Agriculture Reference
In-Depth Information
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[262
Line
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-0.0
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Norm
PgEn
Fig ure 19.4 Rainfall and NDVI combined-departures versus rainfall anomalies (with respect
to normal) for Burkina Faso (top) and Mali (bottom) for the year 2001.
[262
have deficts in rainfall distribution. Here again, the RNCD method shows
higher positive departure than rainfall records, which show the same area
as above to slightly above average. It should be noted, however, that slight
differences between the two methods may be due to the difference in the
normalization of the departures from average. RNCD differences between
current values and averages were normalized by the standard deviation,
whereas rainfall departures were normalized by the average. In any case,
the RNCD method captured the slightest anomalies in rainfall pattern.
The RNCD index is directly related to agricultural production. When
these anomalies are large, its relationship with crop production is expected
to be strong. However, when they are mild, as in the present case, the
relationship of the index with crop production may be weak. In these
co nditions a crop-specific method such as the WRSI should be used for
better results.
C onclusions
The FEWS and FEWS NET activities have used remote-sensing satellite
data to monitor drought and famine since the late 1980s. NDVI was first
 
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