occurred. Near-infrared Channel 2 reflectivity 
increases in value with increased plant leaf area 
and then drops dramatically after plant maturity. The 
difference between Channels 2 and 1 provides a 
measure or signature of plant vigor that scientists 
can use in assessing crop conditions. After the peak 
period in the plant growing cycle has been reached, 
total biomass decreases and the difference in the 
values of Channel 2 and 1 dramatically decline. 
AVHRR vegetation indices provide a quick 
discriminatory visual aid in assessing worldwide 
crop conditions. 
The interpretation of visible and near infrared 
radiation can be improved through the assignment of 
colors to Channels 1 and 2. The color coordinate 
system provides the assessor with mechanism to 
transfer AVHRR data to color graphics. The status of 
crops can be determined over time by using one of 
several crop indices as the primary coordinate. The 
color coordinate system enhances the interpretation 
of spectral responses of plants and allows the 
analyst to measure the areal extent of drought or 
crop stress. A profile of vegetation reflectance over 
time can be constructed for disaster-stricken areas. 
This profile can be compared with the profile of the 
same area for earlier years to provide an historical 
measure of impact, the point in the life cycle of the 
crop in which the disaster occurred, and the 
potential impact on yield (1). 
During 1983 NOAA and the Agency for International 
Development (AID) sponsored a workshop on Climatic 
Impact Assessments for Agriculture at the Asian 
Institute of Technology in Bangkok, Thailand. The 
workshop led to 1983 test assessment programs 
(Indonesia, Philippines, and Thailand) and an 
expanded program in South Asia (Pakistan, India, 
Nepal, and Malaysia). A Senior Experts Seminar on 
Drought Impact Assessment and Food Security was held 
in Bangkok, Thailand, January 1984. Policy-level 
managers for food security attended the seminar and 
prepared country plans that included training and 
technical assistance for test assessment using ground 
station and satellite data. 
Expanded capabilities of microcomputers have 
enhanced training in satellite applications in the 
developing world. In 1985, the agricultural 
assessments program will be expanded using 
microcomputers in Southeast Asia. Future assessment 
areas include: Equatorial West Africa, the Middle 
East, South Pacific, Mexico, and South America (N.E. 
Brazil, Paraguay and Uruguay). AISC has trained more 
than 76 foreign scientists and managers. Training 
has included scientists from Haiti, South America, 
EL Salvador, Belize, Costa Rica, Colombia, Venezuela, 
Ecuador, and Peru; Africa from Senegal, Sierra Leone, 
Ethiopia, Niger; and in Asia from Pakistan, India, 
Bangladesh, Sri Lanka, Nepal, Burma, Thailand, 
Malaysia, Indonesia, Philippines and Singapore. 
Training sets using recently developed satellite ima 
gery techniques have been developed for the African 
Sahel and Southeast Asia. These assessments will be 
displayed on personal computers in 1985 for training 
purposes. Plans for training programs in AISC in 1985 
focus on improving agroclimatic assessments through 
use of satellite imagery on microcomputers and 
expanded geographic coverage in West Africa, the 
Sahel, and South America. 
AFRICA: A CASE STUDY 
Monitoring the condition of agricultural resources 
in the tropics is a new application of meteorological 
satellite data. Drought, a natural disaster, expands 
over vast areas and lasts for months to even years. 
It is the principal weather related disaster facing 
most of the world's developing countries. Aside from 
crop failures and disastrous food shortages weather- 
related disasters impede economic development and 
create political instability. The ongoing 1984 
African drought has created large food relief 
problems and is generating further political tension 
in the Sahel. Assessments cannot eliminate these 
disasters but they can provide a warning to decision 
makers for planning food security programs. 
During 1984, major droughts struck three regions of 
Africa. In South Africa, hot dry weather damaged 
subsistence cereals in January, February and early 
March. The drought sharply reduced crop production 
in South Africa, Botswana, Lesotho, Zimbabwe, and 
parts of Mozambique and Zambia. The impacts were 
especially severe because these countries all 
experienced drought problems in the preceding year as 
well. In East Africa, crops planted in March and 
April were damaged by drought the first half of the 
year in Ethiopia, Sudan, Somalia, Kenya, Rwanda, and 
parts of Tanzania, Uganda and Zaire. The first six 
months of the year were the driest in over 40 years 
in central Kenya. In the third region, the Sahel 
zone of West and Central Africa, near record heat and 
dryness during July and August curtailed growth of 
crops planted in May, June, and July. Affected 
countries included Mauritania, Senegal, Mali, Burkina 
Faso, Niger, Nigeria and Chad. The drought in the 
Sahel resulted in crop and grazing losses over an 
area of approximately 500,000 sq. miles. For those 
countries impacted, that meant a reduction in crop 
production of almost 25 percent. The cost on local 
economies amounted to approximately $250,000,000. 
AISC scientists used the NOAA polar orbiting 
satellite for African vegetation assessments. Early 
in the growing season, satellite imagery indicated 
drought in the Sahel zone of Mali, Burkina, and 
Niger. Vegetation indices provided more detailed 
coverage of the drought affecting the Sahel zone of 
these countries. The mean vegetation indices for 
1984 suggest more stress in Niger, Northern Burkina, 
and Southern Mali, than in the earlier year. During 
July and August 1984, AISC staff prepared specific 
asessments for Ethiopia. July - August cumulative 
rainfall totaled 60 percent of normal in Tigray, 
Ethiopia, and 40 percent of normal in Wollo, 
Ethiopia, with rainfall sharply diminishing during 
the last 2 weeks of August. The color coordinate 
system indicates a significantly lower vegetation 
reflectance in 1984 than in 1983. 
AISC has verified results for most of Sahel Africa 
during the last several years. Droughts were 
successfully identified from 30-60 days before crop 
harvest. Specifically, forecast lead times were 30 
days before crop yield losses, 60 days before price 
changes, 90-180 days before declared food shortages. 
In August 1984, AISC designated food shortage alerts 
for Mauritania, Senegal, Mali, Burkina, Niger, and 
Chad. During this time, assessment products included 
early warning cables to AID and State Department 
Missions, and monthly maps of anomalous climate 
conditions to Food Relief Organizations. 
SATELLITE ASSESSMENTS AND TRAINING FOR THE MARINE 
SECTOR IN THE UNITED STATES 
The Assessment and Information Services Center 
regularly publishes marine assessments for coastal 
and marine resources. The Chesapeake Bay and the 
Gulf of Mexico are sites of AISC's marine assessments 
in the United States. In the Chesapeake Bay 
oceanographers are attempting to quantify the 
exchange processes between the Bay and the adjacent 
shelf by using satellite data. The physical 
processes (i.e., wind, currents, tide) which control 
the exchange of waters between the Chesapeake Bay and 
the adjacent continental shelf influence the passive 
transport of fish eggs and larvae. Recruitment of 
several fish species in the Bay, including menhaden, 
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