DELTT.dia
Time or distance has placed the particle in a lower pressure zone than the
original sounding 300.txt with a west wind. The transition layer is L=levl=53
or called the interface overlap between the 2 soundings.
==>
h[ ] m 300.txt
HL L 13518 ________________ ___
^ | #
| | 301.txt m #
| fps! o |______________ _ *13512 ctth L #
| | ^ %
2 | | | % 434 m
dz1= 8 |tt1 levl=53 | levl=53 | * %
7 | | | 4 %
m | | tt2 | 2 = dz2 new tt for dh
| | | 8 %
L1 13231 |_______________| | m %
h[ ] : | :
dt : | :
: | :
:_______________| 13084 ctth L1 _:_
We now want to continue down from the initial level (levl=53) with the new sounding
301.txt. For 300.txt @ levl=53, we have a thickness of h[L]-h[L1] here with L1=L-1,
13518-13231= 287m with an associated travel time tt1. However, for 301.txt on the right,
this levl=53 has a different height & thickness as h[L]-h[L1] = L1=L-1, 13512-13084= 428m.
Since the time increment between soundings is small (1 hr min) and the distance is just
> 25 km, then the predicted height changes should be similar - and there must be an
overlap or we will have to deal with a gap. In the case listed above, the height L1 @
300.txt on the left with it's associated travel time tt1. Both these new heights and
thicknesses need to be accounted for to calculate a new travel time tt that is considered
as one new combined layer 53 extended down to h[L1] of 301.txt on the right. Then we can
continue down from there downward in the rest of the 301.txt sounding.
Since we are really interested in only adjusting the travel time tt for the vector
translation of the layer, we will have to adjust (increase) tt by dt indicated by the
travel time distances of :'s and #'s. Now tt's is all we can calculate from pttct.150,
where 3 in the 300.txt is the m=3 or the 150 mb level. The first to know is the fvel
for standard particle size sp[m]. While reading 300.txt to convert to the usable
format \PHL\datetime.STA file, we have the dz=(h[n]-h[n1])*fpm in ttvect() then
tt1=dz/fps sec and tth=tt1/sph hrs. The sph = 3600'/sec and fpm=3.2808'/m. The fall
velocity fps on left ~= fps on right = dz2/tt2 where dz=428. Since the bulk of the
new layer will usually be represented on the left, we will use the left fps with the
tt1. Again, for this 1st initial layer (levl=53) for 301.txt, we find the bottom of this
same layer (levl=53) from 301.txt. So this initial layer is extended so we really only
need the combined new layer thickness. Notice, the * values means that we don't need
these values.
The new combined layer thickness dh = L@left -> l1@right = 13518-13084=434m. So before
we leave 300.txt, we save the height @ L as HL. Then we have a dh=HL-L1@301.txt. So now
the new travel time tt for the new dh layer is dh/fps sec or tth=tt/sph hrs. Thus, ctth
L1 @ 301.txt = ctth L @ 301.txt + tth = ctth @ L1 (13084m) for cortt() to begin to
rewrite 301.txt, which is really the copied 300.txt up to this point. Then we make use
of tth for the layer's de=del[n]*tth & dn=dnl[n]*tth, then the landing vector components
sums of de,dn or cde=cde+de & cdn=cdn+dn back in ttvect() before the rewrites in cortt().
-------------------------------------------------------------------------------------------
Time or distance has placed the particle in a higher pressure zone than the
original sounding 300.txt with an east wind.
<==
m 301.txt
*13518 ________________
ctth ^ | h[ ]
| | 300.txt m L
| |________________ 13512 ctth L ___ HL
* | | ^ %
2 | | fps! o | %
dz2= 8 |tt2 levl=53 | levl=53 | % 281 m
7 | | | 4 new tt for dh
m | | tt1 | 2 = dz1 %
| | | 8 %
L1 13231 |_______________| | m __%__
h[ ] ctth : |
dt : |
: |
:_______________| 13084 ctth L1
h[ ]
Now we simply change the wind direction with 300.txt blowing to the region 301.txt rather
than shifting layer positions with a new drawing. Now we want to contract the height
L1 @ 300.txt to L1 @ 301.txt. However, this new tt has to be shortened indicated by the
dt :'s again. The dh adjustment is taken care of if we just keep it as hl1 @ 300.txt-h[L1]
@ 301.txt. We sub hl1 for h[L1] @ 300.txt so the new dh=13512-13231=281m. Then tt for the
new dh layer is dh/fps sec or tth=tt/sph hrs as before.