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| Titel |
Cereal Production Ratio and NDVI in Spain |
| VerfasserIn |
Antonio Saá-Requejo, Laura Recuero, Alicia Palacios, Carlos G. H. Díaz-Ambrona, Ana M. Tarquis |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250100956
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| Publikation (Nr.) |
 EGU/EGU2014-16979.pdf |
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| Zusammenfassung |
| Droughts are long-term phenomena affecting large regions causing significant damages both
in human lives and economic losses. The use of remote sensing has proved to be very
important in monitoring the growth of agricultural crops and trying to asses weather impact
on crop loss. Several indices has been developed based in remote sensing data being one of
them the normalized difference vegetation index (NDVI). In this study we have focus to know
the correlation between NDVI data and the looses of rain fed cereal in the Spanish area where
this crop is majority.
For this propose data from drought damage in cereal come from the pool of
agricultural insurance in Spain (AGROSEGURO) including 2007/2008 to 2011/2012 (five
agricultural campaigns). This data is given as a ratio between drought party claims against
the insured value of production aggregated at the agrarian region level. Medium
resolution (500x500 m2) MODIS images were used during the same campaigns to
estimate the eight-day composites NDVI at these locations. The NDVI values are
accumulated following the normal cycle of the cereal taking in account the sowing
date at different sites. At the same time, CORINE Land Cover (2006) was used to
classify the pixels belonging to rain fed cereal use including a set of conditions such
as pixels showing dry during summer, area in which there has been no change of
use.
Fallow presence is studied with particular attention as it imposes an inter annual variation
between crop and bare soil and causes decreases in greenness in a pixel and mix both
situations. This is more complex in the situation in which the avoid fallow and a continuous
monoculture is performed. The results shown that around 40% of the area is subject
to the regime of fallow while 60% have growing every year. In addition, another
variation is detected if the year is humid (decrease of fallow) or dry (increase of
fallow).
The level of correlation between the drought damage ratios and cumulative NDVI for the
cereal campaign obtained are classified according to their level of significance at 99, 95, 90
and 85%. Approximately half of the regions with high surface assurance have meaningful
relationships. In the regions where no significant relationships are achieved several situations
are discussed such as extreme situations in critical phenological periods that could have great
influence on the final yields.
Acknowledgements. This work was partially supported by ENESA under project P10
0220C-823. |
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