UPP (develop)
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Subroutine that computes storm relative helicity. More...
Go to the source code of this file.
Functions/Subroutines | |
subroutine | calhel2 (llow, lupp, depth, ust, vst, heli, cangle) |
This routine computes estimated storm motion and storm-relative environmental helicity. | |
Subroutine that computes storm relative helicity.
Definition in file CALHEL2.f.
subroutine calhel2 | ( | integer, dimension(ista_2l:iend_2u,jsta_2l:jend_2u), intent(in) | llow, |
integer, dimension(ista_2l:iend_2u,jsta_2l:jend_2u), intent(in) | lupp, | ||
real, dimension(2), intent(in) | depth, | ||
real, dimension(ista_2l:iend_2u,jsta_2l:jend_2u), intent(out) | ust, | ||
real, dimension(ista_2l:iend_2u,jsta_2l:jend_2u), intent(out) | vst, | ||
real, dimension(ista_2l:iend_2u,jsta_2l:jend_2u,2), intent(out) | heli, | ||
real, dimension(ista_2l:iend_2u,jsta_2l:jend_2u), intent(out) | cangle | ||
) |
This routine computes estimated storm motion and storm-relative environmental helicity.
(Davies-Jones et al 1990) the algorithm processd as follows.
The storm motion computation no longer employs the Davies and Johns (1993) method which defined storm motion as 30 degress to the right of the 0-6 km mean wind at 75% of the speed for mean speeds less than 15 m/s and 20 degrees to the right for speeds greater than 15 m/s. Instead, we now use the dynamic method (Bunkers et al. 1988) which has been found to do better in cases with 'non-classic' hodographs (such as Northwest-flow events) and do as well or better than the old method in more classic situations.
[in] | LLOW | Lower bound CAPE>=100 and CINS>=-250. |
[in] | LUPP | Upper bound CAPE< 100 or CINS< -250; allows one to distinguish 0-3 km and 0-1 km values. |
[in] | DEPTH | Depth in meters over whcih helicity should be computed; allows one to distinguish 0-3 km and 0-1 km values. |
[out] | UST | Estimated U Component (m/s) Of Storm motion. |
[out] | VST | Estimated V Component (m/s) Of Storm motion. |
[out] | HELI | Storm-relative helicity (m**2/s**2). |
[out] | CANGLE | Critical angle. |
Date | Programmer | Comments |
---|---|---|
1994-08-22 | Michael Baldwin | Initial |
1997-03-27 | Michael Baldwin | Speed up code |
1998-06-15 | T Black | Conversion from 1-D to 2-D |
2000-01-04 | Jim Tuccillo | MPI Version |
2000-01-10 | G Manikin | Changed to Bunkers method |
2002-05-22 | G Manikin | Now allow choice of computing helicity over two different (0-1 and 0-3 km) depths |
2003-03-25 | G Manikin | Modified code to compute mean winds using arithmetic averages instead of mass weighting; differences are minor but want to be consistent with the Bunkers method |
2004-04-16 | M Pyle | Minimal modifications but put into NMM WRFPOST code |
2005-02-25 | H Chuang | Add computation for ARW A grid |
2005-07-07 | Binbin Zhou | Add RSM for A grid |
2019-09-03 | J Meng | Modified to compute effective helicity and critical angle |
2021-09-02 | Bo Cui | Decompose UPP in X direction |
Definition at line 48 of file CALHEL2.f.
References exch().
Referenced by miscln().