WMOD00299 ‎(2)‎

• Title: Scientific Weather Modification Experimentation in the United States
• Date: 8/25/1984
• Weather Modification - Doc Type: Report

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Table 1. Cloud ~lect1on Criteria for HIPLEX-1

Class A-I Cloud Criteria

1. Average cloud liquid .ater concentration greater than 0.5 g/m3 over
appro~1.ately a 1-km-long cloud region detena1ned by 10 s of flight
at approximately 100 _Is

2. Average 1ce-c~stal concentrations less than 1.0 per liter in the
1-tIl-long (10 s of flight) cloud region of .ad..m average liquid .ater
concentrlt ion

3. Maxi.u. ice-crystal concentration less than 5.0 per liter for Iny
1-tIl-long (10 s of flight) cloud region (defined by FSSP liquid .ater
concentration greater than 0.01 g/m3) during the test pass

4. Vertical air velocity greater than -1.0 fills in the region defined by
item I, but if the vertical velocity is greater than 10.0 m/s Ind the
buoyancy is greater than 1 .C. reject the candidate

5. Length of the test penetration aore than 2 k~ Ind less than 8 km as
defined by an FSSP liquid water concentration greater than 0.01 g/m3

6. No radar echo detectable on the aircraft weather radar

7. Cloud-top temperature lower than -6 .C but higher than -12 .e

8. eloud-base temperature higher than 0 .C

9. "ini~ separation between the current test cloud and previous test
clouds greater than 15 km to insure the meteorological independence of the
clouds

Class A-2 Cloud Criteria

1. Items A.l to A.9 above

2. An average wind direction betweer. the surface and 800 kPa from 2500 to
040. true

3. A 3D-kPa-thick stable layer present with its base between 0 to -10 .C
and its top temperature at least 1.5 .C higher than the temperature
extrapolated from the base of the layer to the top using pseudoadiaba-
tic ascent

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4. A 10 .C dewpoint depressing present somehwere within the 30-kPa layer
of B.3 above

Class B Cloud Criteria

1. Itl!llS A.1 through A.3, A.5. A.6, A.B, and A.9 above

2. eloud-top temperature lower than -6 .C but higher than -20 .C

3. VertiCil air velocity greater than -1.0 m/s in the region defined by
Item A.1. but no other vertical velocity or buoyancy restrictions

Table 2. HIPLU-l Primary response variables

1. CIC2
2. tiCS
3. eCRS
4. PICS
5. MVDS
6. AWCS
7. TFPI
8. TFE
9a. TIPA
b. TIPR
lOa. RERC
b. ~R

Cloud ice concentration, 2 .in after treatment
Cloud ice concentration. 5 .in after treatment
Concentration of crystals r1ll1ed, 5 .in after treatment
Precipitating ice number concentration, 8 .in after
treatment
Mean volume di~ter of precipitating ice particles,
8 .in after treatment
Average liquid water concentration. 8 .in after treatment
Tillie to first precipitating ice (particles with diilllE!ters
) 0.6 ~ in concentrations) 0.1 per liter)
Tine to first SWR-75 radar echo (15 dBZ)
Time to initial precipitation at +10 .C level. aircraft
llleasurement .
Time to initial precipitation at +10 .C level. SWR-7S
radar (15 dBZ)
Radar-estimated rainfall at +10 .C level. usin9 a constant
Z-R relationship
Aircraft-estimated rainfall at +10 .C level

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