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Task 2: Vertical structure and forecast evolution to day 10
This task focuses on the fate of Nadine and examines vertical PV cross-sections of Nadine and the cutoff at different forecast times to characterize the diabatic warm core PV tower of Nadine compared to the upper level PV cold core of the cutoff.
Right-click on the icon 'hres_xs.mv' icon, select 'Edit' and push the play 
button.
The plot shows the cross-section for the 22nd Sept., (day 2 of the forecast). The plot shows potential vorticity (PV), wind vectors projected onto the plane of the cross-section and potential temperature drawn approximately through the centre of the Hurricane and the cut-off low. The red line on the map of MSLP shows the location of the cross-section.
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Cross-section data is only available every 24hrs until the 30th Sept 00Z (step 240).
This means the 'steps' value in the macros is only valid for the times: [2012-09-20 00:00], [2012-09-21 00:00], to [2012-09-22 30 00:00], [2012-09-23 00:00], [2012-09-24 00:00], etc..
Change the forecast time to day+6 (26th Sept). Nadine has now intensified as it approaches the coast.To change the date/time of the plot, edit the macro and change the line:
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steps=[2012-09-2226 00:00] |
Changing cross-section location
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The cross-section location (red line) can be changed in this macro by defining editing the end points of the line as shown above.
If the forecast time is changed, the storm centres will move and the cross-section line will need to be repositioned to follow specific features. This is not computed automatically, but must be changed by altering the coordinates above.
Change the forecast time again to day+8 (28th Sept), relocate and plot the cross-section of Nadine and the low pressure system. Use the hres_1x1.mv icon from task 1 if you need to follow location of Nadine.
If time, try some of the other vertical cross-sections below.
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Q. What changes are there to the vertical structure of Nadine during the forecast? |
Cyclone phase space (CPS) diagrams
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| borderColor | red |
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| borderStyle | solid |
TODO:
Frederic : should we put your CPS diagrams in the metview folder?
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An objectively defined cyclone phase space (CPS) is described using the storm-motion-relative thickness asymmetry (symmetric/non-frontal versus asymmetric/frontal) and vertical derivative of horizontal height gradient (cold- versus warm-core structure via the thermal wind relationship). A cyclone's life cycle can then be analyzed within this phase space, providing insight into the cyclone structural evolution.
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