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Remote sensing for resources development and environmental management
Damen, M. C. J.

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Symposium on Remote Sensing for Resources Development and Environmental Management / Enschede / August 1986
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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
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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.
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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
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
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
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.