Updraft helicity and SRH in the Southern Hemisphere

[Gabriel Cassol]

Hello everybody,

Is it possible to update the post-processing codes used to calculate the storm relative helicity (SRH) and updraft helicity (UH) for the Southern Hemisphere?

/sorc/ncep_post.fd/CALHEL.f
/sorc/ncep_post.fd/CALUPDHEL.f

From what I saw in the SRH code, the left movement of the average wind is not taken into account, and in the code to calculate the UH I did not find adaptations to find the negative ascending helicity, so I should look for the minimum values of UH, in Southern Hemisphere cases.

 

[Ming Chen]

UPP is maintained by the DTC lab at NCAR. We use it as is. Please take a look at this website to find support information:

Community Code | Legacy Tools | dtcenter.org

dtcenter.org

 

[kwerner]

UPP staff check this forum from time-to-time and will hopefully be able to assist with your question.

 

[hertneky]

This issue is being addressed in the UPP Github issue #532. Please check there for updates.

 

[hertneky]

An enhancement was made to the UPP source code to account for the left-mover in the southern hemisphere for SRH and was merged into the develop branch on Oct 10th 2022.

For updraft helicity, the algorithm does not change for the southern hemisphere. For the SH, rising cyclonic (anti-cyclonic) rotation will have negative (positive) values.