WMOD00513

• Title: Predictor Variables of the Maximum Radar Echo Activity on Convective Days
• Date: 3/1/1979
• Weather Modification - Doc Type: Report

MARCH 1980

NOTES

336

TABLE 2. Cross correlation table of predictor variables. Circled values are correlations greater than 0.49
between variables which were not grouped in the same category.

<

/"~~I

~
,,'" ,(.,
~ ,,<:,'"

~
~' ~o
'v 'v
" "

~
~'"
<t

~
~.,
<t

...
..."
<t~ ~<>c

~
~..
<t

T SFC 11.00, .59 .57

EV'20 1.00

.29 -.02 .21

.15

.15

.1 ~

.18 -.21

.85 G .2~ .25 .~7 .45 .4~ .41

G .27 .~4 .~7 .47

-.09 '.05 .08

LEVo 1.00

.47

.46 -.21 -.1 5 .2~

/

~ ~ ~ ~
~1Ioj Q:-ft) Q:-'" Q:-ltl
j' i' j' j'

~ ~ ~
~"" c::J" c::J't)
~ ~ ~
~ ~ ~
:":\
.12 .05 -.~~ -.6j

.05 .00 -.~9 8

<>c ~
.i <t<:''''
~'" ~'"

~
....'
"

~ A..,.....
:: A... ~
-.29 8 .2~ .57

e .49
.12 .65 G .29

-.42 .57

-.4~ .60
.../

.10 .71

.42 .26 -.40 .60 .12

.20 -.11 -.40

EPT,OO 1.00 .33 .~2 .48 .70 .74 .52 -.14 -.06 ,02 .30 .~7 .14 .10 -.44 G .06 .02 -.~2 -.~I

TOSFC 1.00 .64 .74 .70 .68 .8~ -.73 -.71 .46 .53 -.15 -.09 -.0788 -.20 .10 -.06 -.19

PW.,o 1.00 .61 .62 .62 .72 -.73 -.68 .63 .47 -.06 .09 .0 I G G .08 .14 .05 -.12

PW700 1.00 ,91 .89 .92 -.75 -.70 .50 .71 -.12 .02 .04 86 -.08 .O~ -.20 -.17

PW,oo 1.00 .99 .87 -.62 -.55 .39 .75 -.04 .02 -.10 88 -.10 -.06 -.21 -.14

PWTOT 1.00 .85 -.60 -.52 .36 .73 -.04 -.06 -.11 GG -.08 -.05 -.19 -.12

MR 1.00 -.85 -,80 .61 .65 -.09 .01 .02 88 -.07 .17 -.23 -.22
:'\
LIIOO 1.00 .97 -.90 -.12 .24 .09 .05 .5':; -.40 -.02 -.28 .O~ .04

LI,o 1.00 -.91 -.71 .24 -.01 -.09 G -.42 -.01 -.25 .07 .18

TT! 1.00 .65 -.08 .07 .10 -.44 .39 .17 .33 -.01 -.12

K I 1.00 -.28 -.24 -.22 G .41 .11 -.14 -.11 .02

WOIR300 1.00 .59 .37 -.05 .36 .06 .19 -.17 -.46

ficient was 0.73 and occurred between maximum
5 min rain volume and 70 kPa wind speed. In nine of
the dependent variable classes, the wind speed term
had the highest individual correlation coefficient
seven times and was second highest in the other
two. However, it was so insignificant in the maxi-
mum echo height Class that it was not entered into
the regression equation.
The water vapor-stability category also correlated
fairly well. It had the highest individual correlation
coefficient in three of the classes and the second
highest in four others. The stability index variable
emerged as the most highly correlated in this cate-
gory for six of these seven occurrences.

WOIR,OO 1.00 .69 -.08 .26 .32 .21 -.29 -.75

WOIR700 1.00 -.07 .19 .23 .21 -.28 -.85

WOIR.,O 1.00 -.95 .22 .20 .30 .38

WSHEAR

Ir~
1.00 -.18 -.13 -.33 1'\.:5~

WSP0300 1.00 .73 .30 .00

WSPD,OO 1.00 .21 -.07

WSP0700 1.00 .49

WSP0150 1.00
'----

The multiple correlation coefficients (Mult R)
ranged from 0.76 to 0.83 for all cases except the
maximum reflectivity class which had a value of
0.62. Mult R2 is the variance explained by the model
being tested and ranges from 58 to 69% except for
maximum reflectivity in which the explained vari-
ance was 38%. The dominance of the wind speed
and water vapor-stability terms shows up in the mul-
tiple regression analyses also. The wind speed and
water vapor-stability terms were the first two to be
entered into the equation during the stepwise pro-
cedure for eight cases (exceptions: maximum echo
height and maximum total area exceeding 10 dBz).
The average improvement to Mult R for these eight