Signals (RhoHV)
The correlation field has a local relative minimum of ~0.95 at the point marked.
4. What precpitation composition is probably responsible for this?
4:
Linear Depolarization Ratio (LDR)
5a: A local maximum (~-23 dB) in linear depolarization is seen at point 5a. What hydrometeor type is responsible for this?
5a:
5b: There is also a general tendency for the LDR values to become large in the more didtant and/or weaker reflectivity portions of the echo. (Point 5b for example). Why should the LDR values tend to increase in these areas?
5b:
Remember: Submit your responses to questions 1 - 5b to asp@chill.colostate.edu with the subject line "23 June 2008".