WMOD00399

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

iii

PREFACE

Opening Address on Behalf of the
Secretary General of WMO
delivered by Dr. R.D. Bojkov

On behalf of the Secretary General of the World Meteorological Organiza-
tion, it is a pleasure to welcome you to this Training Workshop on Weather Modifi-
cation for Meteorologists, called in accordance with a decision of the WMO
Executive Committee.

As most of you know, and many of you have actively been involved, WMO has
for many years been concerned and followed closely the developments in the field of
weather modification. It has supported studies and prepared reviews, some of which
have been published as technical notes; it has cosponsored a number of cloud
physics symposia. In view of the diversity of opinion about the effectiveness of
arti ficial weather modification, WMO has, in addition, issued statements on this
subject for general use and, in particular, to assist governments and those requir-
ing to make decisions in this field. It should be further noted that the WMO
seventh Congress (May 1975) asserted that WMO was the appropriate international
body with the necessary scientific and technical expertise in this field, and agreed
that the time had come for the Organization to become more active in this field in
order to be able to respond to requests for advice from Members, the United Nations
and other international organizations concerning weather modification and approved
as one of the most important research projects during the seventh financial period
(1976-1979) the WMO Weather ModificlJtion Programme. The most important part of
this Programme is a Precipitation Enhancement Project (PEP), about which we will
hear more during the sessions this week. The Programme will also provide for co-
ordination of research activities and the distribution of authoritative information
in respect of such fields as tropical cyclone modification, hail suppression and
fog dispersal, as well as increased studies of the physical and dynamical processes
underlying weather modification activities.

Congress went on to agree that scientifically convincing answers concern-
ing the feasibility of precipitation enhancement could best be advanced through an
internationally planned, executed and scientifically evaluated exercise as pro-
posed in the Precipitation Enhancement Project (PEP). In order that the conclu-
sions drawn from the PEP may command wide acceptance in the scientific community,
Congress stressed that the experiment must be meticulously prepared, executed and
evaluated. Moreover, the experiment would have to be conducted over a sufficient
number of years to detect any effect against a background of strong "noise"
represented by natural variations of rainfall amounts. The first stage of the
Precipitation Enhancement Project should be detailed studies of cloud populations,
including their dynamical and microphysical structure. This should not only permit