WMOD00399

• Title: WMO Training Workshop on Weather Modification for Meteorologists - Lecture Notes
• Date: 12/1/1979
• Weather Modification - Doc Type: Report

the

I
I
OBJECTIVES OF PEP :
I

The WHO Executive Committee, at its twenty-eighth session in 1976, defined
scientific objectives of the Precipitation Enhancement Project ak follows:

To provide Members with reliable information about the probabllities of
successful artificial intervention in meteorological processe~ with the
object of increasing the amount of precipitation over an area of the or-
der of 10 000 km2. The size of the area for the proposed p~oject (i.e.
the target and nearby control areas) should be somewhere aroLnd 50 000
km2, a scale large enough to provide adequate evaluation of scientific
feasibility and economic benefit, but small enough to permit the use of
adequate methods for seeding and observations;

'!'

(a)

(b)

To demonstrate, at a satisfactory statistical significance lrvel over a
relatively short experimental period (five years), that any fncrease ob-
served is not a chance event but is associated with the see~ing. The
principal evaluation of this experiment will be in terms of II precipi-
tation at the ground; I

To obtain sufficient understanding of the meteorology and cloud physics
I
in the area of the experiment to ensure that the statistical association
of seeding, and any increase in precipitation, will be generblly accept-
I
able as a cause-and-effect relationship; ,
I
I
To make an examination outside the target area in order to ~etermine
whether any benefits of seeding extend over areas greater t~an the
target area, or whether there has merely been a comparatively local
redistribution of precipitation; i
I

(c)

(d)

(e)

(f)

to cloud micro-
I
strengthen the
I
I

To obtain well-documented scientific evidence that may leadlto the opti-
mization of the effects of seeding. For this purpose, a s~ries of sys-
tematic cloud physics measurements should be taken on a r6utine basis.
This would allow the application of statistical stratification I techniques
could shed more light in the quanti-

To be able to make some recommendations about the applicability of the
PEP procedures to other areas of the world; I

To assess the environmental impact of precipitation-enhancement activities,
both within and outside the experiment target area.

To make systematic measurements, varying from mesoscale
structure, in order to develop additional co-variates to
power of the statistical analysis;

to relevant physical parameters, and
tative aspects of seeding techniques;

(g)

(h)

!