WMOD00399

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

USE OF METEOROLOGICAL SATELLITE DATA FOR THE DESIGN,
OPERATION AND EVALUATION OF WEATHER MODIFICATION EXPERIMENTS

by

(*)
T. H. Vander Haar

I . I NTRODUCT I ON

I. I In 1979 the worl dw i de ava i lab i I i ty of high reso I uti on geostati onary sate II i te data
is affecting weather forecasting and research in significant ways. Coupled with second
and third generation systems of near-polar orbiting satel I ites, the new World Weather
Watch network provides special opportunities for weather modification programs. The pur-
pose of this training paper is to describe the use of meteorological satel lite data for
the design, operation and "post-hoc" evaluation of weather modification experiments.

1.2 The paper refers to other, more len~lthy summaries with thei r sets of references.
It outl ines the sate) I ite observing systems of the early 1980's and refers to the basic
facts needed to use satel I ite data. In addition, statements and examples are used to
describe the various classes of hardware and computer software avai lable to display and
analyze the satell ite data. Examples Gf actual satell ite cloud cl imatologies are provided
as they were used in the design of weather modification experiments. Sample case studies
of satel I ite data illustrate operational applications. Finally, several post-hoe evalua-
tions are examined where satel I ite/air~raft and ground-based data are combined. Background
for the paper regarding PEP was drawn from PEP Reports I through 9.

2. OVERVIEW OF SATELLITE SUPPORT TO WEATHER MODIFICATION

2.1 Reynolds et E.l. [1978] provide a recent overview including speculation on the
future development sate II ite data appl ication possibi I ities. (It is included as ANNEX B
to this paper.) Reynolds and Morris [1978] and Morris [1979] describe very recent results
us i ng sate II i tes to determ i ne Cloud To,J Temperature (CTT> for seedab i I i ty cr iter i a. The
CrT work is based on the physical principles described by Grant and Elliott [1974].
At this time the largest body of results in the I iterature deals, as those noted above.
with the use of satel I ites in support of the modification of mid-latitude wintertime
orographic cloud systems.

2.2 However, an increasing amount of recent study has been given to the use of cloud
climatologies in the design of summertime cumulus weather modification projects (eg. H1PLEX,
see Reynolds and Vonder Haar [1976,1977,1978J; other areas, Stadt and Grant [1976]). Real
time operational support is addressed by Reynolds and Matthews [1976] . Scheetz and Grant
[1976] focused on very low level upslope clouds as viewed from satel lites.

2.3 Purdom [1974] and others have provided extensive discussion of satel I ite support
to mesoscale forecasting -- an important aspect of any weather modification project.
Griffith et E.l. [1976] , Smith and Kidder [1978], Reynolds and Smith [1978] and others
assess the use of satel I ites to determine precipitation amounts. More research is needed
but I imited "success" on certain types of cumulus ensembles has been reported. Combined
sate I I ite-radar-other data approaches!ook more promising with regard to precipitation
determination than either satel I ite or radar or gauge data alone. Hi I Iger and Vonder Haar
[1977,1979] report use of satellite tenperature and moisture soundings at the mesoscale
to define the environmental conditions before during and after a modification study or event.

*
Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado, USA