 |
| Titel |
Spatial and Temporal Dynamics of the Leaf Area Index of the Caatinga Biome |
| VerfasserIn |
Everton Alves Rodrigues Pinheiro, Quirijn de Jong van Lier, Klaas Metselaar |
| Konferenz |
EGU General Assembly 2015
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250102134
|
| Publikation (Nr.) |
 EGU/EGU2015-1413.pdf |
|
|
|
|
|
| Zusammenfassung |
| Leaf Area Index (LAI) is an important characteristic of ecosystems with a prominent role in
processes such as transpiration, photosynthesis and interception. The Caatinga biome is a
unique semiarid ecosystem ocurring in a specific region of Brazil. An important main feature
of this biome is the leaf shedding and regenerative capacity of its species. The aim of this
study was to quantify both spatial and temporal dynamics of the LAI of the Caatinga
biome in the Aiuaba Experimental Basin, an integrally-preserved Caatinga reserve,
coordinates 6º42’S; 40º17’W. The research site (12 km2) was divided into three main Soil
and Vegatation Associations (SVA). For each SVA the soil type and root depth are
respectively, Acrisol –0.8 m, Luvisol – 0.6 m and Regosol – 0.4 m. The LAI was
estimated by SEBAL algorithm applied to eleven satellite images from Landsat 5.
The values of LAI estimated by SEBAL were correlated to the mean soil water
content of the 15 days previous to the satellite image date. Eight images were used to
generate a simple regression model, yielding a range of coefficient of determination
from 0.89 to 0.92. Three other images were used to validate the equations. The
Nash-Sutcliffe efficiency coefficient ranged from 0.76 to 0.94. Using the validated
correlations, the LAI was calculated over the time for each of the three SVA, from
2004 to 2012. For SVA1, SVA2 and SVA3, the avarage values of LAI during the
rainy season were 0.97, 1.12 and 1.07, respectively. During the dry season, the
mean values were 0.15 for SVA1 and 0.11 for SVA2 and SVA3. The vegetation
showed abrupt LAI changes, and the average previous 15 days soil water content
was a good indicator for this. The study has shown that the maximum LAI was
relatively stable over the years, occurring between March and April. The spatial
behavior of LAI appeared to be similar, independently of the soil type and root depth. |
|
|
|
|
|
|