vork and 
Symposium on Remote Sensing for Resources Development and Environmental Management / Enschede / August 1986 
jld replace 
presently 
at scales 
nge. This 
stive. In 
tion and 
ted in the 
of the many 
e, and can 
rk 
Contribution of remote sensing to food security and early warning 
systems in drought affected countries in Africa 
Abdishakour A.Gulaid 
Department of Photogrammetry and Cartography, Technical University of Berlin, FR Germany 
ovides an 
e processes 
egional 
rtant for 
ontribute 
future 
-use and 
for Use 
cal Survey 
on DC : 
ABSTRACT: As a result of the disastrous drought that affected many countries in the Sahel Zone in 1973/74, the 
international community has been looking for means of obtaining immediate and reliable information on the potential causes 
of this terrible danger that threatens millions of human and animal lives. The Food and Agricultural Organization of the 
United Nations (FAO), for example, has established an early warning system for predicting food shortages in many developing 
countries. The United Nations Environmental Programme (UNEP) installed a global environmental monitoring programme 
(GEMS). Many developing countries have set up their own food security and early warning systems with the help of 
multilateral or bilateral technical cooperation projects. The common aim of these programmes is the collection, processing 
and analysis of relevant data with the help of one or several methods, and the subsequent presentation of the derived 
information to the planners and decision-makers in order to take appropriate measures in time. 
This paper assesses the role of remote sensing in the existing and the future food security programmes and early warning 
systems in developing countries with particular emphasis on the drought affected countries in Africa. 
chapsplan- 
eningen: 
ent Plan 
rinter. 
bo 1986. 
bi area. 
hort study 
s of the 
roject, 
Agriculture. 
ure. 
ess. 
y and region. 
sis. London 
Institute 
landscape 
leningen : 
i^jthe Session 
) Governing 
i vironmental 
1 INTRODUCTION 
The immediate consequences of the disastrous drought in 
1973/74 were water shortage, a drastic decline in crop and 
livestock production, the loss of hundreds of thousands of 
human and animal lives, and the destruction of the 
ecological balance that caused the encroachment of the 
desert with an unprecedented acceleration. In order to 
overcome these problems, various programmes were 
launched at the international, regional and national levels. 
Some of these programmes, such as the evacuation and the 
immediate supply of relief aid to the affected population, 
were short-term; others were mid-term or long-term such 
as the food security programmes and the rehabilitation 
measures, namely, the reforestation and the soil 
conservation programmes. 
The main objective of food security programmes is to 
ensure the population of a country with a certain minimum 
amount of food per capita. One instrument for the food 
security is the early warning system, whose task is the 
acquisition of reliable information on the situation of the 
available food supply and demand in the country, so as to 
increase its preparedness to better meet the eventual food 
shortages. The information needs to be collected on various 
interactive factors such as price policy, weather, soil, and 
the type of technology available, which affect production 
of food both from crops and livestock. The type of 
information and the methods of collecting it vary widely. 
The discussion in this paper will be confined to the type of 
information that could be derived by means of remote 
sensing methods and relevant to this topic. 
Remote sensing from aircraft has been used since the 
1930's, however its broad applications increased with the 
industrial development of aircraft technology and 
photographical materials after the Second World War. The 
introduction of colour and infrared-colour film, has made 
the monitoring of crop conditions and identification of 
insect pests and crop diseases possible. Aerial photography, 
as is known, is today an important base for any major 
natural resource survey project, specially in developing 
countries where the available relevant maps are usually not 
updated. 
The improvement in the remote sensing technology in 
respect of hardware and software in the last decade and 
the availability of multisensoral (MSS, TM, SPOT, 
METEOSAT, NOAA, etc.) and multitemporal data offers 
the user today a wider choice to acquire the information 
needed. 
Through the launching of the first Earth Observational 
Satellites, LANDSAT 1-3 in the 1970's, the remote sensing 
user community turned to this new source of image data in 
order to derive information according to their needs. 
Experiments using LANDSAT Multispectral Scanner (MSS) 
images for land use and resource management among 
others started. 
In 1974 The National Space Agency (NASA), the US 
Department of Agriculture, (USDA), and the National 
Oceanic and Atmospheric Administration (NOAA) initiated 
the Large Crop Iventory Experiment (LACIE), a LANDSAT- 
image based programme correlated with meteorological 
information, to survey wheat production among the world's 
largest producers (Macdonald,Hall 1978). Though the 
technology applied was relatively sophisticated at that 
time and could hardly be transfered to developing 
countries, the experience collected in this pilot project was 
valuable and encouraging. Despite certain limitations such 
as the spatial resolution of the LANDSAT images, which 
caused user reservations at the beginning, the research and 
application of this type of data in renewable resources such 
as hydrology, agriculture and forestry has increased 
worldwide. This became useful for many developing 
countries in providing a range of thematic maps in the 
scale of 1:250.000 and smaller. 
The LANDSAT series continued with the launching of 
LANDSAT 4 in 1982 and LANDSAT 5 in 1985. The 
Thematic Mapper data of these two satellites have shown a 
major improvement in the spatial resolution, particularly in 
agricultural and vegetation covered areas. The 
disadvantage of the LANDSAT TM is the bulk of data that 
should be processed and the eventual costs. 
Today the user community is eager to see the 
preliminary results of the first images of SPOT that was 
launched in February 1986. Besides the expected 10-20 m 
ground resolution, the introduction of stereoscopic 
coverage is surely a major achievement for various fields 
of application such as the topographic and geological 
mapping. 
Besides the earth resource observation satellites, there 
is the other group of satellites, the environmental 
satellites, whose main task is to monitor the global 
weather conditions. These meteorological satellites are 
either geostationary (GEOS, METEOSAT) with an altitude 
of 36000 km above the earth or polar-orbiting (NOAA-7, 
NOAA-9) with a flight altitude of around 860 km. The 
METEOSAT data can be received every 30 minutes, 
whereas the NOAA-9 data could be obtained twice a day. 
This frequent acquisition of data allows the weather 
forecasters to predict imminent hazards early enough.